Clubjazz - Honda Jazz & HR-V Forums

Honda Jazz Forums => Honda Jazz Mk4 2020 - => Topic started by: John Ratsey on September 03, 2020, 04:03:54 PM

Title: MPG for those interested
Post by: John Ratsey on September 03, 2020, 04:03:54 PM
First refuelling 465 miles, 30.65 litres so 69.3 mpg (car claimed 73 mpg).

Second refuelling 515 miles, 32.90 litres so 71.2 mpg (car claimed 75.1 mpg).

The "fibometer" appears to be about 5% optimistic - nothing new there!
Title: Re: MPG for those interested
Post by: Jocko on September 03, 2020, 07:15:30 PM
You can have my crown. Great mpg.
Title: Re: MPG for those interested
Post by: John Ratsey on September 03, 2020, 09:01:27 PM
You can have my crown. Great mpg.
Your 60-ish mpg from a Mk. 1 Jazz is a greater achievement. I suspect that I won't keep the crown for very long as someone will find that their normal driving hits the sweet spot in the system efficiency. The sweet spot on the Mk 3 Jazz is at about 40 mph https://www.theaa.com/about-us/newsroom/fuel-economy-record-attempt . The Mk 4's optimum speed is probably slightly higher - just above the threshold at which direct drive is enabled, which my initial data logging suggested is at around 42 mph.

Title: Re: MPG for those interested
Post by: John Ratsey on September 11, 2020, 09:23:46 PM
Another 546 miles of mainly A road cruising and 33.76 litres was needed to top up the tank which I calculate to be 73.5 mpg. The car reckoned I could have continued for another 77 miles although the mpg suggests this should be 100 miles - most likely Honda's algorithm at work to encourage the driver to refill. Here's the car's version of the mpg to date. My average to date for the computer's optimism bias is 4.6%. I'm expecting the mpg to drop as the weather gets colder.
Title: Re: MPG for those interested
Post by: Downsizer on September 12, 2020, 05:02:17 PM
Iíve been averaging 52 mpg in my Mk3 over 4 years of ďdefensiveĒ driving (40,000 miles) so based on your figures I should be able to average 72 mpg in a Mk4.  This would save me about £300 a year, but against that I would lose my current £30 p.a. road tax.  I think Iíll keep the Mk3 for 2 or 3 more years, but Iíll soon need to replace the original front tyres!
Title: Re: MPG for those interested
Post by: chicksee on September 12, 2020, 07:16:45 PM
Back from a trip, clocked 430 miles, car said 60.4 mpg, actual worked out at 60.1. Not as good as some but quite happy with that.
Title: Re: MPG for those interested
Post by: John Ratsey on September 12, 2020, 08:33:46 PM
Iíve been averaging 52 mpg in my Mk3 over 4 years of ďdefensiveĒ driving (40,000 miles) so based on your figures I should be able to average 72 mpg in a Mk4.  This would save me about £300 a year, but against that I would lose my current £30 p.a. road tax.
I agree that the current tax regime doesn't provide much incentive to move to a more efficient vehicle. The government should recalculate the tax on older vehicles using data from the current WLTP test given that this was introduced to reduce the ease for vehicle manufacturers to game the system.

A less-well publicised benefit of the new Jazz is that it can provide substantial power without any hesitation which makes the vehicle feel much more nimble so you feel you've got a more powerful vehicle without the associated fuel cost penalty.

Back from a trip, clocked 430 miles, car said 60.4 mpg, actual worked out at 60.1. Not as good as some but quite happy with that.
Did your trip include a significant proportion of motorway cruising at the legal limit? That would drop the mpg by a substantial amount due to the aerodynamic drag losses while the hybrid system provides little benefit.

PS: Do you need to change the vehicle in your forum profile? It says "2012 ES".
Title: Re: MPG for those interested
Post by: chicksee on September 12, 2020, 11:21:21 PM
Yes, mostly motorway driving with average speed between 60-70
Changed vehicle profile, thanks.
Title: Re: MPG for those interested
Post by: andruec on November 11, 2020, 03:16:10 PM
Interesting figures. thanks. Those are slightly better than my 1.8 Toyota Corolla Excel. What size tyres does that Jazz have? Supposedly the tyres on my Excel cost about 10% in fuel consumption.

Also - what's the Jazz like for road height? One criticism of the Corolla is that it sits fairly low to the ground which can make getting in and out a bit awkward for those who are no longer 'in the first flush of youth' :)

If the hybrid Jazz has as much interior space and is as easy to get in and out of as previous versions then maybe Honda have managed to beat Toyota at their own game. I had my doubts when I saw the predicted figures two years ago which is part of why I switched to Toyota.

The other reason was the poor build quality and customer service I experienced with my Mk3.
Title: Re: MPG for those interested
Post by: John Ratsey on November 11, 2020, 04:05:34 PM
Tyres are 15 or 16" depending on vehicle version - see https://www.honda.co.uk/cars/new/jazz-hybrid/specification.html. The ride height for the basic Jazz is where you'd expect it for a Jazz while the Crosstar (185 / 55 R16 tyres) is about 1" higher and the fuel economy suffers a bit (the roof rails can't help). You can get a lot of insight into fuel economy issues by looking at the WLTP fuel consumption data for the different test cycles - eg the fuel consumption increases substantially over 60 mph (the relatively high and boxy shape of the Jazz doesn't help the aerodynamics but I recall looking at the Corolla WLTP numbers and seeing that they showed a similar trend).

I understand that the Crosstar is selling better than Honda anticipated - perhaps a lot of their customers value the extra height which is what I primarily bought it for. Internal space for the passengers is very generous but the boot is a bit small due, I think, to Honda setting the rear seats such that they could be folded forward without removing the headrests (and the magic seats hare still there). There's no home for a spare wheel as the battery is under the front part of the boot floor but there is a cubby hole for bits and pieces under the rear part of the boot floor.

The build quality feels much better than the Mk 3 Jazz and the eHEV system has transformed the performance while the engine is almost inaudible unless it is asked to work hard (eg steep hill or heavy acceleration). It's worth giving the new Jazz a test drive although customer experience is a lottery depending on the dealer. However, the connectivity feature is work in progress and Honda are being slow to respond to user problems. Fortunately, this is a bit of garnish and not critical.
Title: Re: MPG for those interested
Post by: andruec on November 11, 2020, 06:21:52 PM
Sounds hopeful then but I don't like your comments on the connectivity. Sounds like Honda are no better than they were when I last dealt with them :(

I normally travel at 60 mph on motorways but coming back from my Dad's funeral in Wales (190 miles) a couple of weeks ago I pegged it at 80/90 and it certainly does impact on mpg. Going up I managed 65 mpg but coming down it was 52 mpg. Still a pretty good figure considering I suppose.

But my next car will be full EV. Oh and if I can arrange it will have a colour LCD screen like my Corolla does (the main part at least). I prefer a digital speedometer and there's something very cool in being greeted by animated graphics on your dashboard when you switch on :)
Title: Re: MPG for those interested
Post by: Vinylseats on November 30, 2020, 01:34:54 PM
Another 546 miles of mainly A road cruising and 33.76 litres was needed to top up the tank which I calculate to be 73.5 mpg. The car reckoned I could have continued for another 77 miles although the mpg suggests this should be 100 miles - most likely Honda's algorithm at work to encourage the driver to refill. Here's the car's version of the mpg to date. My average to date for the computer's optimism bias is 4.6%. I'm expecting the mpg to drop as the weather gets colder.

That's a great amount of miles that can be achieved on a tank of fuel - almost diesel figures. And it'll probably do more as the engine wears in over time.

It's these sorts of figures which have given me an interest in the new Jazz as I want a car that needs filling up as little as possible on long journeys. But I know hybrids, especially the older ones, don't do quite as well on fuel at motorway speeds as standard petrols so I hadn't been interested in them until this new lot of engines have come along which I understand are better on motorways than they once were.

I'm still unsure if it's worth me paying the higher price for a hybrid when I also travel on the motorway a fair bit, but it seems they're improving all the time.
Title: Re: MPG for those interested
Post by: John Ratsey on December 03, 2020, 10:14:30 AM
It's these sorts of figures which have given me an interest in the new Jazz as I want a car that needs filling up as little as possible on long journeys. But I know hybrids, especially the older ones, don't do quite as well on fuel at motorway speeds as standard petrols so I hadn't been interested in them until this new lot of engines have come along which I understand are better on motorways than they once were.

I'm still unsure if it's worth me paying the higher price for a hybrid when I also travel on the motorway a fair bit, but it seems they're improving all the time.
The hybrid system is effectively redundant when cruising at motorway speed although it's possible that Honda's single direct drive gear is mechanically slightly more efficient than a conventional (or CVT) gearbox. However, if you encounter stop-start traffic on a motorway then the hybrid system comes into play and it's possible, as I discovered on mine of my first trips, to spend 5 minutes or more of crawling without the engine coming on. And, when the engine does wake up because the battery is getting low, it revs to an efficient 2000 rpm to both move the car but primarily put more charge into the battery so it can go to sleep again.

A relatively short and high vehicle such as the Jazz will never be the most efficient motorway cruiser as the drag coefficient will be higher than on a longer, lower vehicle, but interior space and a higher seating position are often factors which attract Jazz purchasers. If you want to figure out which vehicles are the best motorway cruisers then dig into the test data and look at the WLTP "extra-high" results which involve a lot of driving at up to 80 mph https://en.wikipedia.org/wiki/Worldwide_Harmonised_Light_Vehicles_Test_Procedure. I'm happier at 60 mph in which case the WLTP "high" results are more applicable. The WLTP data also highlight how much the road transport carbon footprint can be reduced if people drove more slowly, but that's another matter.

Another benefit of a hybrid system over a plain petrol engine is the low-end torque provided by the electric motor which translates to a much more pleasant driving experience.
Title: Re: MPG for those interested
Post by: JazzMusic on December 03, 2020, 10:52:37 AM
As it got colder we see around 52 mpg, 15-20 mpg less than in summer.

A big hit was a hurry highway drive with 70 mph, resulting in 40 mpg once. :o

So, mpg correlates strongly with speed and climate, a little bit more than expected.
Title: Re: MPG for those interested
Post by: sparky Paul on December 03, 2020, 11:00:05 AM
As it got colder we see around 52 mpg, 15-20 mpg less than in summer.

Great summer mpg, but that's a large seasonal variation.
Title: Re: MPG for those interested
Post by: madasafish on December 03, 2020, 11:20:21 AM
I would expect a hybrid - where the engine switches on and off regularly - to gave a cooler running engine. In winter with colder air through the radiator - the engine may run a lot cooler and hence be significantly less efficient when running than an ICE car.
Title: Re: MPG for those interested
Post by: John Ratsey on December 03, 2020, 11:43:48 AM
I would expect a hybrid - where the engine switches on and off regularly - to gave a cooler running engine. In winter with colder air through the radiator - the engine may run a lot cooler and hence be significantly less efficient when running than an ICE car.
I was surprised that Honda didn't provide thermostatically-controlled blinds for the radiator to restrict cold air entry to the engine compartment to address this problem which is entirely foreseeable. I think they did this on the new CR-V. The cold engine problem is exacerbated by the cabin heating sucking whatever heat there is out of the engine coolant due to Honda not designing the electrically-operated aircon to run in reverse as a heat pump plus, on the Crosstar, the absence of the undertray will also help keep the engine compartment cold.

While the WLTP testing is an improvement on what came before, it should have included a cold weather stop-start traffic test to help focus vehicle designers' minds on this aspect. Longer journeys with the engine running continuously under moderate load won't have the cold engine problem but I reckoned it took at least 5 miles to get my HR-V running efficiently on a cold day.
Title: Re: MPG for those interested
Post by: JazzMusic on December 03, 2020, 12:24:40 PM
I would expect a hybrid - where the engine switches on and off regularly - to gave a cooler running engine. In winter with colder air through the radiator - the engine may run a lot cooler and hence be significantly less efficient when running than an ICE car.
I think they took care of this. In the old Honda Insight the base coolant temp was about 10 deg C lower than on other Hondas. But even then some owners have fitted cardboards in front of the radiator to extract more heat for more efficiency and more heating in the cabin. But the effect was in the single digit range, not 10 or 20%.

I was surprised that Honda didn't provide thermostatically-controlled blinds for the radiator to restrict cold air entry to the engine compartment to address this problem which is entirely foreseeable.
+1. Not sure if it was cost cutting, max reliability or no big impact.

Two things would be interesting to know: engine revs and coolant temp, both seem to be not available for the driver.

One more observation: the engine revs higher than in summer. More noise, not disturbing, but noticable.

EDIT: found a solution for WT and RPM: if you pull the steering wheel back there's is enough space for a scangauge.
Title: Re: MPG for those interested
Post by: JazzMusic on December 08, 2020, 11:58:25 AM
I've some more observations with my ScanGauge.
As John Ratsey pointed out somewhere in this forum a cold engine starts with 1600 rpm until the coolant temp is 40 deg C and charges the hybrid battery, I guess to warm it up too.
After that EV is available unless you start the heating. In all my cars I've let the engine warm up before using cabin heating. When I switched the heating ON to 22 deg C the coolant temp lost 10-20 deg C, BUT not so in the new Jazz.
When I active the heating in the Jazz the engine management seems to let the engine more often to supply heat for the cabin. The coolant temp range is between 60 and 80 deg C.
Title: Re: MPG for those interested
Post by: John Ratsey on December 08, 2020, 07:56:38 PM
In all my cars I've let the engine warm up before using cabin heating. When I switched the heating ON to 22 deg C the coolant temp lost 10-20 deg C, BUT not so in the new Jazz. When I active the heating in the Jazz the engine management seems to let the engine more often to supply heat for the cabin. The coolant temp range is between 60 and 80 deg C.
I also keep the cabin heating off until the engine has had opportunity to warm up. Using the heated seats will help to keep the front seat occupants warm and also uses some of the electricity. However, this doesn't help with demisting the windscreen.
Title: Re: MPG for those interested
Post by: JazzMusic on December 09, 2020, 10:12:52 AM
I also keep the cabin heating off until the engine has had opportunity to warm up. Using the heated seats will help to keep the front seat occupants warm and also uses some of the electricity. However, this doesn't help with demisting the windscreen.
The engine heats up pretty quickly without doing much driving.
I'm using heated seats, heated steering wheel (almost always in winter), set aircon to recirculate and switch the fan OFF. A/C also OFF. No problem with misting so far when I've let the A/C to loose the moisture by switching it OFF miles before I let it sit overnight. When the engine is warm enough (60 deg C) I switch the fan ON and set the temp to 22-24 deg C and use fresh air but still with A/C OFF.
A/C ON is a culprit in winter. Sure it helps to demist the windows but it stores so much moisture that you can't switch it OFF the next time you start a cold engine/interior. You're forced to leave the A/C ON to demist the windows.
I know I'm using A/C not much (or just on a monthly base) but never had any problems with it in several cars but I also do an A/C service every 2-3 years which contains demoisturing, new oil, filled freon up to the top.
Title: Re: MPG for those interested
Post by: Expatman on December 11, 2020, 04:17:32 PM
Why would you switch A/C off? Surely leaving it on with recirc will dry out the air and so reduce condensation more be quickly. That's the advice in my Skoda Yeti's manual - also has heated windscreen which quickly eliminates any condensation anyway.
Pity Jazz doesn't offer heated windscreen even as an option, I believe heated windscreen is a real safety item and more important than some of the more esoteric items that are included as safety items.
Title: Re: MPG for those interested
Post by: JazzMusic on December 11, 2020, 04:56:58 PM
Why would you switch A/C off?
Worse fuel economy and even drier air than outside.
Title: Re: MPG for those interested
Post by: IanG on March 09, 2021, 05:37:10 AM
In the countries where a non hybrid Jazz is available, the digital instrument cluster includes a bar display rev counter at the top of the display and the battery charge gauge is replaced by a water coolant gauge.
I guess on the hybrid model, with the ICE only operating part time, a rev counter is deemed less useful, particularly during the times when the ICE is acting as a generator and the revs may be more constant. Possibly, as the engine temperature is less likely to remain at a consistent regular running level due to part time ICE operation, the coolant temp gauge is replaced with a two stage warning light indicator, to alert if coolant temp is too high.

On the non hybrid models, the blanked out switch near the gear selector is fitted with a start/stop system deactivation switch.

In some markets there is also a heated screen switch in the panel which includes the parking sensor switch. I think this may just heat the windscreen in the wiper park position area, as is the case on some Kia vehicles.

I wondered why the dash lighting illumination switch was over large, then saw that, in some countries, the lower half of the circular switch features a ĎTRIPí button. Assuming this resets the trip counter or accesses the trip counter mode, rather than accessing the trip counter using the menu system. Perhaps these models have a less compressive range of trip counter features, so a simple reset button is all thatís required, same as the trip reset buttons that feature on many analogue instrument clusters.

Would be nice to have the rear seat centre armrest that some countries receive, particularly as the rear accommodation is generous for a small car. Some of the UK specs show this as a standard feature but I havenít seen any UK models with it.
Strangely, the cars that have rear centre armrest often seem to have a tray between the front seats, rather than a front centre armrest/cubby box, which Iíd have thought was more useful.
Title: Re: MPG for those interested
Post by: Arthur70 on March 12, 2021, 06:14:08 PM
To John Ratesy.

Great figures there John.  Do you make a conscious effort to drive economically or is that mainly motorway mileage.

Just curious.
Title: Re: MPG for those interested
Post by: John Ratsey on March 13, 2021, 08:45:36 AM
Great figures there John.  Do you make a conscious effort to drive economically or is that mainly motorway mileage.

Just curious.
A valid question. I'm happiest pottering along on a rural A road at 50mph and do my best to avoid motorways. However, when on a motorway I tend to use the lorry lane at 60mph with the occasional burst of extra speed to get past a lorry.

The Crosstar isn't a very aerodynamic shape which means that the drag losses mount up at higher speeds. I don't like driving in towns either but have noticed that the hybrid system is happy under those conditions as it also is during stop-start traffic on a motorway.
Title: Re: MPG for those interested
Post by: Jazzik on March 22, 2021, 05:27:44 PM
Just out of curiosity, I have compared the actual measured average fuel consumption of 3 competing small hybrids on "Spritmonitor" (www.spritmonitor.de/en/) : De Honda Jazz e:HEV, the Toyota Yaris Hybrid and the Renault Clio E-tech.
Of course this is not really representative yet: few cars, little miles.
The (preliminary) conclusion, however, is a bit surprising. The Jazz (62 mpg) and the Yaris (63 mpg) virtually no difference, the Clio however, at 52 mpg, is quite disappointing.

It looks like "Japan rules"  :D
Title: Re: MPG for those interested
Post by: guest10167 on April 04, 2021, 08:40:01 AM
Just out of curiosity, I have compared the actual measured average fuel consumption of 3 competing small hybrids on "Spritmonitor" (www.spritmonitor.de/en/) : De Honda Jazz e:HEV, the Toyota Yaris Hybrid and the Renault Clio E-tech.
Of course this is not really representative yet: few cars, little miles.
The (preliminary) conclusion, however, is a bit surprising. The Jazz (62 mpg) and the Yaris (63 mpg) virtually no difference, the Clio however, at 52 mpg, is quite disappointing.

It looks like "Japan rules"  :D

Indeed!
What I find even more interesting, is that the Jazz is bigger, a lot heavier and more powerful than the Yaris, but fuel efficiency is similar. So for me, Honda rules  ;)
Title: Re: MPG for those interested
Post by: guest10167 on April 04, 2021, 09:07:21 AM
Just had my first refuelling.

799.7 km (about 497 miles) - 32.59 litres (about 7.2 gallons) - 4.08 l/100 km (about 69.24 mpg)

The car indicated 3.9 l/100 km, so it's about 5% off

Mostly commuting with speed limits of 50-70 kph in "D" with ECON mode on and use of ACC where possible. I go to work before 6 am, which means a lot of cold starts. The car sits in the garage overnight. I only use aircon when I need it, for demisting or when the car is too hot (not often so far). Heating is on, but usually not higher than 20 degrees. There were only a few short stretches of motorway, where I try to stay between 110-115 kph.

I'm quite pleased with this fuel economy. The car is less than a month old, and apart from last week, the weather hasn't been warm yet. So I expect to get even better mileage in the future!
Title: Re: MPG for those interested
Post by: Jocko on April 04, 2021, 10:45:46 AM
69.24 mpg
That is excellent. That is the BEST I have ever achieved with my Mk 1. Come the summer, you should easily exceed that.
Title: Re: MPG for those interested
Post by: guest10167 on April 04, 2021, 12:05:00 PM

[/quote]That is excellent. That is the BEST I have ever achieved with my Mk 1. Come the summer, you should easily exceed that.
[/quote]

Thatís really impressive. I had a 2006 Fiat Panda 1.2 for four years (bought in 2015). The best I achieved with that car in summer was about 55.4 mpg... Haha. Fun car to drive though.
Title: Re: MPG for those interested
Post by: Downsizer on April 04, 2021, 01:40:57 PM
I was initially sceptical about the claimed efficiency benefits of hybrid technology, as all the energy still comes from petrol.  However, the real world figures reported here show that the combination of engine efficiency and regenerative braking make improvements of around 35% very realistic.
Title: Re: MPG for those interested
Post by: E27006 on April 11, 2021, 12:27:29 PM
I was initially sceptical about the claimed efficiency benefits of hybrid technology, as all the energy still comes from petrol.  However, the real world figures reported here show that the combination of engine efficiency and regenerative braking make improvements of around 35% very realistic.

The hybrid scores in several ways, one being that kinetic energy is converted to electricity and  recuperated (stored) in the battery while braking or decelerating, and the stored electricity can be converted back to kinetic energy to propel the car. A non-hybrid  simply wastes kinetic energy to heat in the brake pads and discs . Other differences are adoption of the Atkinson cycle for the engine, which trades off torque for economy of  fuel consumption, Atkinson cycle engines are better when assisted by a hybrid electric motor to plug the gap for reduced engine torque
Title: Re: MPG for those interested
Post by: John Ratsey on April 13, 2021, 10:13:14 PM
The hybrid scores in several ways, one being that kinetic energy is converted to electricity and  recuperated (stored) in the battery while braking or decelerating, and the stored electricity can be converted back to kinetic energy to propel the car. A non-hybrid  simply wastes kinetic energy to heat in the brake pads and discs . Other differences are adoption of the Atkinson cycle for the engine, which trades off torque for economy of  fuel consumption, Atkinson cycle engines are better when assisted by a hybrid electric motor to plug the gap for reduced engine torque
Also the hybrid system means that the engine (when running) spends more time in its most efficient range. Something I noticed when I first got my Crosstar and used Torque + a Bluetooth OBDII reader to monitor the engine behaviour was that the engine was never run at below 1600 rpm. My presumption is that excess power goes to the battery which then takes over and lets the engine go to sleep. This behaviour is very noticeable in crawling traffic. The hybrid system, however, provides minimal benefit during motorway cruising.
Title: Re: MPG for those interested
Post by: guest10167 on June 01, 2021, 02:59:38 PM
Today, for the first time since purchasing the car in March, my Jazz started in EV mode with 5 bars of Ďjuiceí in the box, after standing still outside for 7 hours! Weíre having a hot spell here in Belgium (25įC and up), and itís clearly having a positive effect on the battery.
While driving home from work, EV mode also came on more often than I was used to until now. Average consumption was 3.8 l/100km at departure, and after a 20 min. drive had dropped to 3.6 (about 78 mpg) with A/C on. I have ECON on in B mode.
This is making me very optimistic about summertime fuel consumption  :D
Title: Re: MPG for those interested
Post by: nowster on June 21, 2021, 11:52:32 PM
I've just done my second petrol fill. Same pump as first one. Same number of "clicks" from the pump.

I found that the car's own "trip counter" mpg figure is very close to the measured one: only about 2mpg more optimistic.

448 miles of mixed driving and 32 litres of fuel: 63.6mpg.

For the same sort of (ab)use in the Mk2 I'd be looking at about 45mpg at best.
Title: Re: MPG for those interested
Post by: springswood on June 22, 2021, 08:40:04 AM
Once again I'm getting Jazz envy.

My impression is that another advantage of hybrids is that the efficiency of petrol engines is much better at constant speed. I notice with my OBD reader that any acceleration, however gentle, causes the consumption to drop dramatically. Presumably the Jazz Mk2 hybrid doesn't have an Atkinson cycle engine but would have this benefit. If I'm right, that is, I might be talking out of my hat  ;D.
Title: Re: MPG for those interested
Post by: chicksee on June 22, 2021, 10:25:23 AM
I've just done my second petrol fill. Same pump as first one. Same number of "clicks" from the pump.

I found that the car's own "trip counter" mpg figure is very close to the measured one: only about 2mpg more optimistic.

448 miles of mixed driving and 32 litres of fuel: 63.6mpg.

For the same sort of (ab)use in the Mk2 I'd be looking at about 45mpg at best.

Pretty much the same, been away for a week approx 400miles done and 63.3 mpg, quite happy with that.
Title: Re: MPG for those interested
Post by: Zaier on June 22, 2021, 11:27:39 AM
Summer Time!
Even with extensive use of A/C and a bit of motorway, I was able to achieve 3.9L/100km, which translates to 72,4 mpg UK
Second tank which such a great result, the engine and the battery likes Italian heat.
Title: Re: MPG for those interested
Post by: Hicardo on June 27, 2021, 04:08:58 PM
hi folks, im averaging just a smidge over 60mpg in mixed driving over the first 2 weeks of ownership.  mostly motorway though.  think thats more than ok for a brand new engine.  single trip high score so far is 76mpg over about 20 miles, country roads, aircon on, eco mode  ;D
Title: Re: MPG for those interested
Post by: guest10167 on July 02, 2021, 05:16:01 PM
The mighty Jazz keeps surprising me.
During the last full tank of fuel, the trip computer showed 3.6 l/100 km for almost the whole time. My own calculation after filling up was 3.61 l/100 km (78.25 mpg). I mostly did commuting (50 & 70 kph) and only two short stints of motorway at 110. Always in B mode with econ on.
The surprising thing (to me) is, today the fuel consumption on the trip computer dropped to 3.5 two times, finally settling on 3.6 again, while the weather is slightly less warm and Econ is now switched off for the first time (which is noticeable when accelerating from standstill and lower speeds).
The previous tank gave me 966 kilometers of driving. With these economy figures, Iím tempted to go beyond 1000 km  8)
Title: Re: MPG for those interested
Post by: WelshBeauty on July 02, 2021, 08:43:35 PM
The mighty Jazz keeps surprising me.
During the last full tank of fuel, the trip computer showed 3.6 l/100 km for almost the whole time. My own calculation after filling up was 3.61 l/100 km (78.25 mpg). I mostly did commuting (50 & 70 kph) and only two short stints of motorway at 110. Always in B mode with econ on.
The surprising thing (to me) is, today the fuel consumption on the trip computer dropped to 3.5 two times, finally settling on 3.6 again, while the weather is slightly less warm and Econ is now switched off for the first time (which is noticeable when accelerating from standstill and lower speeds).
The previous tank gave me 966 kilometers of driving. With these economy figures, Iím tempted to go beyond 1000 km  8)
Somebody please tell me what 3.6 l/100 km means, as I don't live in Belgium.
Title: Re: MPG for those interested
Post by: Jocko on July 02, 2021, 08:53:36 PM
Somebody please tell me what 3.6 l/100 km means, as I don't live in Belgium.
3.6 Litres per hundred kilometres or 78.25 mpg as Pirre says in his post.
Title: Re: MPG for those interested
Post by: Jazzik on July 02, 2021, 08:56:15 PM
Somebody please tell me what 3.6 l/100 km means, as I don't live in Belgium.

Does the job: https://www.thecalculatorsite.com/conversions/fuelconsumption.php
Title: Re: MPG for those interested
Post by: peteo48 on July 03, 2021, 12:39:59 PM
Just a comment on mpg as against litres per 100 km.

I am pretty old but I genuinely can't my head round the litres per 100 km thing. I'm OK with a lot of metric stuff (I've moved on from pounds and ounces ;)).

I think the stumbling block for me is that it is "the other way round" - ie how much fuel to do a certain distance as opposed to mpg where it is the distance you get out of each unit of fuel. This means I can't perceive whether, say, 5 litres/100 km is economical or not.

Mental block.
Title: Re: MPG for those interested
Post by: Zaier on July 03, 2021, 03:37:41 PM
You're right, I was always used to km/l, the silly thing is that on Jazz it is not possible to switch from l/100km to km/l on the board computer, so I'm getting used to l/100km.

Fun fact EVs tend to use Wh/km or kWh/100km and not km/kWh.

