Author Topic: MPG for those interested  (Read 142649 times)

sportse

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MPG for those interested
« Reply #120 on: September 18, 2021, 09:49:18 AM »
I’m 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 I’m consistently getting lower/mid fifties. Compared to my Auris hybrid that did mid forties on the same roads.

It’s a very impressive engine/motor setup in the Jazz.

nowster

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Re: MPG for those interested
« Reply #121 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.

Kremmen

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Re: MPG for those interested
« Reply #122 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 ?

Let's be careful out there !

sportse

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Re: MPG for those interested
« Reply #123 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?

Kremmen

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Re: MPG for those interested
« Reply #124 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.
Let's be careful out there !

guest9814

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Re: MPG for those interested
« Reply #125 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.

Kremmen

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Re: MPG for those interested
« Reply #126 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.
Let's be careful out there !

guest9814

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Re: MPG for those interested
« Reply #127 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 ?

150234

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Re: MPG for those interested
« Reply #128 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.

John Ratsey

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Re: MPG for those interested
« Reply #129 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.
2022 HR-V Elegance, previously 2020 Jazz Crosstar

guest9814

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Re: MPG for those interested
« Reply #130 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

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%

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.

Kremmen

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Re: MPG for those interested
« Reply #131 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.

Let's be careful out there !

sportse

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Re: MPG for those interested
« Reply #132 on: September 23, 2021, 06:07:55 AM »
Yes, I’ve stopped looking at the instant mpg bar as it doesn’t 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.

sportse

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Re: MPG for those interested
« Reply #133 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 I’m sure mpg would be over 70.

Kremmen

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Re: MPG for those interested
« Reply #134 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.
Let's be careful out there !

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