Author Topic: MPG for those interested  (Read 531 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 »

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