Inviato dal mio LG-H815 utilizzando Tapatalk

Title: Re: MPG for those interested
Post by: peteo48 on July 12, 2021, 10:35:31 AM
If an hybrid consumes 4.4 and a non hybrid consumes 1 l more it makes me wonder if hybrids are really worth it. And even in an non hybrid you can save fuel by changing the way you drive

This reminds me of a pub debate from a couple of years ago. My pal who has a 24 kwh Nissan Leaf, said he "didn't like hybrids" on environmental grounds. His argument was they were the worst of all worlds involving all the dodgy mining processes to produce lithium ion batteries whist still emitting harmful CO2. There was also the issue of plug in hybrids which he said were even worse if used as long distance company cars because most of the time they would be powered by petrol but fuel consumption would be hit by having to lug a heavy battery around.

I don't necessarily agree. I think hybrids are, generally, more efficient and, given they take off from a standing start in EV mode they must be better for air quality.

I wonder what the truth actually is.
Title: Re: MPG for those interested
Post by: Jazzik on July 12, 2021, 04:25:09 PM
If an hybrid consumes 4.4 and a non hybrid consumes 1 l more...
A non hybrid 1 (one?) liter more...?
Just a simple example. Our previous car was a Honda Jazz Comfort Plus CVT. Search on Spritmonitor the actual measured average fuel consumption over at least 10,000 km. of that model. That's 6.11 l/100 km.
https://www.spritmonitor.de/de/uebersicht/18-Honda/169-Jazz.html?fueltype=2&vehicletype=1&constyear_s=2011&constyear_e=2015&power_s=69&power_e=79&minkm=10000&page=5
Not bad...
And now the Jazz e:HEV, same measurement: 4,43 l/100 km.
https://www.spritmonitor.de/de/uebersicht/18-Honda/1293-Jazz_Hybrid.html?fueltype=10&vehicletype=1&constyear_s=2020&minkm=7500&gearing=3
Difference a little more than 1 liter, right? To be precise: The e:HEV consumes an average of every 100 km. 1.68 liters of liquid gold less than the non-hybrid.

One more example: Our Jazz Comfort Plus CVT 2013 (non-hybrid) had an average consumption of 6.66 l/100 km measured over 4 years.
Its successor, our Toyota Yaris Hybrid 2017 (I know... a different car...) used exactly the same way, also measured over 4 years, has an average consumption of 4.89 l/100 km.

The difference: 1,77 l/100 km.
Title: Re: MPG for those interested
Post by: springswood on July 13, 2021, 08:07:38 AM
From what I can see Mercedes made diesel and petrol hybrid versions of the C and E class, plug in and non from 2015. They seem to make up about 20% of those for sale on AutoTrader. Also Peugeot and Citroen made diesel hybrids though they don't seem popular.

Title: Re: MPG for those interested
Post by: culzean on July 13, 2021, 10:49:31 AM
The problem with Diesels is still the emissions - which were laid bare by the 'cheat ' software scandal.  Long ago the Japanese said that as far as emissions were concerned Diesel was a 'dead end' technology.  The complicated and expensive equipment needed to reduce particulates and Nox emissions was becoming a lot of expense ( and regular servicing required £££'s ) for rapidly diminishing returns, + extra weight of diesel engines.  Neither VW or Audi feature in list of hybrids, and BMW only rarely... The Germans had firmly settled on Diesel,  and when diesels were 'outed' a few years ago decided to go straight to BEV and skip the hybrid bit..
Title: Re: MPG for those interested
Post by: E27006 on July 13, 2021, 05:09:47 PM
From what I can see Mercedes made diesel and petrol hybrid versions of the C and E class, plug in and non from 2015. They seem to make up about 20% of those for sale on AutoTrader. Also Peugeot and Citroen made diesel hybrids though they don't seem popular.
the first hybrids were sold in 1999/2000,  the Prius as we know it, became  mainstream in 2005/6,  Mercedes entered the market 10 years adrift of the Prius.
Mercedes self-reported secret collusion with other German  car makers, collusion between makers  to suppress or not introduce  technology that would reduce  exhaust pollution from vehicles,  the Courts have imposed fines on the car makers  for the illegal collusion, Mercedes  were exempt  from the fine for having self - reported the collusion
Title: Re: MPG for those interested
Post by: 150234 on July 14, 2021, 02:19:38 AM
First refuelling 465 miles, 30.65 litres so 69.3 mpg (car claimed 73 mpg).

Second refuelling 515 miles, 32.90 litres so 71.2 mpg (car claimed 75.1 mpg).

The "fibometer" appears to be about 5% optimistic - nothing new there!
71 mpg? That is phenomenal.

I couldnít even dream of such a figure. I have a  smile at 45mpg.
Title: Re: MPG for those interested
Post by: Roman on July 16, 2021, 11:54:42 AM
First refuelling 465 miles, 30.65 litres so 69.3 mpg (car claimed 73 mpg).

Second refuelling 515 miles, 32.90 litres so 71.2 mpg (car claimed 75.1 mpg).

The "fibometer" appears to be about 5% optimistic - nothing new there!
71 mpg? That is phenomenal.

I couldnít even dream of such a figure. I have a  smile at 45mpg.
If i not using climate control(only fan for ventilation using outside air) i can get around 90-100 MPG in town .
Climate control set to cooling greatly affects fuel economy in hot summer.

Title: Re: MPG for those interested
Post by: Kremmen on July 16, 2021, 01:38:37 PM
Because of my driving style, time of day, routes, I've always achieved more than the official figures.

In my current 1.8 torque converter auto Civic I'm averaging about 52mpg. The brochure combined is 44.8mpg

Same in my Lexus IS200, the official figure was 28 but I was averaging 32mpg.
Title: Re: MPG for those interested
Post by: peteo48 on July 16, 2021, 03:08:12 PM
Because of my driving style, time of day, routes, I've always achieved more than the official figures.

In my current 1.8 torque converter auto Civic I'm averaging about 52mpg. The brochure combined is 44.8mpg

Same in my Lexus IS200, the official figure was 28 but I was averaging 32mpg.

Impressive - does Jocko have a challenger for his crown ;)
Title: Re: MPG for those interested
Post by: Kremmen on July 18, 2021, 08:16:35 AM
Having looked again at the way the Jazz hybrid works I doubt I will be in the top 10.

Under about 10mph it can be electric, then 10 to 30 it's a mix and match but over 30 it's primarily engine.

99% of my weekly journey is motorway and fast A roads.
Title: Re: MPG for those interested
Post by: Whiteshark on July 18, 2021, 11:42:07 AM
As a new member, hello. The Jazz Hybrid we recently purchased belongs to my wife, who is the main driver. This is her 8th new Honda, all pretty faultless. However, I will probably drive more miles than her in it.
We part exchanged her Jazz Mk 3 Sport cvt, with 9k on the clock, really on my advice, because second hand car prices are very high, and we lost very little in depreciation.  She actually loved her Sport, but after driving this latest, I think she loves it more.
I have already driven it more, and I have to say I think it is an astonishing little vehicle.
To give some background, I drive a 2019 Mercedes S Class S400d, itself a brilliant car, and have just returned from driving 1372 miles to the Orkney Islands, so I do understand comfort and economy.
The day after we returned I took the Jazz to London and back in a day, some 485 miles, to collect an item, quite heavy, in order to give the Jazz some miles.
I filled up before and immediately after, and returned 63 mpg, with full aircon, motorway hold ups (many),  A roads,  and driving on acc at 70 mph. This is also a brand new car, 40 miles on the clock, and knowing Hondaís as I do, still very tight, so mpg will improve.
I am 6ft tall and I found the Jazz extremely comfortable to drive, with my only criticism being road noise on motorway at speed.
After watching the dash showing how it all works, which is pretty smart, I switched it off.
I have viewed many of the Video reviews, from motoring journalists and disagree with most, why do they love to put the Jazz down?.
In summary the Jazz ainít cheap, and we invariably buy the EX , but we are both very happy, particularly the versatility, which will be put to good use on a family holiday where the space loading beats the Merc .
Clearly in this day and age, an electric car would have been more ideal, but lack of charging ability, plus cost put us off. I also would not have risked a London return, but taking everything into account, and the whole Jazz Hybrid package, for our needs, 5 year warranty, 5 year servicingÖÖ just brilliant.
Title: Re: MPG for those interested
Post by: Jazzik on July 18, 2021, 12:51:08 PM
Having looked again at the way the Jazz hybrid works I doubt I will be in the top 10.

Your doubt is based on the way the Honda hybrid works? Whether the Jazz, with regard to fuel consumption, will be in the top 10, we will see in a while. But to give a first indication, which is based on too few cars to be reliable, here's a comparison between the "champion fuel-efficient hybrid", the new Toyota Yaris and the Jazz. This indication is based on data from "Spritmonitor" https://www.spritmonitor.de/en/ , measured over a minimum of 10,000 km. (just over 6200 miles).
The champion, the Yaris then has an average fuel consumption of 4.27 L/100 km (= 66.15 mpg) and the Jazz 4.44 L/100 km. (= 63.62 mpg).
Indeed, the Yaris shows (marginally) more economical, but as said: this is a first (unreliable) indication. In a year (or 2 years) we will get a more reliable picture.

Honda Jazz: https://www.spritmonitor.de/en/overview/18-Honda/1293-Jazz_Hybrid.html?fueltype=10&vehicletype=1&constyear_s=2020&minkm=10000&gearing=3

Toyota Yaris: https://www.spritmonitor.de/en/overview/49-Toyota/1287-Yaris_Hybrid.html?fueltype=10&vehicletype=1&constyear_s=2020&power_s=80&minkm=10000&gearing=3
Title: Re: MPG for those interested
Post by: jamjar on July 18, 2021, 01:07:48 PM
Having looked again at the way the Jazz hybrid works I doubt I will be in the top 10.

Under about 10mph it can be electric, then 10 to 30 it's a mix and match but over 30 it's primarily engine.

99% of my weekly journey is motorway and fast A roads.
As a new member, hello. The Jazz Hybrid we recently purchased belongs to my wife, who is the main driver. This is her 8th new Honda, all pretty faultless. However, I will probably drive more miles than her in it.
We part exchanged her Jazz Mk 3 Sport cvt, with 9k on the clock, really on my advice, because second hand car prices are very high, and we lost very little in depreciation.  She actually loved her Sport, but after driving this latest, I think she loves it more.
I have already driven it more, and I have to say I think it is an astonishing little vehicle.
To give some background, I drive a 2019 Mercedes S Class S400d, itself a brilliant car, and have just returned from driving 1372 miles to the Orkney Islands, so I do understand comfort and economy.
The day after we returned I took the Jazz to London and back in a day, some 485 miles, to collect an item, quite heavy, in order to give the Jazz some miles.
I filled up before and immediately after, and returned 63 mpg, with full aircon, motorway hold ups (many),  A roads,  and driving on acc at 70 mph. This is also a brand new car, 40 miles on the clock, and knowing Hondaís as I do, still very tight, so mpg will improve.
I am 6ft tall and I found the Jazz extremely comfortable to drive, with my only criticism being road noise on motorway at speed.
After watching the dash showing how it all works, which is pretty smart, I switched it off.
I have viewed many of the Video reviews, from motoring journalists and disagree with most, why do they love to put the Jazz down?.
In summary the Jazz ainít cheap, and we invariably buy the EX , but we are both very happy, particularly the versatility, which will be put to good use on a family holiday where the space loading beats the Merc .
Clearly in this day and age, an electric car would have been more ideal, but lack of charging ability, plus cost put us off. I also would not have risked a London return, but taking everything into account, and the whole Jazz Hybrid package, for our needs, 5 year warranty, 5 year servicingÖÖ just brilliant.
The warranty is 3 years. You have to pay to extend the warranty to 5 years.
Title: Re: MPG for those interested
Post by: equaliser on July 18, 2021, 01:16:16 PM
The warranty is 3 years. You have to pay to extend the warranty to 5 years.

All new Honda models have 5 year Honda Care, Servicing & Roadside Assistance at the moment - no extra payment.
https://www.honda.co.uk/cars/campaigns/five.html
Title: Re: MPG for those interested
Post by: Zaier on July 18, 2021, 01:18:59 PM
Having looked again at the way the Jazz hybrid works I doubt I will be in the top 10.

Under about 10mph it can be electric, then 10 to 30 it's a mix and match but over 30 it's primarily engine.

99% of my weekly journey is motorway and fast A roads.
As a new member, hello. The Jazz Hybrid we recently purchased belongs to my wife, who is the main driver. This is her 8th new Honda, all pretty faultless. However, I will probably drive more miles than her in it.
We part exchanged her Jazz Mk 3 Sport cvt, with 9k on the clock, really on my advice, because second hand car prices are very high, and we lost very little in depreciation.  She actually loved her Sport, but after driving this latest, I think she loves it more.
I have already driven it more, and I have to say I think it is an astonishing little vehicle.
To give some background, I drive a 2019 Mercedes S Class S400d, itself a brilliant car, and have just returned from driving 1372 miles to the Orkney Islands, so I do understand comfort and economy.
The day after we returned I took the Jazz to London and back in a day, some 485 miles, to collect an item, quite heavy, in order to give the Jazz some miles.
I filled up before and immediately after, and returned 63 mpg, with full aircon, motorway hold ups (many),  A roads,  and driving on acc at 70 mph. This is also a brand new car, 40 miles on the clock, and knowing Hondaís as I do, still very tight, so mpg will improve.
I am 6ft tall and I found the Jazz extremely comfortable to drive, with my only criticism being road noise on motorway at speed.
After watching the dash showing how it all works, which is pretty smart, I switched it off.
I have viewed many of the Video reviews, from motoring journalists and disagree with most, why do they love to put the Jazz down?.
In summary the Jazz ainít cheap, and we invariably buy the EX , but we are both very happy, particularly the versatility, which will be put to good use on a family holiday where the space loading beats the Merc .
Clearly in this day and age, an electric car would have been more ideal, but lack of charging ability, plus cost put us off. I also would not have risked a London return, but taking everything into account, and the whole Jazz Hybrid package, for our needs, 5 year warranty, 5 year servicingÖÖ just brilliant.
The warranty is 3 years. You have to pay to extend the warranty to 5 years.
It depends on the market and the MY.
In Italy the first year (2020) was with 8 years warranty included in the price, now they just give 3 years, 5 or 8 years are optional and you have to pay for it.
Title: Re: MPG for those interested
Post by: IanG on July 18, 2021, 01:21:09 PM
I think the inclusive 5 year warranty/servicing roadside assistance plan is dependent upon taking out Honda finance.
Title: Re: MPG for those interested
Post by: Whiteshark on July 18, 2021, 01:40:33 PM
Honda do change their offers. The extra 2 year warranty was negotiated in the package. The servicing plan was free if you took out a Honda finance plan, but we can pay off without penalty, other that a small interest charge after 6 months.
I think the offer now has changed again
Title: Re: MPG for those interested
Post by: Kenneve on July 18, 2021, 04:18:23 PM
Yes,I took the Honda Finance package, in order to obtain the 5 years free service and will paying it off in full after 6 months.
Actual cost is peanuts, compared with the full cost of 5 years service.
Title: Re: MPG for those interested
Post by: Jazzik on July 18, 2021, 07:50:24 PM
Here in Poland the standard Honda warranty for cars is 3 years.
If the car insurance is taken out at Helvetia through Honda (competitive price), the warranty is extended to 5 years or a maximum of 300.000 km!!! (186,000 miles!!!).
It seems they (the importers) do it differently everywhere...
Title: Re: MPG for those interested
Post by: jamjar on July 18, 2021, 09:56:11 PM
The warranty is 3 years. You have to pay to extend the warranty to 5 years.

All new Honda models have 5 year Honda Care, Servicing & Roadside Assistance at the moment - no extra payment.
https://www.honda.co.uk/cars/campaigns/five.html
When I was purchasing my car, I got the 5 years free servicing & road side assistance. When enquiring about the warranty I was told the car would come with three years warranty & you would have the option to extend it to 5 years at any time for an additional payment. see link below:
https://www.honda.co.uk/cars/owners/extended-guarantee-old.html
Title: Re: MPG for those interested
Post by: Jeff15 on July 19, 2021, 10:42:30 AM
Yesterday I drove from Lichfield to Stratford upon Avon with air-con all the time, with mostly motorway driving I averaged 64.1 mpg.
Title: Re: MPG for those interested
Post by: Jocko on July 19, 2021, 11:28:59 AM
Despite my best hypermiling techniques I cannot manage that on a regular basis. Need to get a Mk 4.
Title: Re: MPG for those interested
Post by: Jazzik on July 19, 2021, 12:33:10 PM
Yesterday I drove from Lichfield to Stratford upon Avon with air-con all the time, with mostly motorway driving I averaged 64.1 mpg.

This kind of "averages" is very nice, but means nothing at all. The only way to determine an average consumption is to measure (not read the bc!) over a long(er) period, a year or more and under all weather and traffic conditions.
After a long(er) time you will see a realistic average fuel consumption. I recommend to use for example https://www.spritmonitor.de/en/
Title: Re: MPG for those interested
Post by: Mellorshark on July 19, 2021, 01:49:10 PM
Having looked again at the way the Jazz hybrid works I doubt I will be in the top 10.

Under about 10mph it can be electric, then 10 to 30 it's a mix and match but over 30 it's primarily engine.

99% of my weekly journey is motorway and fast A roads.
Don't be fooled by Honda giving an easy to understand explanation using speed.  It depends on load. I have had it run in EV mode at 65 mph; downhill on the motorway. The best results come from a light right foot when accelerating.
Title: Re: MPG for those interested
Post by: 150234 on July 19, 2021, 03:12:14 PM
Despite my best hypermiling techniques I cannot manage that on a regular basis. Need to get a Mk 4.
Out of interest, do you try to get the highest MPG possible to mostly save money, or is it like game/compeition to you to try and do as best you can?

Personally, I haven't got the patience for it so I just drive as normal and then just fill up when the fuel light comes on + about 40 miles.
Title: Re: MPG for those interested
Post by: Jocko on July 19, 2021, 07:05:44 PM
Out of interest, do you try to get the highest MPG possible to mostly save money, or is it like game/compeition to you to try and do as best you can?
It is all a game. I am retired, I am seldom in a hurry to get anywhere and it adds interest to my driving. My wife goes on about "Bonnie Scotland? All I ever see is the back of one truck or another.".
Title: Re: MPG for those interested
Post by: Bristol_Crosstar on July 20, 2021, 09:16:58 AM
I have noticed that driving with the ECO button on I get around 10% extra mpg and the performance is still good. I was getting around 65mpg (according to the dash figure) when I first had the car but with the ECO on I'm getting 70+
Title: Re: MPG for those interested
Post by: Jocko on July 20, 2021, 08:16:06 PM
Some days I can get Hybrid mpg with my Mk 1. This was for a run from Cowdenbeath via Mossmorran, Auchtertool to Kirkcaldy. All country roads. No AC (don't have any) but I did have the windows wide open.

(https://i.imgur.com/0uh5KLl.jpg)

Think I need to dust my dash and instruments!
Title: Re: MPG for those interested
Post by: PTJAZZ on July 28, 2021, 08:27:57 PM
I have now 1350 Km.

MPG BC 3.2 L real 3.44 L  around 82.12 mpg  (Sprit Monitor)

Autonomy more than  1150 Km
Title: Re: MPG for those interested
Post by: Jocko on July 29, 2021, 04:23:21 PM
I too use Sprit Monitor. That is where the number beside my avatar is derived.
Title: Re: MPG for those interested
Post by: Roman on July 29, 2021, 05:06:28 PM
I to can get close to this mileage of 3.2l but now too hot (34įC and 70% humidity) .
My last tank refill average 3.89l (using a/c) (904km from ful to empty tank light come up with 45km to empty on screen. (According to user manual should be around 5l in tank) refilled 36l, i think our gas stations cheating.....
Morning trips without a/c ~ 10km with speed up to ~40km/h i getting readings from BC 3.1l/100km.
4 months ago i have issues with braking system
the brake pads wedged sometimes, a couple of times in traffic jams I heard a rumble from behind, I thought that the truck was slowing down nearby, until I heard the same rumble when I was turning around in an empty parking lot, I went to the service center, they told me that they hadn't found anything, but after that the fuel consumption became  decrease.
On trips that not shorter then 7 km with speed up to 40km/h on flat road it's possible.
Japanese Fit e:HEV in specs have WLTP test and JC08 test results, using JC08 test pattern (if someone interested this can be found in the net) car can show consumption 2.8l/100k in town.
Title: Re: MPG for those interested
Post by: 150234 on July 29, 2021, 05:42:39 PM
So if I drive carefully at 70mph I can get 45.2 mpg average which isn't bad for a 17 year old car with several problems. Note that this was at night in the rain (added resistance from the water) main beams on and I had the demisters on due to steaming up so there was some electrical load on the car, not to mention the stereo that I have on fairly loud.

For those interested, at 110mph with the same electrical load the mpg drops down to 19.5mpg.
Title: Re: MPG for those interested
Post by: nowster on July 30, 2021, 10:07:22 AM
For those interested, at 110mph with the same electrical load the mpg drops down to 19.5mpg.
I'll pretend we didn't hear that.  ;D
Title: Re: MPG for those interested
Post by: richardfrost on July 30, 2021, 11:24:23 AM
For those interested, at 110mph with the same electrical load the mpg drops down to 19.5mpg.

Interested and impressed that the old jalopy can get to 110mph.  8)
Title: Re: MPG for those interested
Post by: 150234 on July 30, 2021, 11:39:08 AM
For those interested, at 110mph with the same electrical load the mpg drops down to 19.5mpg.

Interested and impressed that the old jalopy can get to 110mph.  8)
Foot flat to the floor, sitting at around 6000rpm and shaking like a dog, but other than that it cruises comfortably. If you anchor on quickly though for a junction you can hear and feel the brake fading.
Title: Re: MPG for those interested
Post by: John Ratsey on August 04, 2021, 07:01:00 PM
A round trip today of a bit over 30 miles each way mainly on an A road where about 2/3rd of the distance has a 50 mph limit. The fibometer claimed 83.1 mpg on the outgoing leg and 79.3 mpg on the return. The latter included aircon use and a very small headwind. That's an average of 81.2 mpg but I find the fibometer to be nearly 5% optimistic which reduces the average to 77.1 mpg.
Title: Re: MPG for those interested
Post by: Jeff15 on August 13, 2021, 09:19:22 AM
I can get more mpg without using the eco mode, I am getting at least 67mpg with which I am more than happy.
Title: Re: MPG for those interested
Post by: Derkie54 on August 14, 2021, 10:51:55 AM
Had my Mk4 for 1 week now and first run on open B roads gave a reading of 79.9 mpg
Title: Re: MPG for those interested
Post by: PTJAZZ on August 17, 2021, 06:25:39 PM
Already 2000 Km and the consumption still 3.2L average. Photo attached during the trip.
Title: Re: MPG for those interested
Post by: nowster on August 18, 2021, 10:59:24 AM
Already 2000 Km and the consumption still 3.2L average. Photo attached during the trip.
Wow! 88mpg.
Title: Re: MPG for those interested
Post by: JimSh on August 18, 2021, 11:07:18 AM
Already 2000 Km and the consumption still 3.2L average. Photo attached during the trip.
Wow! 88mpg.
73.5 mpg. Still very impressive. :)
Edit my mistake the conversion gave US gallons.
88 mpg right enough.
Title: Re: MPG for those interested
Post by: PTJAZZ on September 05, 2021, 07:28:52 PM
I was challenge to do 1000 Km with one tank.

Challende accepted.

Done already 1003 Km with this tank, still 225 Km autonomy ( 3 bars fuel left) and BC indicate 3.0 L average.

Long term average in 3325 Km 3.2L

Does anibody say plug-in or electric several thousand EURO  more expensive
Title: Re: MPG for those interested
Post by: nowster on September 05, 2021, 07:48:28 PM
That's impressive!

My most recent fill (35.0 litres) was after 446 miles (717km). Two bars were showing on the fuel gauge and about 50 miles range left.

Long term average is 60.3 MPG. (4.683 L/100km)

I live in a hilly area.
Title: Re: MPG for those interested
Post by: 150234 on September 05, 2021, 08:24:24 PM
So this week (Midnight on Sunday 05/09/21 to 12/09/21) I will do over 500 miles (mostly motorway) in my Jazz which will be interesting. 500 miles is usually 1.5 fill ups depending on how I drive.

It will be 500 miles minimum as long my planned week goes as planned and could be more depending on a few things. Due to my recent relationship situaiton change (ie. new parter lives futher away) it's likely that 400mi a week could become the norm, which is a fair week for an 18 year old 137,000mi Jazz. I have faith though, it's done this before so it can do it again.
Title: Re: MPG for those interested
Post by: Zaier on September 05, 2021, 08:44:00 PM
I was challenge to do 1000 Km with one tank.

Challende accepted.

Done already 1003 Km with this tank, still 225 Km autonomy ( 3 bars fuel left) and BC indicate 3.0 L average.

Long term average in 3325 Km 3.2L

Does anibody say plug-in or electric several thousand EURO  more expensive
Impressive, i did two time 989km but with 0 bars left, so I didn't felt comfortable risking 1000km, my best tank was 26km/l with AC use when needed.
Title: MPG for those interested
Post by: sportse on September 06, 2021, 12:54:14 PM
Over nearly 2,000 miles Iím averaging around 54-58mpg.

Not bad as most of my driving is 70mph motorway on long trips. It compares to a diesel hatchback where my long term mpg was 44-47mpg on the same journeys. So about 10mpg more using cheaper fuel.

As soon as I drop below the usual 70mph cruising speed the mpg shoots up.

I did a 30 mile motorway trip recently, about half at up to 70mph and half fixed at a set 40/50mph due to roadworks. Mpg for the whole trip was 70! That was just driving normally with the rush hour traffic.
Title: Re: MPG for those interested
Post by: Roman on September 06, 2021, 08:41:17 PM
Impressive, i did two time 989km but with 0 bars left, so I didn't felt comfortable risking 1000km, my best tank was 26km/l with AC use when needed.
[/quote]
Not understand  is last bar on meter also disappears ? :o
On my Jazz low fuel warning starts when ~5l left with 50km left to 0
When 0 km remaining appears on meter I can refuel 36l
So remaining fuel is 4l
Title: Re: MPG for those interested
Post by: Zaier on September 07, 2021, 08:42:40 AM
Last bar disappears also, I've filled up 38L after that.
I thought that the estimated range left was a little conservative as on Toyotas, so I've tried to run after that l.
I did 20-30km with 0 range, and after that went to 0 bars left on that tank, so i think it's keeping just 50-60km of margin after 0 range left.
Title: Re: MPG for those interested
Post by: Roman on September 07, 2021, 10:04:06 AM
I was challenge to do 1000 Km with one tank.

Challende accepted.

Done already 1003 Km with this tank, still 225 Km autonomy ( 3 bars fuel left) and BC indicate 3.0 L average.

Long term average in 3325 Km 3.2L

Does anibody say plug-in or electric several thousand EURO  more expensive
Awesome!!!
I canít get 3.2l average- to many tailgaters and aggressive drivers on our roads, my best last trip 120km - 3.1l/100km with AC set to 22 C (but the sun was already low, so the air conditioner did not waste a lot of energy, outside it was 31 degrees Celsius ) with speed 70-90km/h

Title: Re: MPG for those interested
Post by: 150234 on September 07, 2021, 05:48:57 PM
For those interested, it's possible to do 72 miles at 43.5mpg before it runs out of puff and you have to class the AA as I delicately tested the other day.

Title: Re: MPG for those interested
Post by: Roman on September 08, 2021, 06:50:04 PM
I known it's not average consumption
(https://i.ibb.co/YD8VFb3/20210908-194519-HDR.jpg)
And i cheating  :), when i startet this trip battery have 60% of charge and all road descents slightly, previus trip other way same road and speed limit.
No AC usage only ventilation that takes air from outside.
(https://i.ibb.co/HghJZHh/20210908-194537-HDR.jpg)
That average mpg from last trip A reset on full tank refill.
Title: Re: MPG for those interested
Post by: sportse on September 08, 2021, 08:17:34 PM
I happened to be rereading the Auto Express review of the normal JazzÖ somehow they managed to average 42mpg! Less than the 50+ they got in a later review of the Crossstar.

