Author Topic: MPG for those interested  (Read 1054 times)

John Ratsey

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MPG for those interested
« 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!

Jocko

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Re: MPG for those interested
« Reply #1 on: September 03, 2020, 07:15:30 PM »
You can have my crown. Great mpg.

John Ratsey

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Re: MPG for those interested
« Reply #2 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.


John Ratsey

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Re: MPG for those interested
« Reply #3 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.

Downsizer

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Re: MPG for those interested
« Reply #4 on: September 12, 2020, 05:02:17 PM »
I’ve been averaging 52 mpg in my Mk3 over 4 years of “defensive” 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 I’ll keep the Mk3 for 2 or 3 more years, but I’ll soon need to replace the original front tyres!

chicksee

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Re: MPG for those interested
« Reply #5 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.

John Ratsey

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Re: MPG for those interested
« Reply #6 on: September 12, 2020, 08:33:46 PM »
I’ve been averaging 52 mpg in my Mk3 over 4 years of “defensive” 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".

chicksee

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Re: MPG for those interested
« Reply #7 on: September 12, 2020, 11:21:21 PM »
Yes, mostly motorway driving with average speed between 60-70
Changed vehicle profile, thanks.
« Last Edit: September 12, 2020, 11:25:31 PM by chicksee »

andruec

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Re: MPG for those interested
« Reply #8 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.
« Last Edit: November 11, 2020, 03:21:17 PM by andruec »

John Ratsey

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Re: MPG for those interested
« Reply #9 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.

andruec

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Re: MPG for those interested
« Reply #10 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 :)

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