I donít know what they did but maybe itís a misprint - no one else seems to have got mileage that low.
Title: Re: MPG for those interested
Post by: Roman on September 08, 2021, 08:35:26 PM
That possible if on review they drive aggressively or very short trips,  short trips especially when ICE is cold may give low MPG easily.
Title: Re: MPG for those interested
Post by: Expatman on September 08, 2021, 11:17:17 PM
I have been forced to the conclusion that test drivers for auto magazines etc. do not once consider the reality of the vehicle they are testing. All are rated against their misguided belief in how a Porsche should be driven and perform. I understand they are there to expose weaknesses and areas of concern but to not appreciate the advantages of each car or try and understand what it was designed to accomplish is a real failing on their part. We are all interested in basics like 0-60, top speed, cornering etc. but only as basic parameters; mpg driven as intended and ride comfort and refinement are at least as important. Why, for instance, donít they report on ride height - a major factor in those looking at Crossover SUVís ?
Title: Re: MPG for those interested
Post by: 150234 on September 09, 2021, 04:03:53 PM
I have been forced to the conclusion that test drivers for auto magazines etc. do not once consider the reality of the vehicle they are testing. All are rated against their misguided belief in how a Porsche should be driven and perform. I understand they are there to expose weaknesses and areas of concern but to not appreciate the advantages of each car or try and understand what it was designed to accomplish is a real failing on their part. We are all interested in basics like 0-60, top speed, cornering etc. but only as basic parameters; mpg driven as intended and ride comfort and refinement are at least as important. Why, for instance, donít they report on ride height - a major factor in those looking at Crossover SUVís ?
I disagree, MPG and comfort wouldn't be anywear near the top of my list when looking at a car for myself. My current (also first car) was bought cheap for insurnace purposes and for practice.

The second car (in a few weeks) is likely to be on of the V8 Supercharged Jaguar XF's and let me tell, the comfort or MPG wasn't on my list when choosing it. 0-60, noise and how quickly I can make rubber become smoke were my top 3.
Title: Re: MPG for those interested
Post by: Expatman on September 09, 2021, 04:44:07 PM
You are just the person many car testers are writing for!
I would suggest however that you are in the minority and the ability to make smoke is far, far down the list for most drivers in 2021.
Title: Re: MPG for those interested
Post by: Roman on September 09, 2021, 04:57:17 PM
Well someone looking for 0-60, smok and noise should not look on hybrid cars, purpose to have hybrid car  is to get maximum fuel economy, have comfortable ride, and save planet from excessive co2 build up.
So car tester should be able to test ability of hybrid car to give MPG and show how efficient this car can be, 0-60 and breaking disrance from 60 also intresting that sometimes can save life.
Title: Re: MPG for those interested
Post by: Jazzik on September 09, 2021, 05:20:32 PM
I disagree, MPG and comfort wouldn't be anywear near the top of my list when looking at a car for myself. My current (also first car) was bought cheap for insurnace purposes and for practice.

The second car (in a few weeks) is likely to be on of the V8 Supercharged Jaguar XF's and let me tell, the comfort or MPG wasn't on my list when choosing it. 0-60, noise and how quickly I can make rubber become smoke were my top 3.


(https://images.partydelights.co.uk/CUTO/33/8/front/v1/pop/2.jpg)
Title: MPG for those interested
Post by: sportse on September 09, 2021, 05:34:58 PM
The mk4 Jazz hybrid has the same 0-60 as the mark 1 VW Golf GTI or the Mazda MX5 Miata.

Itís also the same 0-60 as the current VW Up GTI, so not a slow car at all.

My last car was a tuned 180hp/400Nm hatchbackÖ the Jazz is just as fast at real world speeds and actually faster at the lower end.
Title: Re: MPG for those interested
Post by: Jazzik on September 09, 2021, 06:28:25 PM
But for noise and how quickly it can make rubber become smoke it for sure loses with the types of car 150234 would go for.
Maybe a TROLLeybus :P would be something for 150234... https://www.tbus.org.uk/home.htm
Title: Re: MPG for those interested
Post by: jamjar on September 11, 2021, 03:56:09 PM
First refuelling 465 miles, 30.65 litres so 69.3 mpg (car claimed 73 mpg).

Second refuelling 515 miles, 32.90 litres so 71.2 mpg (car claimed 75.1 mpg).

The "fibometer" appears to be about 5% optimistic - nothing new there!

Just checked on my Honda+App, one 24 mile journey showing 79.9 mpg (Kendal in Cumbria to Morecambe). Any idea on the accuracy of this figure on this app?
Title: Re: MPG for those interested
Post by: sportse on September 11, 2021, 04:28:14 PM
Seems pretty accurate- on long motorway trips Iím getting maybe 55mpg but as soon as the speed drops the mpg goes up.

I did a trip on the M25/M4 in rush hour, 25 miles at maybe an average 50mph & got 70mpg.

Coming back later with no traffic and a steady 70mph average the mpg was normal around 55mpg.

Trips off the motorway at up to 60mph and getting around 60mpg.

So for me, very roughly long distance average speed gives:

70mph - 50+mpg

60mph - 60mpg

50mph - 70mpg
Title: Re: MPG for those interested
Post by: John Ratsey on September 12, 2021, 06:05:12 PM
Just checked on my Honda+App, one 24 mile journey showing 79.9 mpg (Kendal in Cumbria to Morecambe). Any idea on the accuracy of this figure on this app?
The My Honda+ app shows exactly the same mpg numbers as the Trip Computer function on the big screen. I assume that these numbers have the same optimistic bias as the miles per refill otherwise the overall numbers wouldn't add up. I'm currently on 4.77% optimism bias.

The claimed 79.9 mpg Kendal to Morecambe is plausible as I've found that the hybrid system is very sensitive to any height difference between start and end points. Kendal is about 200ft above sea level and any downhill journey increases the proportion of the time when the car can be running on battery. Was it a dry day? I've found that wet roads cause a surprising reduction in the mpg.
Title: Re: MPG for those interested
Post by: Derkie54 on September 12, 2021, 07:03:13 PM
First refuelling 465 miles, 30.65 litres so 69.3 mpg (car claimed 73 mpg).

Second refuelling 515 miles, 32.90 litres so 71.2 mpg (car claimed 75.1 mpg).

The "fibometer" appears to be about 5% optimistic - nothing new there!

Just checked on my Honda+App, one 24 mile journey showing 79.9 mpg (Kendal in Cumbria to Morecambe). Any idea on the accuracy of this figure on this app?

On my first trip on fairly clear and level B roads I also got a reading of 79.9 mpg.
Title: Re: MPG for those interested
Post by: jamjar on September 12, 2021, 09:58:51 PM
Just checked on my Honda+App, one 24 mile journey showing 79.9 mpg (Kendal in Cumbria to Morecambe). Any idea on the accuracy of this figure on this app?
The My Honda+ app shows exactly the same mpg numbers as the Trip Computer function on the big screen. I assume that these numbers have the same optimistic bias as the miles per refill otherwise the overall numbers wouldn't add up. I'm currently on 4.77% optimism bias.

The claimed 79.9 mpg Kendal to Morecambe is plausible as I've found that the hybrid system is very sensitive to any height difference between start and end points. Kendal is about 200ft above sea level and any downhill journey increases the proportion of the time when the car can be running on battery. Was it a dry day? I've found that wet roads cause a surprising reduction in the mpg.

Yes it was a dry day, I did notice EV mode was on on some points driving at 67 mph as well. The downhill drive as you mention is more likely to give a better mpg.
Title: Re: MPG for those interested
Post by: Neil Ives on September 12, 2021, 10:53:54 PM
Hybrid economy  :D
Title: Re: MPG for those interested
Post by: jamjar on September 13, 2021, 02:55:58 PM
 :) Now that is economy!
Title: Re: MPG for those interested
Post by: Neil Ives on September 13, 2021, 02:59:22 PM
A longer journey, mostly on motorway:
Title: Re: MPG for those interested
Post by: 150234 on September 17, 2021, 02:12:42 AM
But for noise and how quickly it can make rubber become smoke it for sure loses with the types of car 150234 would go for.
Maybe a TROLLeybus :P would be something for 150234... https://www.tbus.org.uk/home.htm
I mean, I would expect the Jaguar XF 3.0 V6 280hp and 600nm of torque to beat a Golf, and definitely a Jazz.

Did I mention RWD for them mini roundabouts.
Title: MPG for those interested
Post by: sportse on September 17, 2021, 06:30:37 AM
I mean, I would expect the Jaguar XF 3.0 V6 280hp and 600nm of torque to beat a Golf, and definitely a Jazz.

Did I mention RWD for them mini roundabouts.

Assuming a perfect Jaguar launch every stop (left foot braking to build up the revs and turbo, and a bit of wheel spin,which will wear the transmission/etc), itís actually only 0.8 seconds faster to 37mph than a crosstar:

Duel: Honda Jazz IV Crosstar e:HEV vs Jaguar XF 3.0 D S (https://zeperfs.com/en/duel8682-2909.htm)

Whereas all the Jazz driver has to do is calmly press the accelerator to launch. The Jaguar driver has to dial up the revs and find traction every time perfectly to get that launch performance. Just pressing the accelerator with no revs build up first in many diesels adds 1 second to the 0-60mph time.

With lots of mini roundabouts, the Jazz driver actually has a real chance of winning against a 280hp diesel XF!

In a drag race to 30mph, from idle, the 110hp Jazz should beat the 280hp XF. It has over 500kg less weight, and 250Nm available from zero revs.

You even get a nice noise with fake gear shifts in the Mk4 under full acceleration:



(For all points - Professional Driver/Closed Course obviously)
Title: Re: MPG for those interested
Post by: 150234 on September 17, 2021, 09:59:08 PM
I mean, I would expect the Jaguar XF 3.0 V6 280hp and 600nm of torque to beat a Golf, and definitely a Jazz.

Did I mention RWD for them mini roundabouts.

Assuming a perfect Jaguar launch every stop (left foot braking to build up the revs and turbo, and a bit of wheel spin,which will wear the transmission/etc), itís actually only 0.8 seconds faster to 37mph than a crosstar:

Duel: Honda Jazz IV Crosstar e:HEV vs Jaguar XF 3.0 D S (https://zeperfs.com/en/duel8682-2909.htm)

Whereas all the Jazz driver has to do is calmly press the accelerator to launch. The Jaguar driver has to dial up the revs and find traction every time perfectly to get that launch performance. Just pressing the accelerator with no revs build up first in many diesels adds 1 second to the 0-60mph time.

With lots of mini roundabouts, the Jazz driver actually has a real chance of winning against a 280hp diesel XF!

In a drag race to 30mph, from idle, the 110hp Jazz should beat the 280hp XF. It has over 500kg less weight, and 250Nm available from zero revs.

You even get a nice noise with fake gear shifts in the Mk4 under full acceleration

But will the rear end slide out in the mk4? I think not.

5.9 seconds to 60mph will thoroughly slap the mk4 about the place, any day of the week. As for 0-37mph, I don't remember seeing that test on Top Gear. Who races from idle? Like who?

How exactly would a Jazz beat an XF around mini roundabouts? I just have to boot the throttle and around she goes, I'm going back where I came from in less than a second.

As for torque, well 600nm at 2000rpm will be lovely.

The mk4 just doesn't compare, in anyway.
Title: Re: MPG for those interested
Post by: Jazzik on September 17, 2021, 10:09:01 PM
.
.
(https://www.cheesebuerger.de/smiliegenerator/vorschau/43432.png)
.
.
Title: Re: MPG for those interested
Post by: Kremmen on September 18, 2021, 04:44:11 AM
I've completed 2 of my regular weekly journeys along the M4 and fast A roads and my average mpg is just under 70mpg. I can't see that getting any higher.

Probably lower when the M4 returns to 70mph
Title: MPG for those interested
Post by: sportse on September 18, 2021, 05:45:05 AM
75+mpg the other day :) just driving normally on 40/50/60mph roads.

Even on fairly short trips Iím getting 50+. My Toyota hybrid was over 10mpg less on the same roads.

(https://uploads.tapatalk-cdn.com/20210918/f1e734516641fd40bbc6b89e7311e5c6.jpg)
Title: MPG for those interested
Post by: sportse on September 18, 2021, 09:49:18 AM
Iím finding cruising speed to have the biggest effect on mpg.

Today I had a 25 mile trip, from cold and having to demist the car I still got over 64mpg on country roads mostly 30/40/50!

For comparison the Auris hybrid I used to have would have struggled to hit even 44mpg on that trip.

For me, a steady 50mph cruise either through roadworks or open country roads with that limit consistently gets me over 70mpg.

Whereas at 70mph Iím consistently getting lower/mid fifties. Compared to my Auris hybrid that did mid forties on the same roads.

Itís a very impressive engine/motor setup in the Jazz.
Title: Re: MPG for those interested
Post by: nowster on September 19, 2021, 02:15:10 PM
A leisurely trip from Manchester to NW Wales (about 150 miles) with cruise control set to 60mph. A mixture of motorway, dual carriageway, A roads and B roads.

I let ACC tag me along behind lorries on max follow distance, etc. The intent was to have the drive to be low stress, leaving me to wind down whilst listening to some podcasts and a bit of radio.

In my Mk2 I'd be needing to refuel about half way to allow me to make the return trip without stopping. I started with a nearly full tank. The range remaining is 396 miles.
Title: Re: MPG for those interested
Post by: Kremmen on September 20, 2021, 07:24:25 AM
I've found something odd ......

When I turned off yesterday my trip B was showing 68.7 mpg. I went out this morning, powered up, and trip B was showing 67.4 mpg.

When I powered up, the engine didn't fire up so no petrol being used.

I did the same again, powered off and on again and trip B was now down to 66.7 mpg.

I wonder what it's doing ?

Title: Re: MPG for those interested
Post by: sportse on September 20, 2021, 10:31:58 AM
I've noticed something similar when I've been sitting in the car not going anywhere setting things up - but in my case the petrol engine was cycling on/off as needed a few times to keep the battery charged.

It might be that it is assuming that it will shortly be running the engine warm up cycle whenever it's turned on, so taking that into account?
Title: Re: MPG for those interested
Post by: Kremmen on September 20, 2021, 11:26:08 AM
I've recently completed a 60 mile round trip so the batteries are OK.

As you say, I expected the MPG drop during stationary setup as the engine did periodically kick in, as expected, during my couple of hours setup.

This morning I did turn off the heating/AirCon as that will fire up the engine.

I powered up, the engine did not fire up but the MPG dropped anyway. It's doing or trying to do something clever because the power is on.
Title: Re: MPG for those interested
Post by: Roman on September 20, 2021, 12:20:18 PM
Maybe now car computer countin idling electricity consumption in EV mode - that something like 300w
In Jazz 2021 that consumption not counted so MPG not decreasing when i idling in EV mode.
Title: Re: MPG for those interested
Post by: Kremmen on September 20, 2021, 12:57:44 PM
I'll find out how accurate it is when I next brim it then do the maths, litres in v miles covered.

When that happens my Spritmonitor will change from -- to something realistic.

Not for a while though at 60 miles per week.
Title: Re: MPG for those interested
Post by: Roman on September 22, 2021, 06:51:48 AM
Sorry for off topic
Today changed several times l/100km to MPG and back without mooving car and found that our MY21 infotainment have glitch  ;)
Each time i changed measured units infotainment duplicated  trip A from last trip A .....
Can someone check if this happens not only with my infotainment ?
Title: Re: MPG for those interested
Post by: 150234 on September 22, 2021, 12:32:33 PM
Can anway tell me why in a mk1 Jazz at 70mph in top gear I can only manage 41mph when trying to be as gently as possible? That seems a bit poor to me, I should probably check tyre pressures as I haven't done in a while, what's everyone running?

One thing I will say though, my particular Jazz isn't very efficient as it has the worst tyre QwikFit had with an E rating for fuel economy, it's heavily loaded as it has quite a lot of stuff in it for work which add to the total weight and it's also got quite draggy gearbox which does have a few issues.

Also, the car is about to get to 140,000 miles in the next month or so and considering I bought it with two owners at 112,122 who had both babyied the car around the city with a few mile per year over the previous 17 years, I reckon that the engine has a fair few hours on it also so is likely suffering from wear.
Title: Re: MPG for those interested
Post by: John Ratsey on September 22, 2021, 06:22:26 PM
Can anway tell me why in a mk1 Jazz at 70mph in top gear I can only manage 41mph when trying to be as gently as possible?
This is the Mk 4 Jazz forum so we Mk 4 Jazz owners hope to get better mpg than your Mk 4 Jazz. In addition to the factors you have mentioned, I expect that the engine is running outside of its most efficient zone (particularly if it's 1.2 L). What's the engine rpm at 70 mph?

Getting back to the Mk 4, I got a claimed 123.9 mpg on a 6 mile trip today. However, the car was assisted by gravity - the start was about 100m higher than the end. I forgot to note the mpg for the trip in the opposite direction but it would have been somewhat lower but it highlights the effect of height difference on individual trips.
Title: Re: MPG for those interested
Post by: Roman on September 22, 2021, 06:51:11 PM
Can anway tell me why in a mk1 Jazz at 70mph in top gear I can only manage 41mph when trying to be as gently as possible?
This is the Mk 4 Jazz forum so we Mk 4 Jazz owners hope to get better mpg than your Mk 4 Jazz. In addition to the factors you have mentioned, I expect that the engine is running outside of its most efficient zone (particularly if it's 1.2 L). What's the engine rpm at 70 mph?

Getting back to the Mk 4, I got a claimed 123.9 mpg on a 6 mile trip today. However, the car was assisted by gravity - the start was about 100m higher than the end. I forgot to note the mpg for the trip in the opposite direction but it would have been somewhat lower but it highlights the effect of height difference on individual trips.

Maximum MPG that claimed on Honda Japan site for  e:HEV FIT is 108 MPG or 2.63l/100km or 38.5km/l in JC08 testing cycle/ but WLTC only 3.57l/100km or 79 MPG
(https://i.ibb.co/NLNb1hf/FIT-spec.jpg)
right side of screenshot for Japanese 1.3l petrol FIT with variator
The following are selected parameters of the JC08 driving schedule:

Duration: 1204 s
Total distance: 8.171 km
Average speed: 24.4 km/h (34.8 km/h excluding idle)
Maximum speed: 81.6 km/h
Load ratio: 29.7%
(https://i.ibb.co/yBx21F7/JC08.png)
Today seen 2.8l/100km without gravity help but i added air pressue in tires - now is 38 psi front and 36 psi back this pressure recomended if driver frequently driving with speed that higer then 160km/h ? to reduse tire heating.
Title: Re: MPG for those interested
Post by: Kremmen on September 23, 2021, 04:39:08 AM
No matter how I'm driving I've only ever seen 2 readouts on the 'instant mpg' bar.

It either reads somewhere around 35mpg (midway between zero and the centre marked 70mpg) or 140mpg when presumably the engine is off.

Seems sort of pointless if that's the norm.

Title: Re: MPG for those interested
Post by: sportse on September 23, 2021, 06:07:55 AM
Yes, Iíve stopped looking at the instant mpg bar as it doesnít seem to be much use.

A eco/power bar like other hybrid cars have showing percent of power used would be more useful as you could vary the accelerator to get more mpg.

Mine also seems a bit slow to react, so not really instant mpg.
Title: Re: MPG for those interested
Post by: sportse on September 24, 2021, 07:28:42 AM
An interesting trip last week of about an hour stopping once without turning off the engine. Split nearly 1/3 motorway, 1/3 urban and 1/3 country roads.

Averaging 64mpg. Without the motorway section then Iím sure mpg would be over 70.
Title: Re: MPG for those interested
Post by: Kremmen on September 24, 2021, 07:37:04 AM
On my last Heathrow area to Reading return journey I hit Eco and took it easy but I still can't quite crack 70mpg. Very close at 68 though.

Looking at previous journeys Eco did almost nothing. Unlike the Civic I didn't notice any change to throttle response or climate control performance.
Title: Re: MPG for those interested
Post by: Roman on September 24, 2021, 09:14:30 AM
Hi Kremmen
About ECON it hass effect on climate controll - in hot day if you using climate control without ECON the climate control can blow air with high speed, but when you press ECON button theclimate control  air blower speed reduces and cabin temperature not keeping always same temperature that you choise but can rise if you cooling cabing  and recirculation for air choisen (the speed near knob may remain same but you can hear that speed of blower reduced)
About acceleration with ECON pressed - if i gentle on accelerator pedal and i pushing ECON i can feel little reduction in power  (lets say it`s like if you drive an old car with 1.0l naturaly aspirated engine uphill and when acelerating  hitting air con on)
About regen braking without ECON - its more powerfull from my observation, when i removing my foot from accelerator and when pressing braking pedal .
This make sense because bigger economy is not when regen braking used but when car glades (no aceleration and no braking used) that reason to use ECON and B mode in town, when you gentle on accelerator you can catch its position where regen is almost not applied, you can check this when you driving downhill but becarefull when you in B mode and releasing accelerator fully you  speed redusing fast like you pressing  brak pedal  but stop light not activated !!!
But  if you doing small trips without A/C (lets say 6-8km) in town with speed up to 40km/h  and gentle with accelerator, allowing to car reduce speed slowly without hard regen braking if you need to stop you can get same fuel economy as with ECON pressed.
About fuel economy when my Jazz new it suffered firs 2 month from brak pads dragg. The pads was new and i almost not used them, several times i heared noise from rear of car when started to move (noise like from heavy car that braking hard but there was no car near me) I let to honda service check car -they told me that they not found something wrong with braking system but after this check that wooping noise from rear of car not came back and fuel economy started to rise .
Title: Re: MPG for those interested
Post by: Roman on September 25, 2021, 03:23:12 PM
Play with obd2 car scanner
(https://i.ibb.co/tYNPhLY/20210925-171100-HDR.jpg)
I not unedstand Honda
They included power meter on new HR-V e:HEV
But Jazz/FIT not get this meter...
That power flow that we have not much informative
Title: Re: MPG for those interested
Post by: 150234 on September 26, 2021, 12:35:29 PM
Can anway tell me why in a mk1 Jazz at 70mph in top gear I can only manage 41mph when trying to be as gently as possible?
This is the Mk 4 Jazz forum so we Mk 4 Jazz owners hope to get better mpg than your Mk 4 Jazz. In addition to the factors you have mentioned, I expect that the engine is running outside of its most efficient zone (particularly if it's 1.2 L). What's the engine rpm at 70 mph?

Getting back to the Mk 4, I got a claimed 123.9 mpg on a 6 mile trip today. However, the car was assisted by gravity - the start was about 100m higher than the end. I forgot to note the mpg for the trip in the opposite direction but it would have been somewhat lower but it highlights the effect of height difference on individual trips.
It's a 2003 mk1 with the 1.4 litre petrol. Runs at bang on 3,500 RPM at 70mph.
Title: Re: MPG for those interested
Post by: John Ratsey on September 26, 2021, 10:12:27 PM
It's a 2003 mk1 with the 1.4 litre petrol. Runs at bang on 3,500 RPM at 70mph.
I think that's the answer to your question. 3,500 rpm is well outside the zone of optimum engine efficiency. I think later Jazzes (certainly the CVT versions) are no more than 2,500 rpm at 70mph.
Title: Re: MPG for those interested
Post by: 150234 on September 26, 2021, 11:57:22 PM
This, in my opinion, is why cars shouldn't be allowed 5 gears as it just isn't enough. If the Jazz had a 6th it would be far more efficient.
Title: MPG for those interested
Post by: sportse on September 30, 2021, 12:53:00 PM
An interesting journey - I have a regular 50 mile, 70mph journey in a fairly hilly area.

Normally I get around 52mpg if itís clear and Iím mostly sitting with the ACC on.

Today I tried going at around 60mph or a bit less in ECON mode and with only very gentle acceleration.

I managed to get 61mpg, so an improvement of 9mpg.

It does show how efficient the car is to start with though, without having to drive differently at all. The heating wasnít as effective in ECON mode too.

I see the HRV gets an eco/power gauge but itís not needed in the Jazz.
Title: Re: MPG for those interested
Post by: 150234 on September 30, 2021, 03:52:31 PM
I should mention that I am currently running 10W-40 DIESEL oil in my petrol Jazz. It's thicker and is of course meant for diesel engines which also won't help fuel economy. I only realised after putting it in.
Title: Re: MPG for those interested
Post by: Roman on September 30, 2021, 05:21:01 PM
An interesting journey - I have a regular 50 mile, 70mph journey in a fairly hilly area.

Normally I get around 52mpg if itís clear and Iím mostly sitting with the ACC on.

Today I tried going at around 60mph or a bit less in ECON mode and with only very gentle acceleration.

I managed to get 61mpg, so an improvement of 9mpg.

It does show how efficient the car is to start with though, without having to drive differently at all. The heating wasnít as effective in ECON mode too.

I see the HRV gets an eco/power gauge but itís not needed in the Jazz.
Power gauge actually can help to drive more economical - you can see how much energy you use.
And using this power meter you can glide on flat road or on slope .
See technique pulse and glide, this technique works excellent on Toyota hybrids.
On Honda Jazz also work but need to sense car because we not have this power meter.
Can by added as I did but that not good to put tablet on dashboard.
Title: Re: MPG for those interested
Post by: Jazzik on October 03, 2021, 10:17:33 PM
Today a touristic trip of 257 km. (160 miles). Partly B roads (max 90 kmh / 56 mph) partly typical "touristic" roads with the same speed limit, but you hardly ever reach 70 kmh / 45 mph.
Beautiful weather, temperature visible in the pictures.

Picture 1 more or less halfway: 3.4 l/100 km. = 83.1 mpg
Picture 2 back home, more B roads: 3.6 l/100 km. = 78.5 mpg

Oh... by the way. All the trip was in B (didn't need ACC) and Econ.
Title: Re: MPG for those interested
Post by: sportse on October 06, 2021, 07:19:39 AM
Honda has now fixed the trip readings on the Honda+ app with todays update on apple - you get the correct mpg heading instead of mph.
Title: Re: MPG for those interested
Post by: Neil Ives on October 06, 2021, 09:46:51 AM
I just updated the Android version. Fuel consumption is now MPG, not MPH. I don't know if that's the only change.
Title: Re: MPG for those interested
Post by: nowster on October 06, 2021, 10:39:03 AM
Honda has now fixed the trip readings on the Honda+ app with todays update on apple - you get the correct mpg heading instead of mph.
Yes, Android is the same. However, the fuel consumed is still labelled as being in L when it's obviously in gallons.
Title: Re: MPG for those interested
Post by: sportse on October 06, 2021, 12:57:22 PM
It would also be useful to have the miles travelled in the journey log.
Title: Re: MPG for those interested
Post by: Neil Ives on October 06, 2021, 12:59:49 PM
It would also be useful to have the miles travelled in the journey log.
That might be useful.
Title: Re: MPG for those interested
Post by: Jazzik on October 06, 2021, 04:00:19 PM
However, the fuel consumed is still labelled as being in L when it's obviously in gallons.

Patience... Suzuka wasn't built in one week either... ;D
Title: Re: MPG for those interested
Post by: Kremmen on October 10, 2021, 09:12:07 AM
Just done my first topup.

Trip Computer = 64.7mpg
Actual = 63.8mpg

Near enough.

This low MPG is due to the engine kicking in and out during my first setup. My most recent trip has clocked ~73mpg
Title: Re: MPG for those interested
Post by: peteo48 on October 10, 2021, 09:59:05 AM
Even so - impressive figures. I'd settle for those. My interest is how the Mk4 responds to my short trip, urban type motoring.

Getting it tomorrow.
Title: Re: MPG for those interested
Post by: Kremmen on October 10, 2021, 10:44:03 AM
95% of my trips are motorway and fast dual carriageway A roads and I can pick my time of day.

In the 50mph roadworks section I'm averaging about 75 but the 60mph average speed section drops to about 65. Urban with a full battery is where it really scores but I haven't done any short urban journeys.
Title: Re: MPG for those interested
Post by: jamjar on October 10, 2021, 09:50:58 PM
After resetting my trip, this is what is shown as mpg. If only !!!!!
Title: Re: MPG for those interested
Post by: Kremmen on October 11, 2021, 04:03:07 AM
I've seen that before on the Civic forum where someone has filled up at the top of a hill and been able to coast downhill for far enough to trigger the displays maximum reading :)
Title: Re: MPG for those interested
Post by: nowster on October 11, 2021, 09:39:15 AM
After resetting my trip, this is what is shown as mpg. If only !!!!!
I had 199.9mpg last night on a short trip from one side of a motorway service area to another, where it had only used battery power.
Title: Re: MPG for those interested
Post by: Bazzzer on October 11, 2021, 10:57:25 AM
I actually had my Mk3 showing 199.9 mpg a couple of months ago.  That must be as high as it goes.

I'd started from a car park at approx 500' up and, after initial acceleration, trundled down to a crossroads 1.4miles away at 150'.  There was a car in front, so I couldn't have gone much faster if I'd tried.

As I approached the bottom, I saw 172.8, 187.2 and finally 199.9 mpg.
Title: Re: MPG for those interested
Post by: csp on October 11, 2021, 11:18:50 AM
On my recent trip of 290 miles, mainly dual carriageway & motorway, with 3 people and luggage on board the trip computer recorded 70mpg. The range indicator a total of out at 322 miles left in tank giving 612 miles range. Current overall mpg on trip B 64.9mpg for over 2500 miles.

I wonder how long will it be before a practical electric car will be available with a range of over 600 miles.
Title: Re: MPG for those interested
Post by: Jazzik on October 11, 2021, 11:48:35 AM
On my recent trip of 290 miles, mainly dual carriageway & motorway, with 3 people and luggage on board the trip computer recorded 70mpg.

What was the average speed during this 290 mile trip according to the BC?
Title: Re: MPG for those interested
Post by: Roman on October 15, 2021, 09:09:57 AM
Intresting
Just leave gas station after refill of 11l of RON 98 gasoline.
Trip meter 335km ODO 14721km
After leaving gas station looked on BC
This can't be true.....
Only 11l of 98 octane to 30l of 95
(https://i.ibb.co/6n8dK15/20211015-103810.jpg)
(https://i.ibb.co/gvDBMTC/20211015-103801.jpg)
Something wrong.....
Title: Re: MPG for those interested
Post by: Kremmen on October 15, 2021, 09:16:58 AM
I filled up last weekend and my tank range is currently showing 639 miles which is 1,028km so 999 may be the limit.



Title: Re: MPG for those interested
Post by: Roman on October 15, 2021, 10:17:57 AM
No Kremmen  :D
This is i km not miles - when i leave gas station there was 1030 km
Look little bit lower
Average consumption  by computer only 2.7l/100km or 141MPG itís only 18km after refill but  this newer happened before, my lowest average that I seen before is 3.3l in same driving conditions.
I newer filled 98 RON before.
Title: Re: MPG for those interested
Post by: John Ratsey on October 18, 2021, 10:29:14 PM
What was the battery charge status when you refilled and was the gas station higher than wherever you travelled to? Either of these will temporarily result in an unrepresentative estimate of the fuel consumption which is then extrapolated to the estimated miles remaining which assumes that the journey so far is representative of the total.

The attached mpg was the result of a 6 mile trip including a 90m (300ft) drop although, IIRC, the battery has near minimum at both the start and end of the trip.
Title: Re: MPG for those interested
Post by: Kremmen on October 19, 2021, 04:52:09 AM
I've seen lots of similar posts elsewhere after filling up at a high elevation fuel station.

As we run into Winter I'm not expecting the sort of figures some are achieving. I'm expecting no more than ~ 60mpg once the heater is needed. My regular weekly journey is 30 miles, mainly motorway and fast dual carriage A road with only about 1 mile urban at each end.
Title: Re: MPG for those interested
Post by: Roman on October 19, 2021, 05:04:07 PM
When I entered gas station battery has 3 bars but this can be 31-39 %, the gas station on same height that my destination.
Whatís different from my usual journeyís that engine was warmed up. Nothing more.
Now is 90 km after refill average staying on 3.1l/100km with average speed 24km/h (have short distance between runabouts and traffic lights) when possible speed kept 40km/h, something I noted is that momentarily consumption now always less than 20l/100km when engine run, actually more times kept across 12l/100km, and before mixing fuel grades game when engine run momentarily consumption rarely kept across 12l/100km, 70% of time close to 20l/100km, and when I starting to drive average consumption on trip meter B that resets every journey behaves differently- before mixing fuel always started count from 50l/100km (flat surface on parking lot) now starting counting from 25l/100km.
Maybe I see changes because our ď95 RONĒ not 95 but from 95 to 92, sometimes I hearing pinging from engine (using 95 all the time).
Honda wants minimum 95 RON for our engine.
Whe have many gas station that fails on fuel quality check of diesel and gasoline sometimes quality so bad that octane rating canít be checked .
Friend of mine refilled cheap priced 95 RON gasoline 6 months ago, when he get to home engine refused to start normal , he visited several repair shops and spend good amount of $ but nothing helped, problem gone only when all that cheap gasoline burned in engine.
Title: Re: MPG for those interested
Post by: Roman on October 22, 2021, 11:48:54 AM
Two jorneys about 14km one direction uphil(with cold engine at start) other downhill  same road (hot engine)
fuel ≥95 RON tyre pressure 2 PSI more then recommended for speed over 160 km/h (38PSI + 2 PSI front 36 PSI +2 PSI rear)  it`s not advice to do that but i can say no difference on harsh road either 35 PSI or 38 PSI or 40 PSI and visualy protector of tyre still have contact with road as with 38 PSI for front or 36 PSI for rear, but have effect on rolling resistance.
Uphill average for trip 3.0l/100km
downhill average for trip 2.7l/100km
Average for 180km after refill 3.1l/100km
Title: Re: MPG for those interested
Post by: Geoff_W on November 01, 2021, 12:19:24 PM
Two jorneys about 14km one direction uphil(with cold engine at start) other downhill  same road (hot engine)
fuel ≥95 RON tyre pressure 2 PSI more then recommended for speed over 160 km/h (38PSI + 2 PSI front 36 PSI +2 PSI rear)  it`s not advice to do that but i can say no difference on harsh road either 35 PSI or 38 PSI or 40 PSI and visualy protector of tyre still have contact with road as with 38 PSI for front or 36 PSI for rear, but have effect on rolling resistance.
Uphill average for trip 3.0l/100km
downhill average for trip 2.7l/100km
Average for 180km after refill 3.1l/100km

I've not seen that instrument display before, how do you get to it?
Title: Re: MPG for those interested
Post by: sportse on November 01, 2021, 12:50:26 PM
You'll likely get the display by plugging a dongle into the OBD port and using an app on a phone or tablet. I've seen similar displays from Prius owners.

- Can someone please confirm where the OBD port is on the Mk 4 Jazz? I know they're usually somewhere under the bottom of the dash.
Title: Re: MPG for those interested
Post by: Kremmen on November 01, 2021, 01:33:40 PM
I'm sure I spotted mine when I did the dashcam install.

From memory it's the long white port.
Title: Re: MPG for those interested
Post by: Roman on November 01, 2021, 09:23:04 PM
OBD port located on  left side under steering well slightly lower then fuse box and option power connector.
App that used on Toyota hybrid, Hyundai ioniq,  Ford hybrid and Kia Niro is Hybrid Assistant- excellent app but to my sadness not supporting Honda hybrids
When I asked author of this app if he plans to add support of Honda hybrids he answered that if Honda will be interested in this he will add support of Honda hybridsÖ..
Program that I used is Car Scanner Pro, this is diagnostic app but you can configure dashboard.
Title: Re: MPG for those interested
Post by: sportse on November 04, 2021, 04:34:34 PM
Having driven a few trips of 50 miles at motorway speeds in cold weather, Iím seeing a drop of 4mpg so far.

To be expected, hybrids tend to get maybe 5mpg less in winter.

I was surprised it was so much at high speed though, must be due to the efficiency of the system and itís use of EV mode at speed in warm weather.
Title: Re: MPG for those interested
Post by: peteo48 on November 05, 2021, 12:43:18 PM
It's been pretty cold and wet near us and I've been doing my usual stop/start short distance stuff. The fibometer was showing a tad over 60 mpg but it seems to have dropped back and settled at around 57 mpg. I reckon this might translate to 53 mpg actual which is fine by me and a 25% improvement on my Mk3.

As it happens I've just done a short trip (about 5 miles round trip but parked up for 2 hours) and I have noticed that the battery is showing full but the car is reluctant to kick into EV mode - it's clear that it won't do that whilst the climate control is on until the correct ambient temperature is reached in the cabin.

I've done about 165 miles. I have a strong urge to do a fill up to check my "real" mpg but I am trying to resist that so I can get a truer picture over a longer distance.
Title: Re: MPG for those interested
Post by: jamjar on November 05, 2021, 04:36:53 PM
I was getting an average of 62 mpg but now averaging 56mpg in the "cooler" climate.
Title: Re: MPG for those interested
Post by: aphybrid on November 10, 2021, 10:57:43 AM
First fill - early for convenience @ 382 miles gave 53.2mpg (dashboard - 52.9). Range max would be 468.

Countryside running. Mainly D last third with eco.

Looking for better as run-in completes.
Title: Re: MPG for those interested
Post by: peteo48 on November 10, 2021, 01:54:25 PM
I cracked!

Curiosity got the better of me so I topped up the tank today. 53.7 mpg and I'm pleased with that given the type of driving I've been doing. I reckon the Mk3 would have been 42 mpg at best.

Early days but the fibometer was just under 4 mpg (57.5mpg) optimistic so no change there then.

Title: MPG for those interested
Post by: sportse on November 18, 2021, 03:16:45 PM
Having been forced to drive a VW T-Cross hire car with a laggy at low speed DSG for a week, Iím finding my MPG has increased in the Jazz!

A regular country road 25 mile trip achieved 73+ mpg today - my best country mpg.
Title: Re: MPG for those interested
Post by: Kremmen on November 18, 2021, 04:13:11 PM
Mine is now hovering around the 64mpg mark. Mostly 50 and 60mph restricted motorways with the heater on.

I must say, the heater does come on fairly quick. My ICE Civic used to not push out noticeable heat till end of the local bypass, 2 miles, but the Jazz is kicking out heat half way down.
Title: Re: MPG for those interested
Post by: peteo48 on November 19, 2021, 12:54:22 PM
Mine is now hovering around the 64mpg mark. Mostly 50 and 60mph restricted motorways with the heater on.

I must say, the heater does come on fairly quick. My ICE Civic used to not push out noticeable heat till end of the local bypass, 2 miles, but the Jazz is kicking out heat half way down.

Had my first bit of proper motorway driving this Wednesday. About 40 miles - 30 motorway and 10 on A Road. Roadworks on the motorway so I rarely got anywhere near 70. At the end of this trip the Fibometer was reading just over 64 mpg and that figure includes some other short stuff with the engine on heating the cabin so pretty much in line with your experience.

I was looking at the "Which" figures for this car. They got an astonishing 91 mpg on some urban stuff but only 40 mpg on the motorway. I think these figures might be outliers - the 91 mpg seems incredible but I am sure you'd get more than 40 mpg at motorway speeds even allowing for the fact that high speed motorway work is not a hybrid's strong suit.
Title: Re: MPG for those interested
Post by: Lord Voltermore on November 19, 2021, 02:28:41 PM
I think these figures might be outliers - the 91 mpg seems incredible but I am sure you'd get more than 40 mpg at motorway speeds even allowing for the fact that high speed motorway work is not a hybrid's strong suit.
The worst I have had was about 49mpg on the A74(M) from Carlisle  climbing to Beattock summit  (IIRC they had to fit an extra railway locomotive  for this climb in the 'old days'. )  Thats with only about 500 miles from new and the ACC set for 65 mph  (where those around me may have had  70 mph showing on their speedometers.)

Maybe If I had set it for 80 mph it may have dropped to 40 mpg, but otherwise I dont know how these journalists manage get the figures they do.   Perhaps they just look at the constant fuel consumption bar which with the engine running can drop below 35 mpg at times, but balanced  up by the times you are not using any fuel at all.  Or they measure it over a very short distance pedal to the metal.

I'd say at  65 mph on  level motorway I got about  65 mpg  ,sometimes dropping to low 60's.  This may depend on tail wind or headwind.  I got roughly 1 mpg less for every 1 mph over this speed and  1 mpg more for  every mph under.  But 80 mph + would come at a fuel cost. 
 But these are very rough estimates  made over a short period.   This is about the same as my Diesel yaris under similar conditions. A few small conventional petrol cars may equal, or slightly better it on the motorway.   Its in town, and driven sensibly on rural roads where its fuel consumption is really impressive.


Title: Re: MPG for those interested
Post by: peteo48 on November 19, 2021, 05:49:15 PM
Yes - I know that climb to Beattock summit. I think your figure of 49 mpg is more realistic than the "Which" figures.
Title: Re: MPG for those interested
Post by: aphybrid on November 20, 2021, 03:33:10 AM
First fill - early for convenience @ 382 miles gave 53.2mpg (dashboard - 52.9). Range max would be 468.

Countryside running. Mainly D last third with eco.

Looking for better as run-in completes.

2nd fill - early for convenience @ 760 miles gave 51.9mpg (dashboard - 53.9). Range max would be 456.
Day previous 130 miles round trip mainly dual carriageway +/- 70mph.
Title: Re: MPG for those interested
Post by: Kremmen on November 20, 2021, 04:11:53 AM
I wonder why you're getting ~10mpg less than me ?

Can't be traffic as the engine stops.
Title: Re: MPG for those interested
Post by: Neil Ives on November 20, 2021, 09:44:23 AM
I wonder why you're getting ~10mpg less than me ?
Can't be traffic as the engine stops.
I believe it has something to do with the weight of the right foot  ::)
Title: Re: MPG for those interested
Post by: Lord Voltermore on November 20, 2021, 02:25:28 PM
I find there's a  sweet spot with the right foot, even on the motorway. Keep just within it you can  maintain speed, and still get  quite sprightly acceleration when required .  Exceed it ,even by a little, and fuel consumption can rise significantly without much extra performance.  Floor it and you become a gas guzzler.

ACC can have a heavy right foot. If the vehicle in front slows  you to say 50 mph and you then move into a clear lane the ACC will accelerate  quite  hard to regain  speed ,guzzling fuel . Better  to accelerate manually, and more gently, only letting the ACC resume control after you reach the desired speed.

Those who generally drive at 60 mph on motorways have a double mpg advantage.  Slower speed  plus they are  often protected from wind resistance by a truck in front. 

I have found mpg , and how often the car goes into EV mode, can vary  even at the same speed , same light traffic  and the same apparent gradient.   I suspect it depends on whether you have a head wind or tail wind.

Adjusting your speed by even a mph or two can keep you in the mpg sweet spot .       Unfortunately I dont find the constant mpg bar display very helpful here.  Its only shows 0 ,70 and 140 mpg.  You have to estimate the actual figure. 
It also seems the wrong way round for mpg  where a high figure is good. Better for litres/km where low is good.
Title: Re: MPG for those interested
Post by: Neil Ives on November 20, 2021, 03:14:32 PM
ACC can have a heavy right foot. If the vehicle in front slows  you to say 50 mph and you then move into a clear lane the ACC will accelerate  quite  hard to regain  speed ,guzzling fuel .
True
Title: Re: MPG for those interested
Post by: Kremmen on November 20, 2021, 03:26:10 PM
That's why I like the LIM instead on speed controlled motorways. I control the rate of acceleration.
Title: Re: MPG for those interested
Post by: Roman on November 26, 2021, 05:04:33 PM
Last tank i filled was 98 RON gasoline and computer was sure i can do 1150km to empty tank (when i use car in city) , but then i do  trip to  Dead Sea (-389m below sea level ) with speed ~90km/h from big  Tel Aviv +47m above Sea level to 477m elevation in higest point  above sea level and climate control set to+23 Celsius, with with 3 passengers  - 326km total round trip, then 216 km with one passenger on highway with speed 90km/h, and rest 432km  with one passenger in city with speed 40-50 km/h, when low fuel light up i done 955 km, car calculated consumption 3.6l/100, then consumption dropped to 3.5l/100 after another trip of 19km (in fact it should display 3.59l/100km but when car dashboard set to metric system it's less accurate then when displays UK MPG) , entered fuel station with 38km left to empty tank  i gues there left 4.7l  and i done 974km from full tank (on average with our 95 RON i can get 850km to low fuel message), this time filled 10l of 95 RON (engine  knocks  again when engine cold).
Price of gasoline in Israel - 1 UK gallon of  95 RON was 6,768 GBP and 98 RON 7,4 GBP
Title: Re: MPG for those interested
Post by: Mike Quinn on November 26, 2021, 08:35:33 PM
Iíve had the new jazz for a month now and slightly disappointed with averaging 53mpg. Thought Iíd get a bit more. Think the issue is very short distances driven 3 times a day and the batteries havenít had time to warm up therefore EV mode not kicking in. Also notice I get much better mpg when I drive over my wife with her big led foot.
Title: Re: MPG for those interested
Post by: sportse on November 26, 2021, 09:34:50 PM
Short distances in winter do drop the mpg quite a bit.

I got 40mpg for a trip recently, but on the way back it was over 50mpg.

With the engine running, if I turn off the heating it stops instantly and restarts when I switch it back on. In the summer it often doesnít need to start up if the outside temperature is warm.
Title: Re: MPG for those interested
Post by: Roman on November 26, 2021, 10:17:19 PM
Iíve had the new jazz for a month now and slightly disappointed with averaging 53mpg. Thought Iíd get a bit more. Think the issue is very short distances driven 3 times a day and the batteries havenít had time to warm up therefore EV mode not kicking in. Also notice I get much better mpg when I drive over my wife with her big led foot.
You beat my worst record....
When i have my car for 3 month i did mostly short trips 0.6-1.8 miles twice day and lightly used heater
managed to get 67 MPG but our winter is not so cold and minimal temperature last year were i live +6 Celsius.
I found that best MPG in town is when trip is not shorter then 4-5 miles and speed  up to 25mph (with this speed on level road Jazz can stay in EV mode up to 80% of time)
Check tyres pressure when they cold (low tyre pressure lowers MPG)
Usage of heater with short trips will give you worst MPG, if possible use seat heater.(now when outside temperature around +16 engine get to normal working temperature of 80 Celsius in town after traveling ~2.5 miles)
When you lightly press accelerator you can found pedal position where no acceleration or regenerative breaking occurs so when you get to you speed say 25 mph and you on level road or descending you can drive  without wasting gas or electricity some distance.
Title: Re: MPG for those interested
Post by: Mike Quinn on November 27, 2021, 10:39:49 AM
[quote author=Mike Quinn link=topic=12364.msg112170#msg112170 date=

Usage of heater with short trips will give you worst MPG, if possible use seat heater.(now when outside temperature around +16 engine get to normal working temperature of 80 Celsius in town after traveling ~2.5 miles)

Found this interesting. Went short to this morning, usually get 28 to 30mpg. Itís cold this morning 3c so didnít expect much. Turned off the heater totally and ev came in very quickly. Got 54mpg. Is this The answer I wonder. Certainly worth trying a few times to see.

However not sure Is it the heater the issue or the ac? 
Title: Re: MPG for those interested
Post by: Roman on November 27, 2021, 11:32:23 AM
[quote author=Mike Quinn link=topic=12364.msg112170#msg112170 date=

Usage of heater with short trips will give you worst MPG, if possible use seat heater.(now when outside temperature around +16 engine get to normal working temperature of 80 Celsius in town after traveling ~2.5 miles)

Found this interesting. Went short to this morning, usually get 28 to 30mpg. Itís cold this morning 3c so didnít expect much. Turned off the heater totally and ev came in very quickly. Got 54mpg. Is this The answer I wonder. Certainly worth trying a few times to see.

However not sure Is it the heater the issue or the ac?
Heater turns on when you choose on climate control temperature higher then outside/in vehicle temperature, more difference between outside or in vehicle temperature and temperature you set more energy will be consumed.
Heater also starts in summer if temperature that set becomes higher then outside or in vehicle.
Title: Re: MPG for those interested
Post by: Mike Quinn on November 27, 2021, 12:32:21 PM

However not sure Is it the heater the issue or the ac?
[/quote]
Heater turns on when you choose on climate control temperature higher then outside/in vehicle temperature, more difference between outside or in vehicle temperature and temperature you set more energy will be consumed.
Heater also starts in summer if temperature that set becomes higher then outside or in vehicle.
[/quote]

Yes but is the issue the heater or the air con.  As You can turn the heater on but have the aircon off
Title: Re: MPG for those interested
Post by: Lord Voltermore on November 27, 2021, 03:49:16 PM


Yes but is the issue the heater or the air con.  As You can turn the heater on but have the aircon off

If you have climate control set to  Auto  the heater will be used if it needs to raise cabin temperature to the set temperature ,air con used if it needs to reduce it. .   The right hand knob increases or reduces heater fan speed which may indirectly  affect the amount of heat extracted from the engine and fuel used to maintain engine temperature and battery power for the fan.
If the need is to raise cabin temperature the air con is usually off.

If you press the button for rapid windscreen clearance BOTH heating and air con are used.  (air con dehumidifies)

If you just want air con without automatically maintaining a set temperature the aircon button will switch this on and auto climate control off.

A 'normal 'car has an engine driven air conditioning compressor ,,a direct loading that increases fuel consumption.
  But I think the  Mk4 uses an electrically driven compressor (so it can still run in ev mode) .The engine may need to run more often to provide it with battery power but the effect on fuel consumption is reduced.

A heavy right foot can have a big affect on fuel consumption. You dont have to drive like a lunatic to fall foul of this.
The secret is to  keep within the sweet spot.  Its possible to accelerate quite rapidly without any conscious use of the throttle.    A bit like following slight curves without consciously steering  .  It needs very delicate and subtle  use of the throttle. If a driver has difficulty with this it may help to use Econ mode which suppresses throttle response.  (and climate control) . You can always give it some extra 'welly' when required.
Title: Re: MPG for those interested
Post by: peteo48 on November 27, 2021, 05:41:24 PM
I think the advice about throttle control is very important. The old adage that you should imagine an egg between your foot and the throttle has a lot of merit. I like to gently squeeze rather than push hard if that makes sense.

An additional benefit, if you have the conventional CVT box in Mk2 and Mk3 models is it makes the "rubber band" effect far less pronounced.
Title: Re: MPG for those interested
Post by: Roman on November 27, 2021, 06:10:48 PM
Throttle control may be more effective if we can see how much power we taking from battery, I not understand Honda, they include power meter on insight, clarity, new CR-V e:HEV, HR-V e:HEV, but Jazz e:HEV not, there plenty space on screen, they can put it as simple linear meter above real time ICE consumption or replace it with power meter, this can help to get better mileage.
Of course I can use OBD tool with car scanner to add  this function but not everyone can do that and this is not good, as this requires to have another smartphone or tablet and need to be mounted on dashboard.
When I used this app with elm327 adapter I have set on screen power meter and I clearly see how much energy used, and also simple to found accelerator pedal position when I want to glide after I get to speed I wanted, need to play with accelerator pedal to get power consumption close to 0 (possible to do that also without car scanner but much difficult)
In this case when consumption at 0 on meter car gradually loses speed if we on level road like with manual transmission in neutral , or accelerate when we on slope  but this more efficient then accelerating and then braking by using electric braking as we loses some energy.
Title: Re: MPG for those interested
Post by: Roman on November 27, 2021, 06:41:42 PM
 :D
Looked now spritmonitor
And compared fuel consumption on my page and on pages of other owners of new Honda Jazz with similar average consumption.
Interesting Ö.
Consumption starting to decrease after 5-6 months of drivingÖÖ
Is this time needed to understand how to drive more efficiently or something else ?
Title: Re: MPG for those interested
Post by: Kremmen on November 28, 2021, 01:51:20 AM
My old 1.8 auto Civic used to fluctuate between 45mpg/50mpg winter/summer, virtually no town driving.

My Jazz is doing around 64mpg/70mpg winter/summer, same conditions.

I'm happy and I certainly wouldn't be driving round with the heating off and wearing a big fluffy coat and gloves just to get a few more mpg
Title: Re: MPG for those interested
Post by: Mike Quinn on November 28, 2021, 11:11:17 AM
My old 1.8 auto Civic used to fluctuate between 45mpg/50mpg winter/summer, virtually no town driving.

My Jazz is doing around 64mpg/70mpg winter/summer, same conditions.

I'm happy and I certainly wouldn't be driving round with the heating off and wearing a big fluffy coat jhat and gloves ust to get a few more mpg

I agree to a certain extent. If my mpg was in the same ballpark as others I wouldnít be too bothered about it but when I see there is a clear difference between my 53mpg and your 64 in all conditions itíll drive me nuts until I found out why.

So of course the obvious, why put the heater on at all when driving from cold as itís only going to blow cold air. Unless you need to de-mist. So 2c this morning and left heater Off and again went into ev pretty much straight away. So as I do a few short journeys a day this could be whatís dragging the mpg down. Iíll persevere with this theory and see how our goes.
Title: Re: MPG for those interested
Post by: Lord Voltermore on November 28, 2021, 12:56:59 PM
All cars have a significantly increased fuel consumption  with short journeys from a cold start.  Some  just dont display mpg figures  as obviously as the Mk4  if at all. 

I know it doesnt help to mention a function you dont have but  I'm wondering how much not having heated seats and steering wheel affects your figures .

So far ,with temperatures down to about 3c  I have  found the heated seats and wheel heat  up quickly and give sufficient heat for the early part of the journey. After a few miles the engine is warm enough to take over heating duty without too much affect on economy. This coincides with the seats getting a little too toasty and needing turning down or off. 

But admittedly I have not yet needed to use the screen demist/defrost function.

I still think heated seats (and wheel) are luxuries I could do without if necessary   ,  but its nice to have them.


Title: Re: MPG for those interested
Post by: culzean on November 28, 2021, 01:01:56 PM
All cars have a significantly increased fuel consumption  with short journeys from a cold start.  Some  just dont display mpg figures  as obviously as the Mk4  if at all. 

I know it doesnt help to mention a function you dont have but  I'm wondering how much not having heated seats and steering wheel affects your figures .

So far ,with temperatures down to about 3c  I have  found the heated seats and wheel heat  up quickly and give sufficient heat for the early part of the journey. After a few miles the engine is warm enough to take over heating duty without too much affect on economy. This coincides with the seats getting a little too toasty and needing turning down or off. 

But admittedly I have not yet needed to use the screen demist/defrost function.

I still think heated seats (and wheel) are luxuries I could do without if necessary   ,  but its nice to have them.

IIRC Jocko stopped using the heater after startup and watched his scangauge for engine temperature to rise before turning heater on ( or maybe watched the blue light ).
Title: Re: MPG for those interested
Post by: peteo48 on November 28, 2021, 01:13:19 PM
All cars have a significantly increased fuel consumption  with short journeys from a cold start.  Some  just dont display mpg figures  as obviously as the Mk4  if at all. 

I know it doesnt help to mention a function you dont have but  I'm wondering how much not having heated seats and steering wheel affects your figures .

So far ,with temperatures down to about 3c  I have  found the heated seats and wheel heat  up quickly and give sufficient heat for the early part of the journey. After a few miles the engine is warm enough to take over heating duty without too much affect on economy. This coincides with the seats getting a little too toasty and needing turning down or off. 

But admittedly I have not yet needed to use the screen demist/defrost function.

I still think heated seats (and wheel) are luxuries I could do without if necessary   ,  but its nice to have them.

I know EV drivers who have heated seats see them as a major ally in increasing range in really cold weather in that they don't draw as much power as the car's main heating system (usually a heat pump).

I tend to have the Climate Control set at 21 degrees and on auto so, in my case, use of heated seats would be another additional drain on the battery. I guess I could reduce the thermostat by a few degrees, use the heated seats and get extra efficiency that way.

But I can't be bothered. I am delighted with the fuel consumption. If the car can get north of 50 mpg with my diet of short stop/start journeys in towns I am well pleased.
Title: Re: MPG for those interested
Post by: Kremmen on November 28, 2021, 01:37:07 PM
As I've posted before, I'm very pleased with the heater.

My old Civic used to take about 2 miles down my local 50mph by-pass before it started puffing any warmth. The Jazz starts blowing warm air in half that distance.

I've got climate set to auto 21.5C
Title: Re: MPG for those interested
Post by: Roman on November 29, 2021, 04:48:01 AM
Comfort or better MPG
Choose of everyone, we living in different climates, donít forget that, in my country rarely temperature reach lower then +5 ( if I not in Ramon crater)
And of course I use heater when I need it, but only when my journey relatively long but again we not have temperature such as -15, with true cold winter nothing to do with MPG heater should be used, but  21 degrees C in freezing winter wil eat too much gasoline, I may heat salon up to 16 degrees C (just because this temperature comfortably fo me) and first 2-3 minutes of drive if defrost not needed only heated seat.
Title: Re: MPG for those interested
Post by: Kremmen on November 29, 2021, 07:21:23 AM
I wonder if it does ?

Initially, to get the water hot, yes, but once it's hot, would the normal engine run to charge the HV battery be alm9st enough to keep the water hot.

At the moment it's -2c out there in London so the heater, if only to keep the inside windows clear is probably needed.

**** the MPG hit :D
Title: Re: MPG for those interested
Post by: Derek cranage on December 05, 2021, 10:18:25 PM
Out of interest my last car was a Merc B200 automatic ( DSG type of gear box). At just below 60,000 miles it had averaged 49.8 mpg from new and this did include some caravan towing. I often had 62 or 63 mpg on a run and my wife, she drives it softer than me, had achieved over 70 mpg
These are actual figures based on fuel purchased, not what the car said. I am not a hard driver and as it was a second car it was mainly run on longer journeys with very little town work.  all my cars are garaged and I do think this helps in winter. The car had climate control and I had it set at 20C and I cannot ever remember switching it off,including the AC  I just never touched it winter or summer.
I just hope the Crosstar I have on order will be better for the atmosphere
I do think the jazz would be a lot better in town work than the Merc but on run not much difference
Title: Re: MPG for those interested
Post by: peteo48 on December 06, 2021, 10:40:15 AM
Excellent mpg figures Derek - was the Merc a diesel? I'm finding the Mk4 Jazz is the first car to equal the mpg I got from my 2005 Mk5 VW Golf 1.9TDI.
Title: Re: MPG for those interested
Post by: Lord Voltermore on December 06, 2021, 11:10:00 AM
Out of interest my last car was a Merc B200 automatic ( DSG type of gear box). At just below 60,000 miles it had averaged 49.8 mpg from new and this did include some caravan towing.
If you still intend towing a caravan, or any trailer, bear in mind this is illegal  with a  Jazz Mk4 and Crosstar. They have no maximum tow weight type approval recorded on their registration document.
Title: MPG for those interested
Post by: sportse on December 22, 2021, 01:03:32 PM
The first trip of the day with a cold soaked car has quite an difference on the mpg for that trip.

It was minus 4 last night, minus 1 when I started the car and defrosted - I got my lowest mpg so far of 45.4 today for a 70mph trip with the heater required as outside it was mostly freezing.

Itís still quite good mpg though.

(https://uploads.tapatalk-cdn.com/20211222/ab975a3482247330e33bfe2111158dcb.jpg)
Title: Re: MPG for those interested
Post by: Hicardo on December 26, 2021, 06:56:28 PM
Quite a drop in winter over summer mpg figs, which is to be expected of course.  I was getting 64mpg average, now thats down to about 56mpg average.  tied into that are more shorter trips, so perhaps its exaggerated a little.  still , I think thats still super economical.   8) 8)
Title: Re: MPG for those interested
Post by: Kremmen on December 27, 2021, 04:14:05 AM
Similar, I'm down from ~66 to 60 on average.

As posted, the need for heating, warming the engine from freezing and lights is to blame I guess.

Title: Re: MPG for those interested
Post by: peteo48 on December 27, 2021, 01:15:47 PM
I seem to be stuck on about 52 mpg at present - allowing for the optimism of the on board computer I guess I'm on around 47/48 mpg. Just looking back at my previous car - a Mk3 - I'd be in mid to late 30s at this time of year. My first tank indicated 54 mpg (actual) and this was October/November.

I think, as a ball park figure, over a year, my average might pan out at about 52 mpg - almost exactly 10 mpg better than my Mk3. My stop/start short stuff, predominantly in urban areas would challenge the fuel economy of any ICE car.

In reality I use very little fuel anyway given my annual mileage of less than 3,000 so the cost savings whilst nice are not a big deal.
Title: Re: MPG for those interested
Post by: Kremmen on December 27, 2021, 01:32:08 PM
I keep wondering whether a tank full of E5 would make any difference
Title: Re: MPG for those interested
Post by: peteo48 on December 27, 2021, 01:40:35 PM
I've wondered about using E5 - my small mileage would make the cost difference insignificant. My unscientific brain wonders whether, given the engine is used mostly as a generator so, presumably not even close to be being under significant load, it would improve anything?
Title: Re: MPG for those interested
Post by: Kremmen on December 27, 2021, 02:22:13 PM
Low mileage here as well.

Picked mine up 3rd Sep and I'm nearly on 800 miles.

When I think back to the 70's when I was doing 30k a year as a part time minicab in West London..
Title: Re: MPG for those interested
Post by: sportse on December 27, 2021, 04:19:41 PM
I've wondered about using E5 - my small mileage would make the cost difference insignificant. My unscientific brain wonders whether, given the engine is used mostly as a generator so, presumably not even close to be being under significant load, it would improve anything?
It will be a bit cleaner inside as E5 usually contains a higher concentration of cleaner additives.

When the generator is called on for full power, E10 might be a few percent lower than the power with E5. I believe the performance figures are taken using the best pump fuel available.

At high speed cruise the engine is actually connected to the wheels via a fixed clutch , so the small normal engineimprovements from E5 should be seen then.
Title: Re: MPG for those interested
Post by: Jazzik on December 27, 2021, 05:36:00 PM
(https://www.cheesebuerger.de/images/midi/konfus/c050.gif)
It will be a bit cleaner inside as E5 usually contains a higher concentration of cleaner additives.

Who told you that fairy tale...?
Title: Re: MPG for those interested
Post by: sportse on December 27, 2021, 05:58:36 PM
(https://www.cheesebuerger.de/images/midi/konfus/c050.gif)
It will be a bit cleaner inside as E5 usually contains a higher concentration of cleaner additives.

Who told you that fairy tale...?
https://www.shell.co.uk/motorist/v-power-fuels.html

If it wasnít true likely the advertising standards agency would stop them.
Title: Re: MPG for those interested
Post by: Jazzik on December 27, 2021, 06:09:20 PM

https://www.shell.co.uk/motorist/v-power-fuels.html
........................................................................................(https://www.cheesebuerger.de/images/midi/froehlich/a048.gif)
If it wasnít true likely the advertising standards agency would stop them.

(https://www.cheesebuerger.de/images/midi/froehlich/a055.gif)

Title: Re: MPG for those interested
Post by: sportse on December 27, 2021, 06:33:26 PM

https://www.shell.co.uk/motorist/v-power-fuels.html
........................................................................................(https://www.cheesebuerger.de/images/midi/froehlich/a048.gif)
If it wasnít true likely the advertising standards agency would stop them.

(https://www.cheesebuerger.de/images/midi/froehlich/a055.gif)

On every car I've owned, I can tell the difference in torque/HP between standard fuels and super - it will be increased further now with E5 and E10.

On the Toyota Auris and Yaris hybrids I used to own, running on the super unleaded also made a big difference to vibration both when the ICE was starting up and also at max power on slip roads.

MPG increase on super pays for some of the difference in cost - I'm very happy to pay the remaining difference for the increased performance and smoother running.

I only intend to run the Jazz up to a maximum of 90k miles to stay in warranty, so very long term engine health increases on super (150/200k miles) won't benefit me.

To anyone who hasn't tried Shell V-Power/etc - try a tank and see if your full tank mpg/etc is improved.

On older cars I've bought, around 50/60k miles, the first tank of premium has made the car run worse as it has been cleaning out the engine.
Title: Re: MPG for those interested
Post by: Jazzik on December 27, 2021, 07:55:07 PM
(https://www.cheesebuerger.de/images/midi/verschiedene/k026.gif)

Made a trip of 106 km (65 mi) today in typical winter conditions. The car was started at 11:30 am in the garage, where the thermometer showed +2įC. It was -7įC outside at that time. The destination was 53 kilometers. We arrived at 12.25 pm. It was about 12 km. (8 mi) city traffic and 41 km. (25 mi) local roads with a speed limit of 90 kmh (56 mph).
We were at our destination for more than 2Ĺ hours, the car parked at -6įC.
Returned the same way after a (very) cold start, arriving home around 4 pm, temperature -7įC.
Sun all day and little wind. Heating the entire trip at 21.5įC, econ and in "B". Fuel: Euro 95, here in Poland (still) E5.
According to the BC average speed 45 kmh (28 mph), fuel consumption 4.3 l/100 km. (65.7mpg).
Let that BC "lie" just 0.2 liters, then it is a real consumption of 4.5 l/100 km. (62.8mph)!
I think this is "ice cold" an excellent consumption!
Title: Re: MPG for those interested
Post by: Jazzik on December 27, 2021, 09:03:21 PM
On every car I've owned, I can tell the difference in torque/HP between standard fuels and super - it will be increased further now with E5 and E10.

On the Toyota Auris and Yaris hybrids I used to own, running on the super unleaded also made a big difference to vibration both when the ICE was starting up and also at max power on slip roads.

Our previous car was a Toyota Yaris Hybrid. Here in Poland we always used E95 E5. But (pre-covid) we drove thousands and thousands of miles in Germany, the Netherlands, Belgium and France. Always on E10....
I have never seen, heard or felt any difference. No vibrations when starting the ICE and maximum power on slip roads was fine. As it was on E5.
Maybe there could be a difference in mpg, but there was also (much) difference in conditions.

Conclusion: I am an insensitive person or others are hypersensitive.

Theoretically, a car engine would have a few percent higher consumption on E10 than on E5. But do you know that a difference in headwind or tailwind of 1 or 2 Beaufort makes a much bigger difference? And do you drive with an anemometer on your roof?
Title: MPG for those interested
Post by: sportse on December 28, 2021, 06:50:20 AM
On every car I've owned, I can tell the difference in torque/HP between standard fuels and super - it will be increased further now with E5 and E10.

On the Toyota Auris and Yaris hybrids I used to own, running on the super unleaded also made a big difference to vibration both when the ICE was starting up and also at max power on slip roads.

Our previous car was a Toyota Yaris Hybrid. Here in Poland we always used E95 E5. But (pre-covid) we drove thousands and thousands of miles in Germany, the Netherlands, Belgium and France. Always on E10....
I have never seen, heard or felt any difference. No vibrations when starting the ICE and maximum power on slip roads was fine. As it was on E5.
Maybe there could be a difference in mpg, but there was also (much) difference in conditions.

Conclusion: I am an insensitive person or others are hypersensitive.

Theoretically, a car engine would have a few percent higher consumption on E10 than on E5. But do you know that a difference in headwind or tailwind of 1 or 2 Beaufort makes a much bigger difference? And do you drive with an anemometer on your roof?
Perhaps Iím sensitive to performance- I used to turn off the air conditioning on my civic on slip roads as it made a difference to acceleration.

My Yaris hybrid had a slight shudder when the ICE started up and a slight rattle under full power with ordinary 95 unleaded.

My long term average mpg on the Yaris hybrid was 57mpg on the gauge, which was a real tank average of 55mpg. But the Yaris was much slower than the Jazz at higher speeds.

Auris hybrid mpg was quite a bit lower, in winter I might see 42mpg average.

Jazz is doing well, faster than Auris and gets still over 50mpg mostly - only dropping to 45mpg when very cold.
Title: Re: MPG for those interested
Post by: culzean on December 28, 2021, 10:31:45 AM

Perhaps Iím sensitive to performance- I used to turn off the air conditioning on my civic on slip roads as it made a difference to acceleration.


Normally the aircon clutch gets disconnected by ECU when a sudden press of accelerator is detected.  The clutch also gets disengaged when starting the engine...
Title: Re: MPG for those interested
Post by: Jazzik on December 28, 2021, 12:15:22 PM
My Yaris hybrid had a slight shudder when the ICE started up and a slight rattle under full power with ordinary 95 unleaded.

My long term average mpg on the Yaris hybrid was 57mpg on the gauge, which was a real tank average of 55mpg. But the Yaris was much slower than the Jazz at higher speeds.

Jazz is doing well, faster than Auris and gets still over 50mpg mostly - only dropping to 45mpg when very cold.

Our Yaris didn't have a shudder nor a rattle with ordinary 95 E5 or 95 E10.
The long term average mpg on the Yaris hybrid, measured over 4 years https://www.spritmonitor.de/en/detail/842930.html was 57,89 mpg (4,88 l/100 km).

Our Jazz is (till now) doing slightly better: from August till now 63,48 mpg (4,45 l/100 km).

Title: Re: MPG for those interested
Post by: nowster on December 29, 2021, 11:56:41 PM
On every car I've owned, I can tell the difference in torque/HP between standard fuels and super - it will be increased further now with E5 and E10.

That might not hold true for the Mk4 Jazz due to its running the petrol engine in its power band.
Title: Re: MPG for those interested
Post by: sportse on December 30, 2021, 06:07:57 AM
On every car I've owned, I can tell the difference in torque/HP between standard fuels and super - it will be increased further now with E5 and E10.

That might not hold true for the Mk4 Jazz due to its running the petrol engine in its power band.
It should have an effect, but likely less than on a Toyota hybrid.

When cruising at high speed the petrol engine in the Jazz will be directly connected to the wheels, so any improvements in engine performance for torque/HP should be direct to the wheels.

When working solely as a generator, on super fuel, it will be giving maximum HP in generating.

Someone ran tests on a dyno with different fuels on a family car and found 3-4 HP increase with super fuel.
Title: Re: MPG for those interested
Post by: Jazzik on December 30, 2021, 05:07:28 PM
A fuel is a mixture of different hydrocarbons (including octane and heptane) that are present in different dosages. The ratio expressed in % between the content of octane and heptane is called the octane number.

According to the European directive, gasoline SP98 has an octane number of 98 and is composed of 98% octane and 2% heptane; gasoline SP95 has an octane number of 95 and is composed of 95% octane and 5% heptane.

And as for the engine?

The ratio of octane to heptane has an impact on the engine's auto-ignition mechanism. In practice, SP98 ignites at a higher temperature and pressure than SP95. This distinction is a result of how the different hydrocarbons respond to pressure. For example, octane will ignite less quickly than heptane. The lower the octane number, the greater the risk of spontaneous combustion at the time of compression in the engine cylinders.

Which petrol for which car?

Initially, it is recommended to use the fuel recommended by your car manufacturer. Anyone who thinks that a higher octane number leads to better performance is wrong.

If your engine is equipped to run on SP95 gasoline, like most regular cars, there's no point in filling up SP98. Certainly not in our Jazz with an ICE that runs with Atkinson cycle... You will pay more without getting more in return.

The proper functioning of your car depends on the compression level of your engine. This has an impact when the contact of the petrol with the air produces a spark. This explosion takes place at the right time with the right fuel, sensor checked.

And now that "damned" E10.

What is E10 petrol and bioethanol?
E10 fuel consists of a minimum of 90% petrol and a maximum of 10% bioethanol (so it can also be 94.5% petrol and 5.5% ethanol...). If the percentage of ethanol is below 5%, the gasoline is sold under the name E5. Ethanol, another word for alcohol, is often added to gasoline to reduce reliance on fossil fuels. Because the production and composition of E10 petrol is less bad for the environment, it is referred to as a sustainable petrol.

In principle, with a full tank of E10 fuel you will get a little less far than with a tank of regular E5 petrol. This is because E10 has a slightly lower energy density. A petrol engine consumes a maximum of about two percent more when E10 is refueled.

Two percent... Here in Poland we don't have E10 (yet), so we use E5. Our Jazz has so far a measured average consumption of 4.55 l/100 km = 63.5 mpg. So theoretically, consumption on E10 would have been 63.5 - 2% = 62.2 mpg.
Overtaking two, three, maybe four times quickly, a hundred miles more highway, more often headwind, less tailwind, etcetera etcetera probably gives more difference in consumption...

Oh... and maybe the air will also stay about 2% cleaner with E10...(https://www.cheesebuerger.de/images/midi/froehlich/a048.gif)
Title: Re: MPG for those interested
Post by: sportse on December 30, 2021, 05:56:01 PM
IIRC manufacturers all use the highest octane fuel available for their official fuel economy and performance figures - any tiny improvement is worth it to beat competitors.

I think they also tape up wing mirrors/etc just to get a tiny improvement. Another reason why we don't have spare wheels anymore, anything they can do to get a tiny increase in MPG/reduction in emissions.
Title: Re: MPG for those interested
Post by: Kremmen on December 30, 2021, 06:01:48 PM
Some manufacturers played with the software to detect when it was being tested to falsify emissions and possibly MPG figures.

They'll try anything.

Vertical windscreen wipers to reduce drag.
Title: Re: MPG for those interested
Post by: nowster on December 30, 2021, 06:20:18 PM
When cruising at high speed the petrol engine in the Jazz will be directly connected to the wheels, so any improvements in engine performance for torque/HP should be direct to the wheels.

Actually, it's only directly linked when it's in overdrive. If you floor it, the little gear will disappear from the display.
Title: Re: MPG for those interested
Post by: peteo48 on December 31, 2021, 01:36:21 PM
With the recent spell of milder weather I am noticing EV mode kicking in much more largely because less power is needed to heat up the car. Heating the cabin will be my main drag on decent fuel consumption during winter months.
Title: Re: MPG for those interested
Post by: Roman on December 31, 2021, 07:00:50 PM
When we run our car in town actualy no difference or small difference in  MPG when 98 RON used (said effects only more advanced timing with 98 RON in summer)
1 month ago I did trip with elevation from sea level to +477m fully loaded when used 98 RON and seen with car scanner that when motor generator have enough load car computer retarded ignition down to+7 degree (on flat road timing somewere on +35 degree) on that tank i did 974km from 35l of 98 RON gasoline - 2 trips 163km with speed 90km/h fully loaded with A/C set to 22 C with elevation to +477m then down -420m to Dead Sea and back  same route , rest is trips with 1 passenger - 2 trips 110km each with speed 90km/h and rest 448km  short trips 10-15km each in town (in town computer showed consumption 3.0l/100km average for 448 km ).
Now i switched back to 95 RON - in winter 98 RON not shows better MPG.
When outside temperature is low the 95 RON less prone to detonation.
But yes right fuel does better MPG
Should i get bad 95 RON gasoline that in reality in best case 89-90 RON i will get bad fuel economy, but if that real 95 RON it will be OK because our car should use 95 RON minimum.
Take look https://www.spritmonitor.de/en/detail/1195531.html (https://www.spritmonitor.de/en/detail/1195531.html) this driver from Switherland uses 95 RON and getting excellent MPG.
Title: Re: MPG for those interested
Post by: sportse on January 12, 2022, 12:05:12 PM
After running my Jazz exclusively on Shell V Power 99RON for 7,000 miles I decided to try ordinary Shell 95RON E10 and switched over several fills agoÖ

On the motorway the drop in mpg has only been around 1mpg, whereas the cost is 10% more for the V Power.

There is a difference in performance though, not so much in total power but in the way it is delivered- V Power seems to have more pull at motorway speeds. Itís only the initial pull, actual performance seems similar.

Whereas ordinary 95 has more pull at lower speeds so is much better around town - there is less of an initial delay when pulling away/accelerating.

Ordinary 95 seems to actually be a better fuel for the Jazz, it appears to rev lower when under light/medium acceleration.

If I was driving around town a lot, Iíd predict that 95 would actually get better mpg than 99!
Title: Re: MPG for those interested
Post by: Kremmen on January 12, 2022, 12:23:29 PM
I was considering topping up with Tesco 'premium' next time but based on your test I'll stick with the 95RON E10 jollop.
Title: Re: MPG for those interested
Post by: peteo48 on January 12, 2022, 02:10:11 PM
Thinking along similar lines. I need to refuel so rarely that the extra cost per litre is not a deal breaker but if there is literally no point I'll probably stick with E10.
Title: Re: MPG for those interested
Post by: sportse on January 12, 2022, 02:50:55 PM
Thinking along similar lines. I need to refuel so rarely that the extra cost per litre is not a deal breaker but if there is literally no point I'll probably stick with E10.

It surprised me, in other cars I've owned there were benefits of using the super fuel - with the Jazz just being a generator engine usually it doesn't seem to make any real difference.

If anything, I'd say the Jazz runs slightly smoother on 95 instead of super. In my previous Yaris hybrid it was the other way round, but that had a gearbox and the petrol engine was driving the wheels through it in combination with the electric motors.
Title: Re: MPG for those interested
Post by: Expatman on January 12, 2022, 03:08:08 PM
I wonder in the longer term if the extra cleaning agents in Shell super petrol would benefit the engine? Also won't filling with E10 with 10%  hydroscopic ethanol increase the rate of water absorption into the fuel and is that likely to have long term corrosion risks for fuel lines etc?
Title: Re: MPG for those interested
Post by: Kremmen on January 12, 2022, 03:10:46 PM
I did a similar exercise in my first 8G Civic. I used Tesco Standard, BP Ultimate and Shell V Power. At that time I was doing a tank full a fortnight so I ran each for a month to reduce any hybrid mixes.

The results were almost identical with an average of only 1mpg difference and no noticeable performance gain.
Title: Re: MPG for those interested
Post by: sportse on January 12, 2022, 09:26:03 PM
I wonder in the longer term if the extra cleaning agents in Shell super petrol would benefit the engine? Also won't filling with E10 with 10%  hydroscopic ethanol increase the rate of water absorption into the fuel and is that likely to have long term corrosion risks for fuel lines etc?
Most fuels have cleaning agents added, itís just that the super fuels have more.

The standard agents should be fine, as for E10 as itís marked on a sticker in my fuel flap as approved Iím not worried - I tend to get through a tank or so every week so water absorption shouldnít be an issue.

If the car was being left for a few months it might make a difference, but you could fill up with super fuel before leaving the car. V power is marked as Ďup toí E5 but may actually be E0.
Title: Re: MPG for those interested
Post by: peteo48 on January 13, 2022, 03:39:56 PM
Just filled up. 299 miles and 3 bars left on the fuel gauge. 48.8 mpg for the last tank.

It doesn't look great but it's about 10 mpg better than my MK3 would have been in similar conditions. Average speed 15 mph which tells you all you need to know about what sort of driving I've been doing.

The effect on mpg of cold weather is quite stark. At least 5 mpg spent on keeping the heater on I reckon as a ball park figure.
Title: Re: MPG for those interested
Post by: peteo48 on January 22, 2022, 10:43:40 AM
Just on mpg and referring to the latest "Which" review which had the Jazz as the best car in the small car category, it seems the Jazz averages better than the small car average which is 48.7 mpg. "Which" got 55.4 mpg average and this is from all driving scenarios.

Only the Yaris did better.

Keeping warm in the winter is the biggie but, even in this colder period and allowing for my short trip driving profile, I achieved just under 49 mpg.

Can't wait for the warmer weather!
Title: Re: MPG for those interested
Post by: Kremmen on January 22, 2022, 11:05:15 AM
So that's Which? and Whatcar that have the Jazz top of the small car sector.

 :D
Title: Re: MPG for those interested
Post by: Roman on January 22, 2022, 10:42:59 PM

Only the Yaris did better.

Keeping warm in the winter is the biggie but, even in this colder period and allowing for my short trip driving profile, I achieved just under 49 mpg.

Can't wait for the warmer weather!

Yes keeping warm Ö.
I remember from time I leaving in Ukraine in winter most drivers put in front of radiator cardboard or special designed ďmaskĒ for radiator grill
Interesting do Yaris have active grille shutters ?
I canít understand, some Honda models do have them, but Jazz that can be super fuel efficient Honda decided not use them.
Some time ago I get excellent fuel economy (2.6-2,8l/100km) but I think that time is 98 RON fuel, but that something else
When I topped up fuel I did 16km trip before that, and engine was warmed to itís working temperature.
I suspect that when carís  tested for fuel consumption engine already at itís working temperature.
That how in Japanese national test for fuel efficiency they get 2,8l/100l, when engine warmed up I can easily get 3l/100km in town, in current weather (+12) on road with  speed restriction 80km/h I getting 3,2l/100km on long 100km trips.
Title: Re: MPG for those interested
Post by: Kremmen on January 23, 2022, 05:11:32 AM
The front of the MK4 has a lot less open grill which is probably why it warms up quicker.
Title: Re: MPG for those interested
Post by: Bristol_Crosstar on January 23, 2022, 08:30:41 AM
I tend to use the heated seats initially and only switch on the climate system once the engine has had a chance to warm up. I've been getting around 60mpg in winter and I was getting 70mpg in summer but I don't do much motorway driving, I have the ECO button on all the time.
Title: Re: MPG for those interested
Post by: Roman on January 23, 2022, 10:41:02 AM
The front of the MK4 has a lot less open grill which is probably why it warms up quicker.

But still loses coolant temperature in town, if you driving at speeds 40-50km/h with temperature outside that far from winter temperature in UK. Seen temperature loses when outside +10, and because of that to get best fuel economy displayed need to drive twice more distance then in summer
Title: Re: MPG for those interested
Post by: Kremmen on January 23, 2022, 11:37:49 AM
I've no idea about coolant temp as it hasn't got a gauge.

One would have been useful.
Title: Re: MPG for those interested
Post by: PTJAZZ on January 23, 2022, 03:41:57 PM
Today 7000 Km.

According to BC average 3.3 L, real 3.56 L

Not bad for the best Hybrid on the market.
Title: Re: MPG for those interested
Post by: Jazzik on January 23, 2022, 05:57:44 PM
Great average consumption! (https://www.cheesebuerger.de/images/smilie/froehlich/a020.gif)
On Spritmonitor https://www.spritmonitor.de/de/detailansicht/1259542.html I see that you travel 33% on motorways, 33% on country roads and 33% in the city.
My questions:
- Where and under what climate conditions do you live?
- At what speed do you drive on the motorway?

Title: Re: MPG for those interested
Post by: Jazzik on January 23, 2022, 06:12:43 PM
Double post... :-[
Title: Re: MPG for those interested
Post by: Roman on January 23, 2022, 07:17:32 PM
I've no idea about coolant temp as it hasn't got a gauge.

One would have been useful.
I using car scanner app with elm327 adapter.
Title: Re: MPG for those interested
Post by: PTJAZZ on January 24, 2022, 01:45:37 PM
Jazzik I live in Lisbon and my average speed on motorway is maximum 100 Km / h
Title: Re: MPG for those interested
Post by: Jazzik on January 24, 2022, 03:29:26 PM
Ah... that explains it! Average max. daytime temperature around 14, 15įC instead of maximum around or just above 0įC (and regularly significantly lower) here in Toruń makes a difference!
Our average speed on the motorway (where the maximum allowed speed is 140 km/h) is normally around 120 km/h and sometimes a bit faster...
Title: Re: MPG for those interested
Post by: nigelr on January 24, 2022, 10:52:35 PM
The hybrid scores in several ways, one being that kinetic energy is converted to electricity and  recuperated (stored) in the battery while braking or decelerating, and the stored electricity can be converted back to kinetic energy to propel the car. A non-hybrid  simply wastes kinetic energy to heat in the brake pads and discs . Other differences are adoption of the Atkinson cycle for the engine, which trades off torque for economy of  fuel consumption, Atkinson cycle engines are better when assisted by a hybrid electric motor to plug the gap for reduced engine torque
Also the hybrid system means that the engine (when running) spends more time in its most efficient range. Something I noticed when I first got my Crosstar and used Torque + a Bluetooth OBDII reader to monitor the engine behaviour was that the engine was never run at below 1600 rpm. My presumption is that excess power goes to the battery which then takes over and lets the engine go to sleep. This behaviour is very noticeable in crawling traffic. The hybrid system, however, provides minimal benefit during motorway cruising.

Really useful information, John, thanks. I'm considering upgrading my beloved Mk2 ahead of retiring next year -- it's a fabulous car, but the manual 5 speed box is a bit of a pain on my arthritic feet, and it's a wee bit noisy on the motorway. I'm also fascinated by the hybrid technology.

Thanks again.

Title: Re: MPG for those interested
Post by: Roman on January 28, 2022, 09:47:56 AM
I found another culprits  for poor fuel economy - rain and wet asphalt - on roads with speed limit 55 mph at speed 55 mph when asphalt wet and in rain i can only get 70 MPG, when there is no rain and asphalt is dry i can squize 80-85 MPG (on long trip of course)
I not remember that with gasoline car i had so big difference in fuel consumption in similar conditions.
But also  70MPG for me big difference - with my previus cars in town i can`t ahive more then 28MPG (Yaris 4 gear automatic 2001), 47MPG (Baleno 2018 5 manual gear ) 22 MPG (Vitara 2019 1.0l turbo 6 gear auto )
Title: Re: MPG for those interested
Post by: sportse on February 05, 2022, 11:02:47 AM
I've found the MPG gauge in my EX to be almost spot on. Perhaps the 16" wheels help the calculations

The gauge was showing 50.3 mpg for a whole tank vs 50.5 calculated from the miles and litres added.
Title: Re: MPG for those interested
Post by: Kremmen on February 05, 2022, 11:14:04 AM
Mine has been a couple of MPG out as has all my Civics.

There must be a driving style or road condition/traffic congestion that gets it right whilst others are more difficult to compute.
Title: Re: MPG for those interested
Post by: sportse on February 05, 2022, 12:21:39 PM
My driving must be 90+ % motorway, so it's likely easier for it to work out on long trips.

The Honda app records the mpg ok, but the fuel used figure varies a lot.
Title: Re: MPG for those interested
Post by: peteo48 on February 05, 2022, 01:08:32 PM
Mine has been a couple of MPG out as has all my Civics.

There must be a driving style or road condition/traffic congestion that gets it right whilst others are more difficult to compute.

I think that must be right. With most cars I have owned the car's computer has been reliably about 4 mpg optimistic. I try to drive in as smooth a way as possible but there is no getting away from the fact that I am braking, stopping, accelerating almost constantly with the type of trip I do.
Title: Re: MPG for those interested
Post by: Mouse on February 05, 2022, 02:48:52 PM
First refuelling 465 miles, 30.65 litres so 69.3 mpg (car claimed 73 mpg).

Second refuelling 515 miles, 32.90 litres so 71.2 mpg (car claimed 75.1 mpg).

The "fibometer" appears to be about 5% optimistic - nothing new there!

I would try a different Garage. Our local garage was overcharging by 10% on their metering and were finally caught by Trading Standards.
Title: Re: MPG for those interested
Post by: Roman on February 05, 2022, 03:39:11 PM
Mine has been a couple of MPG out as has all my Civics.

There must be a driving style or road condition/traffic congestion that gets it right whilst others are more difficult to compute.

I think that must be right. With most cars I have owned the car's computer has been reliably about 4 mpg optimistic. I try to drive in as smooth a way as possible but there is no getting away from the fact that I am braking, stopping, accelerating almost constantly with the type of trip I do.

Give more space between you and car ahead to allow more time for braking or stop on traffic lights if that possible (not too much cars on road) start gentle deceleration if you see ahead red traffic light,  try to coast when that possible  -  use energy flow animation to understand when car starting regenerative braking, when you see green energy flow to battery slightly press gas pedal and monitor your speed - if you speed decreasing slowly on level road you coasting and almost not using energy, if you on downhill you will see fast acceleration but again you will not use energy
Jazz become super efficient when engine coolant warmed up to 70-80 Degrees C
In summer enough to drive maybe 5km to get engine warmed up, in winter this taking more time - in my case with +12 degrees C I need to drive 11km or more to get engine warmed up.

https://listers.co.uk/news/2014/07/10-ways-to-increase-your-hybrids-fuel

Title: Re: MPG for those interested
Post by: Neil Ives on February 05, 2022, 07:45:13 PM
My current driving style is to try to minimise use of the brake. Seeing a stop light ahead I take my foot off the pedal and try to reach the light as it changes. If I'm not using ACC I set the gear-lever to B.
Title: Re: MPG for those interested
Post by: Kremmen on February 06, 2022, 05:24:03 AM
Same here, my 1980's IAM tutor taught me a lot. Plus, my double deck PSV training included smoothness and planning ahead. You don't want to hit the brakes with standing passengers.
Title: Re: MPG for those interested
Post by: peteo48 on February 06, 2022, 10:49:37 AM
My current driving style is to try to minimise use of the brake. Seeing a stop light ahead I take my foot off the pedal and try to reach the light as it changes. If I'm not using ACC I set the gear-lever to B.

Yes - I try to do that. I'm also in Econ and B most of the time. I reckon I'm on about 49 mpg with this current tank. To be fair I'd be on late 30s in my Mk3 at this time of year with an overall mpg of just over 42 mpg. A huge chunk of my mpg must be the engine being on to keep me warm and the fact that I rarely reach optimum operating temperature.

I'm quite happy with this - I reckon the Mk4 will end up about 25% more efficient than my Mk3.
Title: Re: MPG for those interested
Post by: cee on February 06, 2022, 03:47:33 PM
Hi All,
Greetings to you All!
First post so please be gentle.
I have 2021 Jazz and something is off the the MPG and real consumption. According to the on board computer my car is doing around 57-59 MPG but at the same time I am only getting max 380 miles from the full tank. How is this possible? with that MPG i should be getting over 500miles from the tank. Did only 5 full tanks from new but 380 miles from full tank is consistent. Is something wrong or I am missing something? What are you guys getting from full tank?
Btw, this is my 4th Honda and second Jazz and I am very happy with the car just mildly concerned.
Title: Re: MPG for those interested
Post by: Kremmen on February 06, 2022, 03:50:31 PM
Have you calculated actual fuel put in v actual mileage covered to double check?
Title: Re: MPG for those interested
Post by: sportse on February 06, 2022, 03:54:21 PM
380 miles per tank is all I get, but my average is around 50mpg.

There is some fuel left when the range reads zero, maybe up to a gallon but I always refill before 100 miles range is left as the last 100 miles drops quicker than it should do.
Title: Re: MPG for those interested
Post by: cee on February 06, 2022, 04:11:14 PM
HI,
yes i did, 37 liters in vs 380 miles that is less than 43 MPG. confusing...
Title: Re: MPG for those interested
Post by: Lord Voltermore on February 06, 2022, 04:25:02 PM
HI,
yes i did, 37 liters in vs 380 miles that is less than 43 MPG. confusing...

What conversion factor are you using?   37 litres is 8.13 gallons,    which over 380 miles is 46.7 mpg.   
Title: Re: MPG for those interested
Post by: Kremmen on February 06, 2022, 04:41:23 PM
That still doesn't compute v the onboard calculator.

Last time I heard of such a discrepancy was a son siphoning a few gallons out when dad wasn't looking.
Title: Re: MPG for those interested
Post by: Jazzik on February 06, 2022, 06:18:05 PM
I am (more than) a little surprised when I read above that cee drives 380 miles on a full tank. ⛽
Is that the same Honda Jazz e:HEV as mine?
I see significant differences in fuel consumption. Some here seem to have a significantly higher consumption than I do, others rather comparable.
So far I have an average (measured) consumption of 62.9 MPG.
I drive normally, not like a nearsighted grandpa but also not like Max V., always in Econ and B mode (except on the highway with ACC). Heating and air conditioning are used as needed.

I've never refueled after less than 386 mi (that was 5.72 Imp.gal), but I normally do between about 420 and 490 miles on a tank of fuel.
The last fill-up was in mid-January (Winter in Poland!) after 435 miles traveled, a fill-up of 7.15 gallons (60.8 MPG).
In the fall, I filled up 6.90 gallons on Oct. 8, after 487.8 miles: 70,7 MPG (80% local roads with a max speed of 90 km/h = 56 mph and 20% city traffic).

Why do I see here such (rather significant) differences?
Title: Re: MPG for those interested
Post by: Roman on February 06, 2022, 06:29:04 PM
6.25l/100km is too much, how that can be done ?
Maybe short trips with climate control set to 25 degrees C ?
Or even worse case short trips with climate control set to 25 degrees C  on highway with fast acceleration and hard braking afterwards.
Title: MPG for those interested
Post by: sportse on February 06, 2022, 08:16:50 PM
Cruising at 70mph/110kph Iíve found I get 50mpg, it doesnít matter if I accelerate slowly or  donít brake/use B/ use eco mode - I still get almost the same 50mpg.

However as soon as I drop below 50mph Iím getting nearer 70mpg. Either roadworks on the motorway or country roads.

Thereís not much the hybrid system can do to save mpg for hours of 70mph constant cruising unfortunately.

Itís the same with pure EV cars - as soon as you add high speed cruising into a journey your range drops massively.

Some good information on real world EV motorway ranges in this review - itís the same for the Jazz and other hybrids.

Title: Re: MPG for those interested
Post by: peteo48 on February 06, 2022, 08:28:01 PM
Yes - I've said this before but if you look at Mk4s on spritmonitor there is a huge range of mpg figures. The way I see it is that it is possible to achieve superb mpg figures but this almost certainly requires a particular driving profile. On a warm day, doing a decent mileage on a mixture of town roads with some country roads in the mix it will be possible to top 60 mpg - maybe even better.

This can lead to disappointment so the more relevant metric for me is what my previous (non hybrid) car did. I am disappointed that I can't join the 60 mpg club but I'm bumping along at just over 50 mpg at a time of year where my Mk3 would have been doing late 30s/early 40s at best.
Title: Re: MPG for those interested
Post by: cee on February 06, 2022, 10:42:06 PM
Hi Guys, i do understand differences in MPG we are all getting but what baffles  me is the discrepancy between MPG on the trip computer vs miles per tank. Can you let us know how many miles are getting from the full tank please?


Sent from my iPad using Tapatalk
Title: Re: MPG for those interested
Post by: Jazzik on February 06, 2022, 11:15:31 PM
what baffles  me is the discrepancy between MPG on the trip computer vs miles per tank.

I keep track of my consumption on Spritmonitor https://www.spritmonitor.de/en/ , where you note the actual amount of litres/gallons fueled and the number of kilometers/miles driven.
In addition, you can also fill in what the on-board computer indicated as consumption (plus additional information that you want to add yourself).
I have kept track of that and the conclusion is that my actual consumption so far is about 4.5% higher than what my on-board computer indicated.
Title: Re: MPG for those interested
Post by: Kremmen on February 07, 2022, 05:23:03 AM
Those figures are so adrift I'd be getting the dealer to check for any fuel leaks.
Title: Re: MPG for those interested
Post by: sportse on February 07, 2022, 06:15:27 AM
Hi Guys, i do understand differences in MPG we are all getting but what baffles  me is the discrepancy between MPG on the trip computer vs miles per tank. Can you let us know how many miles are getting from the full tank please?


Sent from my iPad using Tapatalk
Itís a 40 litre tank I believe, at 50mpg if you ran it completely empty theoretically it would give a 440 mile range vs the 380 miles the range meter says.

Most cars have a reserve of fuel when the range says zero, so that works out at around a gallon or so.
Title: Re: MPG for those interested
Post by: Lord Voltermore on February 07, 2022, 08:05:58 AM
Hi Guys, i do understand differences in MPG we are all getting but what baffles  me is the discrepancy between MPG on the trip computer vs miles per tank. Can you let us know how many miles are getting from the full tank please?

Sorry, I missed your main concern. I think you accept its possible to get less than 50 mpg in unfavourable conditions such as high motorway speeds,short journeys etc  . ( My car has averaged about 65 mpg over 2000 miles, but even so there are times when the constant fuel consumption bar is in the low 30's.mpg. Get this too often average consumption plummets )

But the discrepancy in on board computer figures does seem excessive.   Maybe the calibration is wrong. I'd think  a physical fuel  leak, or mechanical problem increasing fuel consumption is less likely. Wouldnt you smell fuel or notice poor running? 

Not sure exactly how it works, but I'd have thought part of the system would measure actual fuel flow to the engine.  If this increases,for whatever reason,it should still  register as fewer mpg.
But I may be wrong.  The system may only estimate fuel consumption based on engine running time, throttle settings, load ,temperature etc.
Either way its probably a good idea to have it checked by a dealer.

Title: Re: MPG for those interested
Post by: culzean on February 07, 2022, 09:39:51 AM

Not sure exactly how it works, but I'd have thought part of the system would measure actual fuel flow to the engine.  If this increases,for whatever reason,it should still  register as fewer mpg.
But I may be wrong.  The system may only estimate fuel consumption based on engine running time, throttle settings, load ,temperature etc.
Either way its probably a good idea to have it checked by a dealer.

Normally the ECU keeps track of the injector 'on time' - which is the amount of fuel squirted into engine,  if the fuel pressure is constant then the amount of time the injector valve is open can give the volume of fuel used.
Title: Re: MPG for those interested
Post by: sportse on February 07, 2022, 09:43:44 AM
When I picked up my car from new with only 8 miles on it and itís first full tank of fuel, the fuel range remaining was over 600 miles!

Iíve never seen anything like that again, not sure how the computer managed to get a figure so high with so few miles.
Title: Re: MPG for those interested
Post by: Kremmen on February 07, 2022, 10:30:44 AM
Mine still shows just north of 600 each fill up.
Title: Re: MPG for those interested
Post by: John Ratsey on February 07, 2022, 10:50:21 AM
When I picked up my car from new with only 8 miles on it and itís first full tank of fuel, the fuel range remaining was over 600 miles!

Iíve never seen anything like that again, not sure how the computer managed to get a figure so high with so few miles.
The engine was already warm when the car returned from getting the tank filled and it might have been a slightly downhill journey as well.

I keep a record of the car's claimed mpg as well as what I calculate from fuel into the tank. The car is averaging about 4.5% high.

As already noted, cold weather and short trips are an mpg killer. I always have trip mpg showing on the big screen and this highlights how the mpg improves from a low start. I keep the heating off until the engine is warmed up which means several miles (that's probably why Honda gave us heated seats).
Title: Re: MPG for those interested
Post by: Kremmen on February 07, 2022, 11:37:21 AM
My actual, miles covered v squirt put in is calculated via Spritmonitor, under my avatar.

Currently 61.3 but I reckon that will increase at it warms up, depending on AC power.
Title: Re: MPG for those interested
Post by: Lord Voltermore on February 07, 2022, 12:22:00 PM
I once filled up at Sainsburies then drove a few hundred metres to park.  IIRC it showed 117 mpg !
Title: Re: MPG for those interested
Post by: sportse on February 08, 2022, 04:23:12 PM
I recently drove a 30 mile trip - 60% urban, 20% at 50mph and 20% at 70mph - total average was 68mpg.

Itís high steady speed that really drops the mpg in the Jazz. (But 50mpg is still very good - my old Accord 2.0 petrol would be doing maybe mid thirties mpg)
Title: Re: MPG for those interested
Post by: peteo48 on February 11, 2022, 05:36:52 PM
Just a little comment on mpg. I think my car is doing around 48 to 49 miles per gallon as things stand. I've been doing some digging in spritmonitor and there is a decent sized cohort who are getting well under 50 mpg over longish periods. I saw one owner who even had the odd tank under 40 mpg. The lowest mpg, for a tank, was 36 mpg.

We are still in the winter but I can't see me ever getting close to 60 mpg, even on a run.

What am I doing wrong? I drive like a granny on sedatives. Don't get me wrong, the mpg is significantly better than the Mk3 but 60 mpg? How?
Title: MPG for those interested
Post by: sportse on February 11, 2022, 06:51:04 PM
Just a little comment on mpg. I think my car is doing around 48 to 49 miles per gallon as things stand. I've been doing some digging in spritmonitor and there is a decent sized cohort who are getting well under 50 mpg over longish periods. I saw one owner who even had the odd tank under 40 mpg. The lowest mpg, for a tank, was 36 mpg.

We are still in the winter but I can't see me ever getting close to 60 mpg, even on a run.

What am I doing wrong? I drive like a granny on sedatives. Don't get me wrong, the mpg is significantly better than the Mk3 but 60 mpg? How?
It seems to be a combination of time,speed and temperature.

If I stay under 50mph on journeys I can easily get 60+mpg.

Journeys need to be sufficient distance/time - say 20+ miles.

The first start of the day after being parked outside is always lower in the cold/freezing weather. The second trip gets better mpg as the engine/cabin are already warm.

I donít baby the accelerator- something I learned from Prius. Car engines are most efficient under 80% load, so accelerating briskly up to the speed limit and then maintaining the speed maybe the car will use EV mode quite a bit once cruising.

FYI hybrid cars work backwards to ordinary ones - they get worse mpg on a run, and better mpg when stuck in slow moving traffic.
Title: Re: MPG for those interested
Post by: Kremmen on February 12, 2022, 05:27:26 AM
I got 60mpg yesterday, 8C outside, on a mainly motorway run from Heathrow to Reading  :)

Title: Re: MPG for those interested
Post by: sportse on February 12, 2022, 06:00:49 AM
I got 60mpg yesterday, 8C outside, on a mainly motorway run from Heathrow to Reading  :)
Was that all at 70mph? Thereís nothing I can do to get above 50mpg at 70mph on 50+ mile trips in the Jazz :(

Itís 10% lower mpg than my mark 1 Yaris hybrid got on long motorway trips.

As soon as the speed drops, the mpg goes up though.
Title: Re: MPG for those interested
Post by: Kremmen on February 12, 2022, 07:35:02 AM
Not 70 as I tend to max out around 60, I find it more relaxing. Plus M4 junctions 3 to 8/9 are still 50mph in the roadworks.
Title: Re: MPG for those interested
Post by: Roman on February 12, 2022, 08:08:21 AM
There he get 58 MPG
Cold weather lots of highways and hills, and he not baby gas pedal to.
Title: Re: MPG for those interested
Post by: Bristol_Crosstar on February 12, 2022, 08:29:33 AM
Just a little comment on mpg. I think my car is doing around 48 to 49 miles per gallon as things stand. I've been doing some digging in spritmonitor and there is a decent sized cohort who are getting well under 50 mpg over longish periods. I saw one owner who even had the odd tank under 40 mpg. The lowest mpg, for a tank, was 36 mpg.

We are still in the winter but I can't see me ever getting close to 60 mpg, even on a run.

What am I doing wrong? I drive like a granny on sedatives. Don't get me wrong, the mpg is significantly better than the Mk3 but 60 mpg? How?
Do you have ECO switched on, I find it does make a difference of up to 10%?
Title: Re: MPG for those interested
Post by: Kremmen on February 12, 2022, 08:44:08 AM
Just for info my Eco is off.
Title: MPG for those interested
Post by: sportse on February 12, 2022, 09:30:50 AM
It seems to be long distance high speed where the mpg drops - set the cruise control for a real 70mph (72mph indicated on 16Ē wheels) and you only get 50mpg :(

The hybrid system canít really help in those situations as itís limited in what it can do.

The petrol engine is directly connected to the wheels during high speed cruising.
Title: Re: MPG for those interested
Post by: Roman on February 12, 2022, 12:05:22 PM
The petrol engine is directly connected to the wheels during high speed cruising.

Because at this speeds using ICE directly connected to transmission more eficient.
Title: Re: MPG for those interested
Post by: sportse on February 12, 2022, 12:19:33 PM
The petrol engine is directly connected to the wheels during high speed cruising.

Because at this speeds using ICE directly connected to transpission more eficient.
50mpg seems to be as efficient as it gets for the 1.5 petrol engine at 70mph.

Its still maybe 20% better than the mark 2 Jazz loan cars I used to have.
Title: Re: MPG for those interested
Post by: peteo48 on February 12, 2022, 12:31:49 PM
Thanks to Roman for posting the You Tube video from the Irish car dealer. I'd settle for 58 mpg given the type of driving on that trip - it's excellent and he doesn't hold back, you can hear the petrol engine being pushed hard at times.

I have ECON on and use B mode nearly all the time.

I've decided to do a 50 mile or so "mixed" run when I next fill up. I see 60 mpg as a target - I just want to see it :)
Title: MPG for those interested
Post by: sportse on February 12, 2022, 01:43:19 PM
The best Iíve had was through long 50mph sections of motorway- just set the cruise control and I was getting 75mpg.

It shows how wind resistance plays a big difference in fuel economy:

75 mpg at 50mph

50mpg at 70mph

Many of the so called real ranges on pure EV cars are based on speeds around 50mph - in the real world if you are on the motorway long distance at 70mph it will be considerably less. Combined with cold weather and itís even worse.
Title: Re: MPG for those interested
Post by: Roman on February 12, 2022, 03:15:02 PM
ACC only after you get to desired speed !!!
If ACC will be used in stop and go trafic it can increase fuel consumption !
Title: Re: MPG for those interested
Post by: sportse on February 12, 2022, 03:29:18 PM
ACC only after you get to desired speed !!!
If ACC will be used in stop and go trafic it can increase fuel consumption !

I never use ACC if there is traffic anywhere near, too many scares from the system getting confused. I used it only once in stop and go traffic and it tried to kill me! It brakes too late, and then accelerates too hard. In traffic that is speeding up and slowing down the system can't cope at all.

It's only used on an empty road with no cars in range - if I'm approaching another vehicle I'll switch it off before the car can see it.
Title: Re: MPG for those interested
Post by: peteo48 on February 12, 2022, 03:34:15 PM
Yes - I will use it very sparingly. Emptyish stretch of Motorway or Dual Carriageway on a long trip just to give the right leg a bit of a rest.
Title: Re: MPG for those interested
Post by: Kenneve on February 12, 2022, 03:43:40 PM
Current total mileage today, since April 21 =  7336 miles, Fuel consumption over that distance = 65.9MPG
Driving style: Mostly 'B' mode except where ACC is required, (which is not often).  ECO = Off

I have to confess that only about 12-15% of those miles are motorway miles and then generally circa 65Mph.
Most motoring is urban/country roads where speed limits are 50mph or less.

These figures are from the dashboard readouts, not really concerned about any errors in quoted/real results, since all my previous Jazz cars have used the same basis for consumption comparison.
Typically, they were usually in the mid 50s Mpg, so more than happy with the MK4 improvements.
Title: Re: MPG for those interested
Post by: Hub on February 12, 2022, 06:07:25 PM
My mileage now 7615 with mpg of 60.7 measured by "tank full" method and an excel spreadsheet. A mixture of long and short journeys,  mostly on A roads - B mode in towns and Eco mode for 80% of the time.
Very happy with the Jazz, comfortable,  quiet and  economical!
Title: Re: MPG for those interested
Post by: Lord Voltermore on February 13, 2022, 07:56:56 AM
I have averaged about 65 mpg in mixed use over 2000 miles. 

   On motorways  I tend to set the ACC to 65mph.  This gives mpg  of upper 50's to low 60's  (Although i havnt done enough miles to fully analyse it as slight hills up or down, wind direction etc are factors. )
 And the speedo is quite accurate so it really is 65 mph.  At this speed many cars speedos will be reading  70 mph so I am actually keeping pace with a lot of the other cars  and with a slight edge over trucks. 

Of course I have my moments over 70 mph,(I thought it was a work trip officer, not social. Oh you have photos)  and consumption does suffer .   
Title: Re: MPG for those interested
Post by: Kremmen on February 13, 2022, 08:41:26 AM
I got 60mpg yesterday, 8C outside, on a mainly motorway run from Heathrow to Reading  :)

..... and 73.6MPG coming back this morning :

(https://i.imgur.com/83GyPmJ.jpg)
Title: Re: MPG for those interested
Post by: sportse on February 14, 2022, 02:37:10 PM
I've noticed that the seat heaters seem to be programmed to tie in with engine heating.

The engine was off and the seat heaters on, when I switched the heaters off the engine started straightaway to give heat.

I then switched the seat heaters back on and the engine switched off instantly.

Probably only makes a tiny difference to mpg in cold weather but an interesting quirk.
Title: Re: MPG for those interested
Post by: Kremmen on February 14, 2022, 03:01:48 PM
I've never used the seat or steering wheel heaters.

At least we get warm cloth instead of cold leather.

In summer we get cool cloth instead of hot leather.
Title: Re: MPG for those interested
Post by: Sandysally on February 14, 2022, 09:29:55 PM
I have had the Jazz EX Style for 3 weeks and so far am disappointed that despite deliberately driving very frugally to try an achieve best fuel consumption, I have achieved an average of 54mpg over 500 miles. I have followed all available guidance including switching off AC and switching on Economy mode.  I have driven a couple of journeys of 200 miles on an A road at speeds of 50 to 60 and the rest in town at speeds on average of 30. I have been extremely light on the accelerator and have found so far that I achieve best fuel consumption at low speed, in town.  I really am so very disappointed that the car has achieved nothing like the 62 mpg claimed to be normal and nowhere in the region of the 70mpg that all reviewers claim is fairly achievable.  My Mk 11 Jazz regularly achieved 50mpg and sometimes even 60. I am hopeful that the disappointing mpg is down to the cold weather but any advice would be appreciated.  My gripe apart, the car is amazing to drive and beautifully finished
Title: Re: MPG for those interested
Post by: Kremmen on February 15, 2022, 04:45:36 AM
I'm regularly getting average 60 to 70 mpg. My journeys are mostly 50mph restricted motorways with urban roads at each end.

One thing to watch, if you can, is the 'instant mpg' readout on one of the display options. What I'm noticing is that on the motorway at a steady speed the instant mpg will change from max 140mpg to around 35/40 mpg as the engine cuts in and out to keep the battery charged.

What I have noticed is that where the mororway is slightly uphill the engine will kick in but once at the crest and you start the downhill slope, albeit a very slight gradient, it's reading the max 140 almost all the downhill section.

When I leave the motorway and drive on fairly clear 30 to 50 urban roads my average mpg does start to drop.
Title: Re: MPG for those interested
Post by: sportse on February 15, 2022, 07:11:03 AM
In normal weather hybrids tend to get 5-10mpg more.

In the winter the car has to burn petrol to provide heat for the cabin, as well as keeping the emissions system up to temperature.

Over 10,000+ miles my long term average is around 50mpg. I only see maybe 2mpg more in the summer as most of my driving is motorway at 70mph.

Iíve stopped paying much attention to mpg now, with my driving I get 50mpg which is fine for the combination of performance and refinement.

Itís 10% less than my Yaris hybrid did, but much better motorway performance.

The difference in fuel costs with higher mpg isnít that much above 50mpg.
Title: Re: MPG for those interested
Post by: Kremmen on February 15, 2022, 07:27:49 AM
10,000 miles...... I've only just gone over 1,000

I used to get 50mpg average in my auto Civic so I'm looking forward to warmer weather. Then we'll be moaning about aircon MPG :)
Title: Re: MPG for those interested
Post by: Lord Voltermore on February 15, 2022, 09:42:10 AM
On transcontinental  journeys you sometimes follow key routes for hours. I often see the same distinctive cars that hack past me at a high rate of knots,  pass me again 2 hours later. And after a very brief stop for fuel or the loo I pass the same lumbering truck i passed 2 hours earlier. 

  A  life in the fast lane  buys you surprisingly little extra time in the course of a day. Enough time to fit an expensive coffee into your frantic schedule maybe. 
Fewer fuel stops = more time. Although sometimes I   need a comfort stop without refueling. What a waste.

Driving fast can be fun.   But  these days I am happy to drop a few mph  to save a few quid and a few polar bears. 
 
 
Title: Re: MPG for those interested
Post by: Kremmen on February 15, 2022, 10:47:54 AM
I remember travelling at the legal 50mph along the various roads from Oxford to Worcester. I had an impatient *** behind who couldn't get past on the twisty roads.

Just before Evesham is a short section of dual carriageway. Past he shot.

He turned left and shot down the Evesham bypass whilst I went through Evesham itself (knowing the road and it was early and quiet).

A few miles down the road there he was again in my mirrors and he knew it was me again :D

The bypass may be faster but it's quite a bit longer.
Title: Re: MPG for those interested
Post by: sportse on February 15, 2022, 11:37:55 AM
On my long motorway journeys I often see people shoot past me and disappear into the distance, only to catch them up many miles later in congestion.

Certainly in the south itís pointless having a high performance car.

If you are in Germany with their no speed limit roads it makes a difference, however Teslas/etc doing 150mph only get 100 miles of range I believe, so in a race across Germany a jazz may actually beat them?

To a normal driver the difference between 50mpg and 60mpg might only be 30p a day according to one online calculator I used - not much on a £23k car.
Title: Re: MPG for those interested
Post by: sportse on February 15, 2022, 11:52:37 AM
10,000 miles...... I've only just gone over 1,000

I used to get 50mpg average in my auto Civic so I'm looking forward to warmer weather. Then we'll be moaning about aircon MPG :)
Iím on track to complete maybe 11-12k miles in under 6 months!

A bit more than my usual 15k pa miles but Iíve been on a few UK holidays.
Title: Re: MPG for those interested
Post by: Lord Voltermore on February 15, 2022, 03:37:11 PM
I have had the Jazz EX Style for 3 weeks and so far am disappointed that despite deliberately driving very frugally to try an achieve best fuel consumption, I have achieved an average of 54mpg over 500 miles. I have followed all available guidance including switching off AC and switching on Economy mode.  I have driven a couple of journeys of 200 miles on an A road at speeds of 50 to 60 and the rest in town at speeds on average of 30. I have been extremely light on the accelerator and have found so far that I achieve best fuel consumption at low speed, in town.  I really am so very disappointed that the car has achieved nothing like the 62 mpg claimed to be normal and nowhere in the region of the 70mpg that all reviewers claim is fairly achievable.  My Mk 11 Jazz regularly achieved 50mpg and sometimes even 60. I am hopeful that the disappointing mpg is down to the cold weather but any advice would be appreciated.  My gripe apart, the car is amazing to drive and beautifully finished
I havnt driven much on long A road journeys since the winter,Its currently mostly half hour runs in the the suburbs. My average  over 2000miles since october is about 63 mpg, without being super frugal.  I never use Eco mode . But   I  am surprised you are not getting 60mpg + on  long A road runs . even in winter.
I dont mean any offence  but maybe your idea of  extremely light on the throttle has still not yet  quite hit the sweet spot of throttle control  that  gives best results in a mk4.  It  really is ' foot on an eggshell'  stuff.  You almost get the car to go faster by mind  control, not by consciously pressing on the pedal as you might in a mk 11.   Hit the sweet spot and the car performs very respectably  under 'mind control ' -more than enough for normal driving  .  Exceed it by even a little  (which will be necessary sometimes when hill climbing and brisk overtakes ) and fuel consumption suffers.     Eco mode helps by suppressing throttle response, but its still possible to over do it. If you can master throttle control without using ECO mode the car feels much more perky and responsive.

I can only suggest persevering with gentle throttle control. It falls in nicely with the instant torque response in EV mode. And again ,sorry if you already have.    Also,  it can make a significant difference  if you are travelling uphill ,or downhill on average during the journey. Even if its not enough that you would normally  notice.  Maybe you were just unlucky with the terrain on your trips so far.
Title: Re: MPG for those interested
Post by: peteo48 on February 15, 2022, 04:40:01 PM
I have had the Jazz EX Style for 3 weeks and so far am disappointed that despite deliberately driving very frugally to try an achieve best fuel consumption, I have achieved an average of 54mpg over 500 miles. I have followed all available guidance including switching off AC and switching on Economy mode.  I have driven a couple of journeys of 200 miles on an A road at speeds of 50 to 60 and the rest in town at speeds on average of 30. I have been extremely light on the accelerator and have found so far that I achieve best fuel consumption at low speed, in town.  I really am so very disappointed that the car has achieved nothing like the 62 mpg claimed to be normal and nowhere in the region of the 70mpg that all reviewers claim is fairly achievable.  My Mk 11 Jazz regularly achieved 50mpg and sometimes even 60. I am hopeful that the disappointing mpg is down to the cold weather but any advice would be appreciated.  My gripe apart, the car is amazing to drive and beautifully finished

I can see where you are coming from. I'm just starting to get slightly annoyed at the fuel consumption. I got my car in mid October and I'm showing a genuine 50.8 mpg over, admittedly, a relatively short total mileage of 650 (ish) miles. On the car's computer I'm showing 52 mpg at the moment which, from past experience, is probably 4 mpg out so 48 mpg on this current tank.

This is better than my Mk3 in similar conditions but probably about 8 mpg at best better. I drive in B mode with the ECON button on most of the time.

It's a matter of psychology. You, like me, are seeing road tests showing mid 50s or better, other owners getting over 60 mpg.

One thing I did do to see if my (relatively) poor mpg was exceptional was to check similar cars on the fuel consumption website - spritmonitor.de. On that site there are plenty of drivers grubbing along at 50 mpg and significantly lower in some cases. Digging deeper I've seen a driver who has covered a lot of miles in an EX and he is averaging a tad over 50 and, on some tanks, he was down in the mid to late 30s.

I do a lot of short stuff, allegedly the car's forte in terms of mpg, but not in my case. I put it down to the fact that, in this cold weather, the engine is on a lot of the time both charging the battery AND keeping the cabin warm.

I think, though, we need to wait for the better weather. If I'm still grubbing along at 48 to 50 mpg I will be very disappointed.

Poor fuel economy, or perhaps more accurately, disappointing fuel economy aside - I do love the car.
Title: Re: MPG for those interested
Post by: Kremmen on February 15, 2022, 04:47:38 PM
If you do a lot of short journeys from cold then that'll do it.

Almost all my journeys are ~30 miles so lots of warm miles, engine, tyres, etc. From what I've read, anything under 16 miles and the cars not fully warm.
Title: Re: MPG for those interested
Post by: peteo48 on February 15, 2022, 05:07:04 PM
I think the Which test - as opposed to WLTP - arrived at a figure of 56 mpg overall. Just looking again at Sandysally's post above, she is on about 54 mpg having had the car 3 weeks - 3 very cold weeks. I think she might be pushing 60 mpg when the weather improves.

I'd definitely settle for 56 mpg overall. Warmer weather and a few longer trips should help. I guess, given the hybrid, I see 50 mpg as the minimum - a psychological thing.
Title: Re: MPG for those interested
Post by: sportse on February 15, 2022, 05:35:26 PM
I've done some rereading of the Jazz brochure - I'd missed that under normal WLTP the official MPG is 62 average but if you look further at the motorway only figure (WLTP high) it's only 48mpg.

Which is near what I'm getting, so quite accurate.

The Jazz Mk4 does do 0-60 in around 9 seconds, compared to competitors such as new Yaris that are doing it in 11 seconds, so the lower performance is probably why they are getting maybe 10% better fuel economy.

Compared to the Mk3 Jazz auto, the Mk4 is quicker to 60mph and also accelerating in gear. The fact it gets better mpg while being significantly faster is quite good.

Duel: Honda Jazz III 1.3i-VTEC CVT vs Honda Jazz IV Crosstar e:HEV (https://zeperfs.com/en/duel7616-8682.htm)
Title: Re: MPG for those interested
Post by: Jazzik on February 15, 2022, 05:45:32 PM
For those who use the Jazz (or any car for that matter) a lot for short trips, try following this fuel-saving tip: Combine as many of those short trips as possible. So don't go for example to the dentist in the morning (1st cold start), shopping after lunch (next cold start) and than, at the end of the afternoon also quickly to the bank (3rd cold start) and so on...
If you combine these three in this example, the first ride gives quite a high consumption, but after half an hour at the dentist the engine has not really cooled down and the second ride the consumption already looks better and the engine gets really warm. After 20 to 30 minutes in the supermarket you start with a reasonably warm engine and you have an even better consumption.

I know: a rather obvious tip, but you have to put in some effort...
Title: Re: MPG for those interested
Post by: peteo48 on February 15, 2022, 05:54:38 PM
Yes - I have been trying to collate trips into one. It's the weather I think. In October I filled the car after around 170 miles just to get an inkling of what the mpg was like and the first tank showed over 54 mpg (it showed 58 on the car's computer). The second tank, over 300 miles, was down at 48.8 and I think I am in late 40s on this current tank. When I do fill up my overall mpg will almost certainly dip below 50.

To be fair, it's the most economical car since my VW Golf Diesel and the most economical petrol car by some distance. I must stop being so competitive about mpg figures :)
Title: Re: MPG for those interested
Post by: John Ratsey on February 16, 2022, 11:22:49 AM
I've said more than once that IMHO Honda should have designed the electrically powered aircon to be reversible so it could be used as a heatpump. This would have reduced the adverse effects on mpg caused by the engine running under sub-optimal conditions* to provide heat (enabling Eco mode reduces this problem by allowing a bigger difference between target and actual cabin temperatures so it lets the engine stop more often). I've been using the seat heating for the first few miles of any journey or in urban driving with cabin heating only used on longer runs or to clear the windows. I would have also liked to have blocked off most of the front grille but found that to be a challenge. If the standard fuel efficiency tests included a proper cold weather component then vehicle manufacturers would have more incentive to address the cold weather problem.

My Crosstar claimed 61 mpg on a 6 mile trip across town on Monday (temperature about 9C) and 79 mpg on the return home about an hour later. The mpg on short trips can be strongly influenced by the difference in battery charge between start and end but starting the return journey with a warm engine would have helped.

*See for an excellent explanation of the design philosophy.
Title: Re: MPG for those interested
Post by: peteo48 on February 16, 2022, 02:30:34 PM
Interesting John. I do know, that amongst EV early adopters, pre-heating and/or using the heated seats were seen as  ways of reducing the effect of cold weather on range. My pal still has his 2014 Nissan Leaf and he does the preheating thing via an app on his phone on cold days. He uses AC to clear the windows if misted up.
Title: Re: MPG for those interested
Post by: peteo48 on February 17, 2022, 11:44:00 AM
Feeling a bit better about mpg this morning. I've found a similar car to mine on spritmonitor who has an overall mpg over just over 50 but, since October, this car has travelled around 1500 miles and hasn't once registered a tank of 50 mpg or more - mostly mid to late 40s.

What was instructive about this car's figures was a bell shaped curve from early 2021 to early 2022. Poor mpg at both ends but much better mpg from, say, April through to October.

So I'm now thinking 48 mpg isn't that bad and I may get to late 50's in the warmer weather. If I record a 60 mpg tank at any stage I will be buying champagne!
Title: Re: MPG for those interested
Post by: Pine on February 19, 2022, 02:09:21 PM
When I had a new Fiesta I noticed an improvement in MPG when I passed 2000 miles.  I had the same from my Corolla when I passed 4000 miles. Given that the engine in the Corolla only runs 50% of the time then that would be similar to the Fiesta.  With electrical assistance hybrid engines are less stressed than normal ICEs.  There is a guy on the Toyota forum who has an Auris that has done in excess of 150000 miles and he says his fuel consumption is still as good as it ever was.

I think the Honda and Toyota hybrid systems are the best around.  Most other manufacturers have mated their hybrids to a DGS gearbox, a potential source of problems in the years ahead as most drivers treat them like conventional automatics.
Title: Re: MPG for those interested
Post by: corbett on February 22, 2022, 06:35:09 PM
Had my ex for 4 weeks now just completed 500 miles
Today went from Nottingham to Bakewell, approx 50% on motorway and the rest on minor roads,  a steady 55 - 60 mph on motorway, achieved 58.2mpg.
On way back same route similar speed and driving conditions, this time 82.5 MPG.
Can only assume was to do with wind and gradient.
Lovely drive and used ACC  just on motorway no problems at all.
Title: Re: MPG for those interested
Post by: peteo48 on February 25, 2022, 11:00:45 AM
Just filled up only because I had a Nectar card offer that was about to expire. 48.5 mpg just a tad down on the last fuel up but my 50 plus mpg status overall is just preserved. Hoping for better mpg going forward as the weather warms up. I wonder how much per litre my next fill up will be? £2 per litre perhaps?
Title: Re: MPG for those interested
Post by: John Ratsey on February 26, 2022, 06:23:25 AM
I wonder how much per litre my next fill up will be? £2 per litre perhaps?
And that's when spending money on a car with better mpg starts to show up in the household finances. :)
Title: Re: MPG for those interested
Post by: Kenneve on March 15, 2022, 09:57:10 AM
Current total mileage today, since April 21 =  7336 miles, Fuel consumption over that distance = 65.9MPG
Driving style: Mostly 'B' mode except where ACC is required, (which is not often).  ECO = Off

I have to confess that only about 12-15% of those miles are motorway miles and then generally circa 65Mph.
Most motoring is urban/country roads where speed limits are 50mph or less.

These figures are from the dashboard readouts, not really concerned about any errors in quoted/real results, since all my previous Jazz cars have used the same basis for consumption comparison.
Typically, they were usually in the mid 50s Mpg, so more than happy with the MK4 improvements.

Have now turned the 8000mile mark, which I guess now covers most of the Winter period, consumption over that mileage is still returning 66.0mpg, so still very pleased with results.

Title: Re: MPG for those interested
Post by: sportse on March 19, 2022, 12:42:00 PM
With the warmer weather, I managed 77.1mpg today over 17 miles of mixed 30/40/50/60 country and urban roads.

Car was already warm from previous trips today, I've noticed the engine doesn't always start up recently as it's not needed for heating with the warmer temperatures.
Title: Re: MPG for those interested
Post by: Jazzik on March 19, 2022, 02:21:48 PM
With the warmer weather, I managed 77.1mpg today over 17 miles of mixed 30/40/50/60 country and urban roads.

 But of course you do realize that that consumption over such a distance means nothing, literally nothing at all?
Example: We drove an almost identical trip of 22.5 kilometers (almost 14 mi) this morning. Start with COLD engine, air temperature + 7 įC, almost no wind.
Consumption according to BC: 3.4 l/100 km. = 83.1mpg.
Knowing that BC is a bit of a liar, I assume that the actual consumption was about 3.6 l/100 km. (78.5mpg)...
Unfortunately now the real world: the actual measured consumption of our Jazz over almost half a year is
4.49 l/100 km. = 62.9mpg. Almost 20 mpg less...
Title: Re: MPG for those interested
Post by: sportse on March 19, 2022, 04:00:02 PM
My long time average over 12,000 miles is almost exactly 50mpg.

Due to most driving being steady 70mph trips.


Good compared to other petrol cars with similar performance.
Title: Re: MPG for those interested
Post by: John Ratsey on March 21, 2022, 06:34:32 PM
Spring seems to be arriving. For a trip across town (about 6 miles each way) my Crosstar reported 68.8 mpg on the outgoing journey and 93.4 mpg for the homeward leg about 1 1/4 hours later. There was no need for heating and the battery gauge was 4 bars when I started and finished (I didn't check it at the other end of the trip but the charge wmay have been higher). The homeward journey was slower due to more traffic. The average according to the computer is 81.1 mpg which means upper 70's mpg after allowing for the optimism.
Title: Re: MPG for those interested
Post by: sportse on April 07, 2022, 04:31:43 PM
My range display always shows around 400 - the only time I have seen more was when I first bought the car and also after a recent full power reset... where it shows 600 miles!

Looks like the computer is programmed to assume a high mpg when fully reset, I expect it to drop back down to the long term 400 miles range after a few tanks of fuel.
Title: Re: MPG for those interested
Post by: Kremmen on April 07, 2022, 05:00:16 PM
Here's my 199.9 :

(https://i.imgur.com/QfeDgTH.jpg)

Beat that
Title: Re: MPG for those interested
Post by: Bazzzer on April 07, 2022, 08:55:44 PM
Here's my 199.9 :

Beat that

I had that in my Mk3 once after driving out of a car park and trundling 1.5 miles downhill.
Title: Re: MPG for those interested
Post by: sportse on April 09, 2022, 08:53:05 AM
Here's my 199.9 :

(https://i.imgur.com/QfeDgTH.jpg)

Beat that
Beat that ;)

(https://uploads.tapatalk-cdn.com/20220409/6de9e2983324f36b3b020cba471f76be.jpg)
Title: Re: MPG for those interested
Post by: Pixie 22 on April 10, 2022, 07:31:48 PM
Iím getting about 70mpg on country roads between Edinburgh and Kelso, which is 43 miles in length :)
Title: Re: MPG for those interested
Post by: sportse on April 10, 2022, 09:06:16 PM
A 50 mile round trip on the motorway today - fully loaded on the way out with 5 adults and suitcases, and just me on the return.

Up some hills on the motorway too, just under 53mpg was quite good for the whole trip from a cold start.

Acceleration a bit slower, but not much mooing if you use the trick of only pressing 1/3 of the way and holding. Braking a bit longer with all the weight, but not too bad.
Title: Re: MPG for those interested
Post by: Lord Voltermore on April 11, 2022, 05:00:53 PM
Just  done a  run, from cold start. approx 10 miles in town, about half was  fairly gentle, but some   stop start traffic  and I had to stop at about  8 sets of traffic lights.  Then about  5 miles  suburban 40 mph limit.    Then 3 miles on country  A road , 50 -60 mph,  and about 10 miles  on  narrow country lanes , mostly under  30 mph, often having to slow or stop for oncoming cars.   ( I even got the occasional RDMS twitch   ;D)

 I wasnt trying to be specially frugal. Just went with the traffic flow.   76 mpg  on the fibometer. !!  :-*
Title: Re: MPG for those interested
Post by: peteo48 on April 11, 2022, 05:51:54 PM
Lots of regen braking?
Title: Re: MPG for those interested
Post by: Kremmen on April 12, 2022, 05:41:37 AM
In the next couple of months the M4 roadworks 50mph limit will be removed and I'll be closer to 60mph 65mph so I'll be out of the mpg race.
Title: Re: MPG for those interested
Post by: Lord Voltermore on April 12, 2022, 02:03:07 PM
Lots of regen braking?
No long hills.  All in D mode. Eco off.    I do try to anticipate the need to slow or stop, so maybe I'm slowing more on regen engine braking, and lighter on brakes than some. 

I think climate control was off, which will also have helped.
Title: Re: MPG for those interested
Post by: shufty on April 12, 2022, 03:30:40 PM
...I have Econ on (apart from for traffic light grand prix and roundabouts :D), B mode (apart from ACC) and pootle at normal speeds 30, 40, 50 etc. and  from 60 to 70ish ;) on the dual carriageway. 20 min, 17 mile journey each way to work every day, various journeys at the weekend although no great distance.
Climate control is on 99% of the time.
Car reckons I'm getting 66.9mpg at the moment. Seems to plateau occasionally but mainly slowly drops as the tank empties.
Warmer weather making a noticeable difference. Week or so ago was only 57ish.
Will see what I end up on by the end of this tank.
Title: Re: MPG for those interested
Post by: Pixie 22 on April 12, 2022, 05:11:03 PM
I'm getting about 71mpg on a mixed roads between Edinburgh and the Scottish Borders, not exceeding 55mph.
Title: Re: MPG for those interested
Post by: Roman on April 12, 2022, 05:51:44 PM
We in Israel have now nice temperature outside - 19-21 degrees Celsius, ECO switched off used D mode in urban drive 30-50km/h ~10km trips, constantly getting from fibometer 3,1l/100km every trip, now driven 342km from full tank with average 3,2l/100km
But that 3,1l/100km can be in reality something between 3,1-3,19l/100km
Sad that I canít switch to km/l readingÖ.
Title: Re: MPG for those interested
Post by: sportse on April 16, 2022, 07:52:54 PM
Some good mpg figures around at the moment with lots of EV running as the engine isnít needed for heat. Itís shutting off very quickly after start.

I did a 25 mile trip today, country/urban roads 30-60 mph. 77 mpg is pretty good, not driving for economy just normal with the traffic.

(https://uploads.tapatalk-cdn.com/20220416/13b77cac139ac6aa21527ac94ae0a05a.jpg)
Title: Re: MPG for those interested
Post by: PaulC on April 16, 2022, 10:23:55 PM
Hi Sportse,
what did you do to get trip fuel consumption displayed on the Trip Meter?
Thanks
Title: MPG for those interested
Post by: sportse on April 17, 2022, 04:34:51 AM
Hi Sportse,
what did you do to get trip fuel consumption displayed on the Trip Meter?
Thanks
Itís from the Honda app through telematics.

Itís gallons used, Honda still hasnít updated the units and thinks itís litres. The fuel used figure isnít always right but mpg is.

App mpg agrees to the dash and on my car is almost spot on when compared to a full tank manual calculation.
Title: Re: MPG for those interested
Post by: DJazzNZ on April 18, 2022, 12:00:49 AM
After having my car for 1 week, here's what I got. I'm not really technical and really do not know what "Fuel Efficiency" looks like, but here's what showing on my car.

(https://live.staticflickr.com/65535/52012055250_fd6c063bb1_4k.jpg) (https://www.flickr.com/gp/danskiedijamcojr/KGFv9Z)

(https://live.staticflickr.com/65535/52010513077_fc6812b368_4k.jpg) (https://www.flickr.com/gp/danskiedijamcojr/KGFv9Z) (https://www.flickr.com/gp/danskiedijamcojr/27MJL4)
Title: Re: MPG for those interested
Post by: Marmoset on April 18, 2022, 12:51:33 AM
After having my car for 1 week, here's what I got. I'm not really technical and really do not know what efficiency looks like, but here's what showing on my car.

(https://live.staticflickr.com/65535/52012055250_fd6c063bb1_4k.jpg) (https://www.flickr.com/gp/danskiedijamcojr/KGFv9Z)

(https://live.staticflickr.com/65535/52010513077_fc6812b368_4k.jpg) (https://www.flickr.com/gp/danskiedijamcojr/KGFv9Z)
 (https://www.flickr.com/gp/danskiedijamcojr/27MJL4)
If you're used to mpg figures, the upper image for trip B works out at 76mpg. Your ''current drive'' works out at a higher 78mpg figure.  km/pl equivalents 27 and 28 respectively. Healthy figures, I'd say.  Though, of course, that's economy rather than efficiency.
Title: Re: MPG for those interested
Post by: Kremmen on April 18, 2022, 02:44:44 AM
I find it unusual that the change from winter to summer causes so much mpg change.

I do roughly the same journey every weekend and winter has been giving me an average 60mpg whereas spring is giving me an average 70mpg.

On one particularly warm day a few weeks ago, outside temp 18C, I got almost 80mpg.

My Civics seasonal change was only about 5mpg.
Title: Re: MPG for those interested
Post by: sportse on April 18, 2022, 08:11:20 AM
Iím surprised the manufacturers of hybrids havenít come up with a more efficient way to heat the cabin in winter than running the petrol engine.

My mpg has seen a big jump just recently with the warmer weather, and the car is driving much more in EV mode - very noticeable at lower speeds.
Title: Re: MPG for those interested
Post by: peteo48 on April 18, 2022, 01:15:26 PM
I'm finding the increase in mpg is quite noticeable as well. I often start off in EV mode (when the car has been used and then parked whilst going to the supermarket say). In the colder weather this never happened.

I've mentioned this before but I have found a driver on spritmonitor whose mpg is an almost perfect "bell" curve on a graph and I think I am following this example. This driver almost never got 50 mpg after November or until the following spring but peaked at over 60 mpg in the summer. He had an overall average of just over 50 mpg. I think he looks like a high mileage driver so that will be a factor if cruising at 70 mph.

I'm showing 59 mpg on my current tank. I think this will be about 55 to 56 actual.
Title: Re: MPG for those interested
Post by: Roman on April 19, 2022, 06:12:52 PM
Iím surprised the manufacturers of hybrids havenít come up with a more efficient way to heat the cabin in winter than running the petrol engine.

My mpg has seen a big jump just recently with the warmer weather, and the car is driving much more in EV mode - very noticeable at lower speeds.
One hybrid that uses heating elements I know but that car not selling in Europe
Itís Nissan e-Note with 1,2l petrol engine that always working as generator.
Title: Re: MPG for those interested
Post by: Marmoset on April 22, 2022, 11:34:21 AM
I've had an EX since December 2020 and driven around 10,000 miles in it.  The mpg for last 3,000 or so miles is just over 66mpg but that figure is steadily rising - warmer weather plus slight modifications in my driving style. I seem to have settled into driving in B (figuring that the regenerative braking will reduce brake wear as well as save a little fuel) and with the econ button on.  I will often sit behind a lorry at circa 58mph for extended periods until I get bored looking at the rear of the same container, when I'll overtake.  Then I'll usually settle behind another truck for a while and repeat the process.  This makes for low-stress, reasonably economical driving for me.  Currently I'm averaging just over 70mpg. 
Title: Re: MPG for those interested
Post by: aphybrid on April 22, 2022, 12:06:45 PM
Rural driving with occasional motorway to airport.
Tried tank fills with all D mode, all B mode both with econ.
Recently switched to start in B and when road allows constant speed go to D and set cruise (53mpg as this allows constant round most bends on routes used and hill sections minimises mooing) then return to B for urban times. Motorway cruise on 70mph.

This has resulted in an increase in overall mpg from new so far by about 1mpg but last fill gave highest for one fill so far of 57.31mpg.

Looks like I will settled on these methods.
Title: Re: MPG for those interested
Post by: peteo48 on April 22, 2022, 01:15:47 PM
57.5 mpg from latest tank. I am pretty sure this is the highest mpg I have ever recorded on any car albeit only by 1 mpg or so. Most of my driving has been in "B" mode with ECON mode selected. Did some motorway driving yesterday and I prefer "D" with Econ off for this type of driving.

PS

The old "4 mpg" optimistic thing was evident again. The fibometer said 61.5 mpg. To be honest I don't really need to record my mpg at all given how constant the 4 mpg thing is.
Title: Re: MPG for those interested
Post by: Jazzik on May 01, 2022, 08:32:49 PM
Today a short, about 40 km. (25 miles) trip with Mrs. Jazzik. Beautiful weather, 18įC and hardly any wind. Half way through we stopped for a half hour walk in the woods. We did not drive faster than 80 km/h (50 mph).
Back home, the BC showed a fuel economy of 3.3 l/100 km (85.6 mpg). I always correct the (usually over-optimistic) BC and assume a real consumption of 3.5 l/100 km = 80.7 mpg.
Not bad... the fuel tank is now about half empty and just a shame ;) that I see a consumption of 4.5 l/100 km (62.8 mpg) this far from the last fill up on the BC....
Title: Re: MPG for those interested
Post by: Kremmen on May 02, 2022, 04:57:07 AM
It does seem that up to 50mph you can get some impressive mpg, especially in warmer weather. Once over 50mph and closer to 70mph mpg drops dramatically.

Looking back to that Honda video about the h:ev efficiency, widely linked to here, the cutoff point on that was 49mph when converted from the kph used in the video.

The posted results here, and what I'm getting, have been :

50mph = 70mpg
60mph = 60mpg
70mph = 50mpg
Title: Re: MPG for those interested
Post by: John Ratsey on May 02, 2022, 09:13:20 PM
It does seem that up to 50mph you can get some impressive mpg, especially in warmer weather. Once over 50mph and closer to 70mph mpg drops dramatically.
I suspect that above 50mph the power output from the engine is outside the zone of optimum efficiency plus the drag losses start to shoot up (approx double at 70mph compared to 50mph). I reckon the roof rails on my Crosstar don't help and cause significnat excess drag if there's a crosswind. The Jazz is evidently optimised for urban and extra-urban conditions. If it was given a bigger engine with the optimum efficiency at higher power then I expect that the mpg under low power conditions would suffer. It will be interesting to see the real life numbers for the new Civic and I wonder if Honda will make it more tolerant of cold conditions.
Title: Re: MPG for those interested
Post by: Kremmen on May 10, 2022, 05:20:54 AM
I was always dubious about the Which? test claim that they got 91mpg out of their test car.

Yesterday I did a rare local urban trip. This involved 30mph and Ealing councils blanket 20mph limit and the result of this 9 mile 20 & 30mph trip was 130mpg !

(https://i.imgur.com/5Ep6b7q.jpg)
Title: Re: MPG for those interested
Post by: Roman on May 11, 2022, 05:02:54 AM
Hi Kremmen
Do you remember car presentation ?
They told during the presentation that car running in EV mode 80% of time with speed 40km/h
An if we check  Japanese Honda site they have in addition to WLTP Test result also JC08 test result
In JC08 test they get maximum 100MPG (2,8l/100km)
And if we look on JC08 test pattern we will see that most of test time car run on such low speeds and only small part of this 15 minutes test car run with speed of 80km/h (50mph)
Title: Re: MPG for those interested
Post by: Kremmen on May 11, 2022, 05:58:42 AM
Morning

All I know is what I said above. I never got above 30mph and a lot of it was at 20mph. I suspect if I'd driven longer that would have dropped as the battery needed more topping up.
Title: Re: MPG for those interested
Post by: Roman on May 11, 2022, 07:21:42 PM
Aaa, maybe you get fuel economy 130 MPG because  battery on start has -50% charge and maybe engine already hot enough.
I also get readings like this (around 2,5l/100km) sometimes when I starting new trip when  engine already at itís working temperature and battery has more then 30% charge (sorry 3 bars on battery meter) but same 3 bars can be from 25% to 42% charge.
My every day trips is same route with same speed around 40 km/h with maximum speed up to 50km/h, with glide weíre itís possible after ice engine stopping work to charge battery, I constantly getting readings 3.0l/100km - 3.3l/100km with average on tank for  more then 300 km 3,2l/100km, but there is catch - such fuel economy possible when trip not shorter then 8 km in summer or 15-20 km in winter (+10 degrees C) if I starting that trip with cold engine.
First year of car owning i not known that and for several months did relatively short trips ~ 2-3km and my average fuel consumption was 3,8- 4,3l/100km.
Title: Re: MPG for those interested
Post by: John Ratsey on May 13, 2022, 12:12:00 PM
My Crosstar is liking the warmer weather. Yesterday afternoon I did a trip totalling 91 miles using mainly rural A roads, rarely reaching 60mph, with some much slower sections and an average speed of around 35 mph. The trip was in two parts, 26 miles where the car claimed 92.7 mph and a second part of 65 miles with a claimed 79.8 mpg. The journey was assisted by a light tail breeze, the first part included a slight height drop but was fairly level overall while the second part was through more undulating terrain with an overall height gain. The engine had been off for two hours before the start and the ambient temperature was such that neither heating nor aircon was needed.
Title: Re: MPG for those interested
Post by: PTJAZZ on May 13, 2022, 01:59:27 PM
A couple of days ago a took a photo of my BC total average consumption as I am arriving 10.000 Km and donīt know if the BC resets the values.

On close to 9500 Km BC indicates 3.3L average and real SM 3.53L

It is like a 125 cc Scooter... ;D ;D
Title: Re: MPG for those interested
Post by: sportse on May 14, 2022, 10:09:50 PM
Speed makes a huge difference- this shows two trips on country roads likely averaging 40mph and two trips on the motorway at 70mph:

(https://uploads.tapatalk-cdn.com/20220514/fa6dbb15b76d9572ced2151ec86d2ee5.jpg)

Iíve tried various things but when you are at 70mph there is hardly any difference to the mpg you get. Likely because most of the time the petrol engine is in direct drive mode and running.
Title: Re: MPG for those interested
Post by: Kremmen on May 15, 2022, 05:10:05 AM
Yep, our model of Jazz doesn't give optimal over 49.71mph (80kph)
Title: Re: MPG for those interested
Post by: John Ratsey on May 15, 2022, 08:19:23 AM
Iíve tried various things but when you are at 70mph there is hardly any difference to the mpg you get. Likely because most of the time the petrol engine is in direct drive mode and running.
I suspect it's a combination of a body shape which isn't very aerodynamic and the engine running well outside the zone of maximum efficiency in order to deliver the required power. I wouldn't be surprised if the new Civic with its 2 litre engine will give better mpg than the Jazz at 70mph (but worse at lower speeds).
Title: Re: MPG for those interested
Post by: ColinB on May 15, 2022, 08:47:50 AM
Iíve tried various things but when you are at 70mph there is hardly any difference to the mpg you get. Likely because most of the time the petrol engine is in direct drive mode and running.
I suspect it's a combination of a body shape which isn't very aerodynamic and the engine running well outside the zone of maximum efficiency in order to deliver the required power. I wouldn't be surprised if the new Civic with its 2 litre engine will give better mpg than the Jazz at 70mph (but worse at lower speeds).
Plus the fact that when in direct drive the battery and electric motors are just dead weight. The Mk3 actually gives better mpg at motorway speeds ... but worse around town.
Title: Re: MPG for those interested
Post by: John Ratsey on May 16, 2022, 10:47:14 AM
Plus the fact that when in direct drive the battery and electric motors are just dead weight. The Mk3 actually gives better mpg at motorway speeds ... but worse around town.
Although there's the weight saving of having no conventional gearbox.

As for the mpg, I've looked up the official data for the WLTP tests (conducted at 23C - an untypical temperature for UK). The numbers below are the mpgs for the low / medium / high / extra high cycles = the combined result.
2019 Jazz SE manual transmission: 40.9 / 53.3 / 56.5 / 44.8 = 48.7
2019 Jazz SE CVT transmission:      37.2 / 53.3 / 56.5 / 47.5 = 47.9
2020 Jazz SE eCVT transmission:     80.7 /74.3 / 72.4 / 48.7 = 62.8

Which show that the Mk 4 gives slightly better mpg than the Mk 3 at motorway speeds but the numbers also highlight the massive drop-off in the Mk 4's mpg between the high and extra high cycles. The corresponding reduction for the Mk 3 is much less.  The WLTP procedure is described at https://en.wikipedia.org/wiki/Worldwide_Harmonised_Light_Vehicles_Test_Procedure .
Title: Re: MPG for those interested
Post by: Roman on May 16, 2022, 06:08:11 PM
Maybe I wrong, but I think that low mpg on high speed came from single speed gearbox, there Toyota wins with planetary gearbox Ö.
Title: MPG for those interested
Post by: sportse on May 16, 2022, 06:21:35 PM
Iíve had a couple of Toyota hybrids - an Auris and a Yaris.

Motorway mpg was similar to the Jazz slightly less in the Auris, maybe 2mpg less ,and 5 mpg more in the Yaris.

The Yaris was underpowered above 50mph though, despite having similar horsepower as the Jazz.

Although the Jazz only officially has 108hp, the performance is similar to other 130-150hp cars on the motorway.

The equation they use to calculate equivalent horsepower in a hybrid doesnít match the actual performance you get from one in the ones Iíve had.
Title: Re: MPG for those interested
Post by: John Ratsey on May 16, 2022, 06:25:06 PM
Maybe I wrong, but I think that low mpg on high speed came from single speed gearbox, there Toyota wins with planetary gearbox Ö.
The car will only use direct drive if it's the most efficient option. If more power is needed than can be efficiently delivered by direct drive then the system will switch back to generator - motor mode. This can be seen by watching the power flow display. I suspect that Honda engineers focussed too much on tuning the system to suit their expected usage (predominantly urban driving). There might be a system tweak when the mid-life refresh arrives (next year?). The money problem with the combined emissions total is explained here https://clubjazz.org/forum/index.php?topic=14648.0 .
Title: MPG for those interested
Post by: sportse on May 16, 2022, 06:29:13 PM
Yes, the computer in the jazz seems programmed for low speed efficiency.

You can get good, mostly quiet performance on the motorway but have to drive around the programming.

Iíve found pressing the accelerator 1/3 of the way and holding it there gets you good acceleration at high speed after only a short delay.

Whereas pressing the pedal a long way gets you nothing for what seems like ages before the computer decides to accelerate.

A mode switch with sport/normal/eco like the HRV would be useful.
Title: Re: MPG for those interested
Post by: PaultheManc on May 18, 2022, 10:28:28 AM
First refilled to full tank since acquiring my MkIV.
Car system reported 61.2 MPG, actual physical calculation 59.5 MPG.  Did 470 miles before refilling, one bar left on the fuel gauge.
About 15% of mileage short local trips, rest on A or Motorway (averaging about 62 mph).
Best ever tank filled average in my previous MkII was 54.7 MPG which was mainly a long run down a quiet A9 with cruise control set at 60 in Summer.
Title: Re: MPG for those interested
Post by: Kenneve on May 24, 2022, 05:03:33 PM
Current total mileage today, since April 21 =  7336 miles, Fuel consumption over that distance = 65.9MPG
Driving style: Mostly 'B' mode except where ACC is required, (which is not often).  ECO = Off

I have to confess that only about 12-15% of those miles are motorway miles and then generally circa 65Mph.
Most motoring is urban/country roads where speed limits are 50mph or less.

These figures are from the dashboard readouts, not really concerned about any errors in quoted/real results, since all my previous Jazz cars have used the same basis for consumption comparison.
Typically, they were usually in the mid 50s Mpg, so more than happy with the MK4 improvements.

Have now turned the 8000mile mark, which I guess now covers most of the Winter period, consumption over that mileage is still returning 66.0mpg, so still very pleased with results.

Just turned over the 10020 miles mark today  and still showing circa 67.0mpg, ( see the trip B result)
It seems that the trip B figure on the dashboard only reads to 4 digits, hence it is reading 20.3 miles instead of 10020 miles.
I've also included a photo of the trip A results for the last 3 refuels, which I think show fairly consistent results.
Still well pleased with the vehicle. ;D
Title: Re: MPG for those interested
Post by: 1KPI on May 26, 2022, 11:00:24 AM
Speed makes a huge difference- this shows two trips on country roads likely averaging 40mph and two trips on the motorway at 70mph:

(https://uploads.tapatalk-cdn.com/20220514/fa6dbb15b76d9572ced2151ec86d2ee5.jpg)

Iíve tried various things but when you are at 70mph there is hardly any difference to the mpg you get. Likely because most of the time the petrol engine is in direct drive mode and running.

An interesting post
Could you please tell me how you got the trip computer on the main screen?
Title: Re: MPG for those interested
Post by: 1KPI on May 26, 2022, 11:24:01 AM
Sorry incomplete post
Trip computer as a short cut
I cannot see it as any of my tabs
Title: Re: MPG for those interested
Post by: Kenneve on May 26, 2022, 12:09:38 PM
For Trip Computer on main screen:- Go to - Home - Cursor right - Trip computer.
In my case Trip A is set, to reset at Refuelling, so it give the current situation plus the last 3 refuels.
Trip B is set to Manual reset and has not been touched since the car was new, hence it gives total mileage with consumption to match.
Title: Re: MPG for those interested
Post by: 1KPI on May 26, 2022, 02:45:48 PM
Excellent!
Thanks for the prompt advice
Sometimes you look but donít just see!
Really v pleased with the Crosstar which Iíve had for 2 months now
The real ( brim to brim ) fuel consumption has been more than 60mpg under all driving circumstances which, given rising fuel costs, has been one of many benefits of getting the car.
The only readjustment I have had to make is realising the compact external dimensions given the spaciousness inside
Title: Re: MPG for those interested
Post by: sportse on May 26, 2022, 02:59:50 PM
I currently have a crosstar loan car - I'm finding maybe 5 mpg more on the motorway.

Perhaps the tyres on the crosstar have lower resistance than the standard EX tyres?

I found the standard EX tyres to be better in the wet, but in the dry the crosstar tyres are more comfortable.
Title: Re: MPG for those interested
Post by: Expatman on May 26, 2022, 03:30:37 PM
But that's more down to the make and type of tyre, not the car. As a generalisation All Season tyres are said to give a softer ride, however, only Fallen make an All Season tyre for the Crosstar - it's a rare size - so replacement is limited.
Title: Re: MPG for those interested
Post by: Lord Voltermore on June 06, 2022, 01:04:37 PM
Here are trip computer figures for my Jazz EX on its current continental road trip.  Summer tyres, aircon on.

One shows it in mpg  ,the other the same figures   in litres per 100 km   '
Prev  3' is A roads, no motorway  , includes crossing the Brenner pass from Austria into Italy.   For much of this trip the average was 88 mpg.
Prev 2'  is  A roadsc, crossing a mountain pass and approx  25% on  motorway
Prev 1'  is in  A roads and about 70 % of it on  motorway 
Current is A roads.  No motorway

Motorways were fairly leisurely  - maybe 60 -65mph, but faster  at times .

I am very pleased with these results. Average from new  (5263 miles )is 67.9 mpg
Title: Re: MPG for those interested
Post by: jamjar on June 06, 2022, 04:15:23 PM
I currently have a crosstar loan car - I'm finding maybe 5 mpg more on the motorway.

Perhaps the tyres on the crosstar have lower resistance than the standard EX tyres?

I found the standard EX tyres to be better in the wet, but in the dry the crosstar tyres are more comfortable.
Title: Re: MPG for those interested
Post by: sportse on June 06, 2022, 05:44:19 PM
It seems that speed makes a massive difference to MPG - at 70mph it's around 50-55mpg no matter what you do.

But if you don't use the motorways then it's easy to get 70+ mpg.

Considering the performance, it's a great achievement for performance/mpg.
Title: Re: MPG for those interested
Post by: Roman on June 06, 2022, 11:03:52 PM
Best speed for mpg is 50-57 mph.
Once you over this speed you waste energy  because of  air drag.
How can we reduce air drag ?
Title: Re: MPG for those interested
Post by: Kremmen on June 07, 2022, 05:39:48 AM
I'm finding, as per the Honda Hybrid explanation video frequently linked to, that over 49mph / 80kph is the point where mpg starts to reduce.

My local motorway has had a 50mph limit for a long time and at 50mph I'm getting ~70mpg but where the motorway restriction ends and I speed up to 60mph the mpg instantly decreases.
Title: MPG for those interested
Post by: sportse on June 07, 2022, 06:34:01 AM
Best speed for mpg is 50-57 mph.
Once you over this speed you waste energy  because of  air drag.
How can we reduce air drag ?
We already have the Ďspeed noseí on the EX instead of the crosstarís ordinary grille , so are probably at the limit already for the body shape and ride height.
Title: Re: MPG for those interested
Post by: sportse on June 07, 2022, 06:35:59 AM
I'm finding, as per the Honda Hybrid explanation video frequently linked to, that over 49mph / 80kph is the point where mpg starts to reduce.

My local motorway has had a 50mph limit for a long time and at 50mph I'm getting ~70mpg but where the motorway restriction ends and I speed up to 60mph the mpg instantly decreases.
Yes, 50mph motorway sections are great for mpg.

Iíve achieved 74mpg on a trip that was mainly steady 50mph motorway.
Title: Re: MPG for those interested
Post by: Roman on June 17, 2022, 09:58:32 AM
(https://i.ibb.co/YcWd2VG/D5-FCBC68-770-C-4-B0-A-9547-7214-DD347-A37.jpg) (https://ibb.co/y6Rk0xJ)trip A
(https://i.ibb.co/56wt25T/FF5904-C1-DD59-441-B-AC31-A96-B08-AF83-AD.jpg) (https://ibb.co/7XL8bGv)trip B
MPG on photo trip A total average after topping tank to full, there lower average MPG because first 4 trips needed to use climate control with temp set to 25 degree C (outside temp 29 degree C) and this trips  shorter than 10 mile.
MPG on photo trip B in town with max speed 25 MPH without A/C.
Key to fuel economy - right speed (in town if there every 500m runabout or trafic light it`s 25 mph) and avoid short trips, best result on trips 10 miles or more, coast  (glide) as much as possible, if acceptable drive up the hill at a slightly lower speed, so we will use less energy from the battery and the generator will turn on much later, smart usage of A/C or climate control and when acceptable use only fan with choice of air from outside.
if you want  call me captain snail, I understand that almost no one will drive a car like that, but nevertheless here it is the result - consumption of only 104.4 miles per gallon on fairly even road, all trips were started with the battery charged to 3-4 bars (specially I didnít charge the battery because it worsens the average consumption per tank) when charging while standing still, about 2 kilowatts out of 5 that the internal combustion engine consumes are lost to heat.
Title: Re: MPG for those interested
Post by: Kremmen on June 17, 2022, 10:05:23 AM
I'll be doing my regular 30 mile motorway trip tomorrow morning. Be interesting to see how the temps affect it.
Title: Re: MPG for those interested
Post by: aphybrid on June 23, 2022, 09:44:28 AM
Modifying driving settings to find best mpg has resulted in use of B mode + ECCO as standard with D mode on motorway for cruise settings etc.

Overall mpg from new is currently 53.01. - 4680 miles with 416.30 litres used

See attached excel graph for mpg for each fill.

dips with m/way speed. shift to B mode giving increase evident from increase

Title: Re: MPG for those interested
Post by: Jazzik on June 23, 2022, 10:30:50 AM
I agree that driving in "B" mode and Econ saves fuel. However, I miss a timeline on your excel graph. Temperature also has a significant influence on consumption. In winter, consumption will therefore always be higher than in summer.
Title: Re: MPG for those interested
Post by: peteo48 on June 23, 2022, 10:53:15 AM
I'm on 52.4 mpg (actual not computer) at present. My lowest mpg has been 48.5 and that was in the winter months when, effectively, you are using the ICE to keep you warm.

On my current tank I am on just over 66 mpg according to the computer - I think this will pan out at 62 mpg actual. I do a very small mileage - I've had the car 8 months and have done a tad under 1300 miles. I reckon I'm on track for an overall mpg over a year of 55 ish. I'll take that. My MK3 was on about 42 mpg overall after 2 years.
Title: Re: MPG for those interested
Post by: Kremmen on June 23, 2022, 11:48:13 AM
I did my usual 30 mile trip yesterday and got just over 72mpg

What surprised me was the aircon. Unlike the Civics it did maintain a good fan speed to keep the interior cool.

Outside was 27C and I had it set to 20C

Pleasantly surprised  :)
Title: Re: MPG for those interested
Post by: aphybrid on June 23, 2022, 12:13:02 PM
I agree that driving in "B" mode and Econ saves fuel. However, I miss a timeline on your excel graph. Temperature also has a significant influence on consumption. In winter, consumption will therefore always be higher than in summer.

Sorry about cropping too much, attached graph with dates.


Also attached my Jazz Sport mpg graph which shows in the winter months decreasing mpg, all the other dips are due to m/way trips to go to airport on holidays.

Title: Re: MPG for those interested
Post by: Jazzik on June 23, 2022, 12:23:23 PM
(https://emojipedia-us.s3.dualstack.us-west-1.amazonaws.com/thumbs/120/emojidex/112/thumbs-up-sign_1f44d.png)
Title: Re: MPG for those interested
Post by: Pixie 22 on June 24, 2022, 05:22:40 PM
In the first 1650 miles in a mk4, I have averaged 76.1 according to the trip computer. This is over a mixture of roads. I don't often drive above 50mph and rarely above 60mph, always trying to avoid engine drive. The trick is to charge the battery as much as you can when slowing down or going to down hill and then using that electric reserve for fuel consumptive ascents and accelerations.
Title: Re: MPG for those interested
Post by: Kremmen on June 24, 2022, 05:33:23 PM
I still can't work out the logic.

On a quiet flat fixed speed 50mph motorway under LIM, so speed is constant, I can see the engine kick in and out regardless whether the battery bars are 3 or 7.

I would have expected 3 bars = engine, then once up to 7 bars the engine cuts out until back down to 3 bars......and so on
Title: Re: MPG for those interested
Post by: peteo48 on June 24, 2022, 05:49:41 PM
I still can't work out the logic.

On a quiet flat fixed speed 50mph motorway under LIM, so speed is constant, I can see the engine kick in and out regardless whether the battery bars are 3 or 7.

I would have expected 3 bars = engine, then once up to 7 bars the engine cuts out until back down to 3 bars......and so on

Pretty much mirrors my experience.
Title: Re: MPG for those interested
Post by: aphybrid on June 25, 2022, 06:40:02 AM
Seems to a lot of angst about mpg, indicated on dash and engine/motor power distribution.

In the end overall the real mpg comes down miles covered and fuel put in. I always fill to full and make notes on anything like type of journey covered - high speed m/way seems to be biggest effect.

The "magic" of how the power unit manages this just has to be accepted surely and enjoy the driving experience
Title: Re: MPG for those interested
Post by: John Ratsey on June 25, 2022, 07:16:19 AM
I still can't work out the logic.

On a quiet flat fixed speed 50mph motorway under LIM, so speed is constant, I can see the engine kick in and out regardless whether the battery bars are 3 or 7.

I would have expected 3 bars = engine, then once up to 7 bars the engine cuts out until back down to 3 bars......and so on
At 50mph in direct drive on flat ground the optimum engine efficiency for the rpm dictated by being in direct drive means that there's a little spare power which trickles into the battery. Once the battery is up to 7 bars the engine has a short snooze.
Title: Re: MPG for those interested
Post by: Kenneve on June 25, 2022, 10:22:57 AM
I've said it before, but I'll say it again, it doesn't really matter how the optimum fuel consumption is arrived at. nor does it matter if certain journeys are down to the 40-50mpg range. or even up to the 80-90mpg range.
I just leave it to the Honda boffins to determine the most efficient mode, although like most members I assume that the most miles in EV mode will equal the best consumption.
To that end, I mostly drive in 'B' mode to promote maximum regeneration where possible and for me 'Econ' mode takes the edge off the performance. so I leave it Off.

No, what matters is the overall mileage covered, against fuel used, which for me as the attached photo shows is today 10727 miles at 67.6mpg ( the 'B' trip only reads to 3 decimal places, hence it only shows 727.8 miles), however I can assure everyone that it was set when the car was new and has not been reset at any time.

I guess I should say, that most of my motoring is journeys in the 10-15 mile range, urban and semi urban, with little motorway use
And so, having had 5 Jazz cars, all automatic (1 I-shift & 3 CVT) this MK 4 EX is the best car yet, particularly with fuel costs as they are at the moment.
Title: Re: MPG for those interested
Post by: peteo48 on June 27, 2022, 11:45:39 AM
I've finally crashed through the 60 mpg barrier. Just filled up and 66.6 showing on the computer which turned out to be an actual 61.6. Mostly town driving with some country roads and motorway.

Computer 5 mpg optimistic.

First fill up since 22nd April. Could have gone quite a bit further but filled up largely for convenience. I should get at least 2 more decent tanks before the winter plunges me back under 50 mpg. I think I'm on target for an overall 55 mpg in a full year.
Title: Re: MPG for those interested
Post by: SteveM on June 27, 2022, 01:34:20 PM
So I'm a little in shock at the moment.... Figured with petrol prices as they are the time was right to see what I could get out of my EX Jazz and the results were, umm, surprising. 403 miles of mostly motorway driving over a couple of weeks with the odd trip around Milton Keynes thrown in. 23 litres of petrol. Which by my rough reckoning is near as damn it 80mpg! Nothing fancy, just driving everywhere in D with Econ mode on, a very very light foot, sensible speeds usually between 50 to 60, Apple CarPlay always on and no a/c (though I did succumb to thirty degree cabin temps a couple of times and put the fan on). Absolutely ridiculous economy and it was still creeping up when I refuelled at half a tank.
Title: Re: MPG for those interested
Post by: sportse on June 27, 2022, 02:21:56 PM
  speeds usually between 50 to 60

That's the key - mpg varies massively with speed/wind resistance.

I get 50mpg at 70mph and 70mpg at 50mph, so a big difference.

Many EV drivers sit at 55-60mph for the same reason. For them, going faster won't get them anywhere quicker as they would have to spend more time charging than they would save from the higher speed.
Title: Re: MPG for those interested
Post by: Kremmen on June 27, 2022, 03:21:53 PM
That's me  :)

Where the M4 opens up from 50mph to NSL at J8/9 westbound I only up it to 60 because anything faster kills the average MPG figure. The 7 miles I do between J 8/9 and 10 sees a small drop-off but not as drastic.
Title: Re: MPG for those interested
Post by: peteo48 on June 27, 2022, 05:00:12 PM
  speeds usually between 50 to 60

That's the key - mpg varies massively with speed/wind resistance.

I get 50mpg at 70mph and 70mpg at 50mph, so a big difference.

Many EV drivers sit at 55-60mph for the same reason. For them, going faster won't get them anywhere quicker as they would have to spend more time charging than they would save from the higher speed.

Yes - I think a lot of people, in all sorts of cars, are disappointed at mpg or range at 70 mph. People think about a long run being good for mpg - well yes but not at 70 mph.
Title: Re: MPG for those interested
Post by: Beaver on June 28, 2022, 09:20:15 AM
Having collected my car on Thursday, with 20 miles recorded, on Friday I drove about 210 miles to my weekend destination.   Setting the A meter on zero, the trip there recorded 69.0mpg on arrival.   Running around over the weekend with a mixture of town and open road driving, the A meter didn't drop below 67mpg.

On leaving to return home, I left the A meter as it was from Friday morning and zeroed the B meter before setting off, the return trip of around 210 miles recorded 74.3mpg.   Overall for the weekend, the A meter gave me 527 miles at 69.9mpg.

Compared to my 2012 Jazz that has made many similar journeys, my fuel consumption has just about halved. My driving style for the weekend was relaxed and I was happy to cruise at 55-65 mph with the Econ button selected all the time.   I used the cruise control often on the M11 and A1.

Very happy with the performance of the new model.
Title: Re: MPG for those interested
Post by: shufty on June 28, 2022, 11:01:02 AM
...On 62.5mpg at the moment. It has gone up since switching off Econ and with the warm weather, using climate control on a higher setting???
It's as though my results are back to front :D
Title: Re: MPG for those interested
Post by: Kremmen on June 28, 2022, 11:13:05 AM
There were many reports on Civinfo about getting better mpg with Eco off.

Eco dulls the throttle so maybe a heavier foot to compensate decreases mpg ?
Title: Re: MPG for those interested
Post by: peteo48 on June 28, 2022, 12:38:09 PM
I've also wondered about the ECO button thing (I have it on most of the time). There are times when you want a bit more acceleration and you might be tempted to put more throttle input whereas, without ECO, a small throttle input can result in quite a pleasing response.

I am a big fan of B mode though. Much more regen braking and, with my mainly urban driving pattern, I can take advantage of that.
Title: Re: MPG for those interested
Post by: Neil Ives on June 28, 2022, 12:44:45 PM
I am a big fan of B mode though. Much more regen braking and, with my mainly urban driving pattern, I can take advantage of that.
As part of my minimum braking style I use B when I can but ACC has to have the car in D.
Title: MPG for those interested
Post by: sportse on June 28, 2022, 12:51:14 PM
Lightly pressing the brake pedal seems to do the same thing as B mode.

I tried it out this week on the approach to a roundabout from 70mph down to 0mph.

If you put the car in B mode and lift off to slow down it charges the battery, but you get the same thing if you lightly press the brake instead.

Itís quite quick charging from 70mph - you can easily go from a half charge to fully charged when approaching a roundabout.
Title: Re: MPG for those interested
Post by: Kremmen on June 28, 2022, 12:59:06 PM
Interesting

So what gives more recharge, B mode or brakes ?

I routinely use B mode but if light braking gives more recharge I'd happily switch to D
Title: Re: MPG for those interested
Post by: sportse on June 28, 2022, 02:50:03 PM
It might be the same - I braked for the roundabout with both at about the same level of slowing down, and got about the same half charge for the battery from both of them.

On many hybrids, light braking doesn't use the actual brakes - just the electric motor.

We don't have a meter on the Jazz dashboard to see how much braking force is being used unfortunately.

On Toyota hybrids I could choose how hard to 'brake' to get maximum regeneration without wasting energy with the brake pads by using the regen meter on the dash.

There is also this useful explanation for Prius, although our hybrid systems are different:

https://prius.ecrostech.com/QandA/Brake.htm
Title: Re: MPG for those interested
Post by: Kenneve on June 28, 2022, 04:42:23 PM
I might be wrong, but I think there is a general misunderstanding, re regeneration on the Mk4 Jazz.

In my view regen occurs the moment you lift your foot off the accelerator, the car is then driving the electric motor, which becomes a generator to generate power to charge the battery.

Two degrees of regen are provided, ie 'B' & 'D' mode, with a much less degree in 'D' mode.
Use of the brake pedal provides NO additional regen braking, in fact in overall terms there is less braking energy available for regen, because that energy is then being dissipated by the friction brakes.

So, in normal driving conditions, maximum regen is provided, by lifting off the accelerator early and rolling to stop in 'B' mode, so that the footbrake is only used for the last few yards.

It's surprising how easy it is to learn this technique, which results  maximum Mpg and far less brake pad wear.
My only concern is the fact that when slowing down using regen, the brakes lights are not working, which maybe of concern to a following motorist, particularly one who is already only 6ft from my rearend!!
Title: Re: MPG for those interested
Post by: Neil Ives on June 28, 2022, 05:03:46 PM
... So, in normal driving conditions, maximum regen is provided, by lifting off the accelerator early and rolling to stop in 'B' mode, so that the footbrake is only used for the last few yards.

It's surprising how easy it is to learn this technique, which results  maximum Mpg and far less brake pad wear.
This is my preferred style of driving.
Quote
My only concern is the fact that when slowing down using regen, the brakes lights are not working, which maybe of concern to a following motorist, particularly one who is already only 6ft from my rearend!!
But isn't that the same as a conventional car deaccelerating by using the engine. A gradual slowdown shouldn't cause a rear end shunt.
If someone is too close I dab the brake pedal a few times.
Title: Re: MPG for those interested
Post by: Kremmen on June 28, 2022, 05:07:23 PM
I've found with 'thoughtful driving' approaching roundabouts and junctions in B mode, tailgaters back off because they think you have no brake lights  ;D
Title: Re: MPG for those interested
Post by: sportse on June 28, 2022, 05:41:28 PM

Two degrees of regen are provided, ie 'B' & 'D' mode, with a much less degree in 'D' mode.
Use of the brake pedal provides NO additional regen braking, in fact in overall terms there is less braking energy available for regen, because that energy is then being dissipated by the friction brakes.

In D I get limited recharging of the battery, whereas with light braking I was getting the same regen as with B while still in D.

I believe HRV may have a regen display on the dash, so you can judge how much braking to apply for maximum regen.

What we need is someone to plug into the OBD port, that way they can give us actual figures for the amount of regen each method produces and create a graph like this:

https://www.speakev.com/threads/regen-efficiency-displayed-using-the-torque-app.142183/post-2694350

Using an app, you could create your own regen gauge on a phone to ensure maximum regen.
Title: Re: MPG for those interested
Post by: sportse on June 28, 2022, 06:03:40 PM
There is unfortunately a lack of information available on the Honda hybrid system - for Prius we have loads of information on the various modes/etc.

A few comments on here may be useful - FYI regen still wastes energy as it won't be a 100% conversion of energy into the battery and there will be losses in conversion:

https://www.quora.com/How-far-can-the-brake-pedal-of-a-Toyota-Prius-be-depressed-in-order-to-engage-the-regenerative-braking-only-and-not-the-friction-brakes
Title: Re: MPG for those interested
Post by: Roman on June 28, 2022, 07:35:32 PM

Two degrees of regen are provided, ie 'B' & 'D' mode, with a much less degree in 'D' mode.
Use of the brake pedal provides NO additional regen braking, in fact in overall terms there is less braking energy available for regen, because that energy is then being dissipated by the friction brakes.

In D I get limited recharging of the battery, whereas with light braking I was getting the same regen as with B while still in D.

I believe HRV may have a regen display on the dash, so you can judge how much braking to apply for maximum regen.

What we need is someone to plug into the OBD port, that way they can give us actual figures for the amount of regen each method produces and create a graph like this:

https://www.speakev.com/threads/regen-efficiency-displayed-using-the-torque-app.142183/post-2694350

Using an app, you could create your own regen gauge on a phone to ensure maximum regen.
I did that gauge, using car scanner pro app, and Bluetooth adapter for obd
When brake pedal applied regen gives more power, when accelerator pedal released regen power depends on the speed of the car, when I drive with speed 40km/h in D mode and leave accelerator pedal I get ~ 5kw regen, when on same speed I choice B mode I get ~ 8kw regen if I remember correctly, maximum regen that I seen with brake pedal pressed is 29-30kw both in D mode and B mode.
Regen alone will not give maximum MPG, coasting when that possible gives, more gentle braking for extended time will waste less energy on conversion and more safe for battery, battery not heating up too much.
There another technique  to save more gas, I seen one YouTuber Chanel I think from Taiwan, he tailgating lorries, using ACC on  FIT e:HEV