90MPG - Is it really possible or was the computer wrong?

Volvo6 · Sep 11th, 2012, 14:34

The other day on a stretch of the M3 I realised that I was rather low on fuel and to make sure I made the next services which were in 20 miles I drove as economically as I thought possible, at about 56mph and after coming off pretty much rolled up to the pumps without touching the accelerator.

The trip computer claimed I had done 92.5mpg since I'd reset it at the start of the economy drive. The stretch of road was pretty much flat with some very gentle climbs and descents, for most of the time I sat in the inside lane with my foot applying just a few fractions of a pound of pressure on the pedal.

Car is a 2.0D with about 82K on it and had just had a service. Is it possible that it did actually do the claimed MPG or is the computer rather optimistic?

72dudes · Sep 11th, 2012, 16:39

Both really, although the computer is usually a few % optimistic.

Remember, if you re-set the computer as you were travelling along (especially as you were slowing to 56) the engine was aleady warm, there were no start/acceleration/stop cycles, and as you say the road was fairly flat.

In my 2.0D S40 it's possible to maintain speed with 99.9MPG showing on the instantaneous readout for short periods.

Still, an outstanding result that man!

nozmeister · Sep 11th, 2012, 17:02

don't see why not...if I zero the MPG reading I can get up to 70-80 if i 'feather' the accelerator for a few miles when it's flat...gettings a bit boring though!!

grin factor · Sep 11th, 2012, 19:56

I've done similar when trying an economy run, but not set it when already up to speed. The computer is optomistic, but just goes to show what you can achieve if you try.

7050man · Sep 12th, 2012, 08:31

Yes it's possible.

I've done this several times on M25 (of all places) from M1 round to Dartford.

You have to drive constantly and at about 50mph carefully monitoring instantaneous readout and adjusting throttle pressure to keep it on the 99mpg figure.

Also I regularly see an average of 80mpg if conditions are perfect and I mean over a coiple of days driving, not just one trip.

Sep 11th, 2012, 14:34	#1
Volvo6 Master Member Last Online: Apr 9th, 2024 18:10 Join Date: Dec 2010 Location: Winchester	90MPG - Is it really possible or was the computer wrong? The other day on a stretch of the M3 I realised that I was rather low on fuel and to make sure I made the next services which were in 20 miles I drove as economically as I thought possible, at about 56mph and after coming off pretty much rolled up to the pumps without touching the accelerator. The trip computer claimed I had done 92.5mpg since I'd reset it at the start of the economy drive. The stretch of road was pretty much flat with some very gentle climbs and descents, for most of the time I sat in the inside lane with my foot applying just a few fractions of a pound of pressure on the pedal. Car is a 2.0D with about 82K on it and had just had a service. Is it possible that it did actually do the claimed MPG or is the computer rather optimistic? __________________ 1971 1800E, 2019 XC40 D3

Sep 11th, 2012, 16:39	#2
72dudes Junior Member Last Online: Jul 5th, 2015 14:31 Join Date: Jun 2010 Location: Bury St Edmunds	Both really, although the computer is usually a few % optimistic. Remember, if you re-set the computer as you were travelling along (especially as you were slowing to 56) the engine was aleady warm, there were no start/acceleration/stop cycles, and as you say the road was fairly flat. In my 2.0D S40 it's possible to maintain speed with 99.9MPG showing on the instantaneous readout for short periods. Still, an outstanding result that man! __________________ 2007 S40 2.0D SE in Barents Blue Pearl 2006 Mercedes-Benz SLK350 in Tellurite Silver 2007 Mercedes-Benz A180 CDi Elegance SE in Horizon Blue

Sep 11th, 2012, 17:02	#3
nozmeister Member Last Online: Today 19:08 Join Date: Dec 2006 Location: Surrey	don't see why not...if I zero the MPG reading I can get up to 70-80 if i 'feather' the accelerator for a few miles when it's flat...gettings a bit boring though!!

Sep 11th, 2012, 19:56	#4
grin factor Senior Member Last Online: Feb 27th, 2015 20:35 Join Date: Dec 2011 Location: sunderland	I've done similar when trying an economy run, but not set it when already up to speed. The computer is optomistic, but just goes to show what you can achieve if you try.

Sep 12th, 2012, 08:31	#5
7050man Master Member Last Online: Jan 25th, 2019 17:19 Join Date: Feb 2006 Location: Kent	Yes it's possible. I've done this several times on M25 (of all places) from M1 round to Dartford. You have to drive constantly and at about 50mph carefully monitoring instantaneous readout and adjusting throttle pressure to keep it on the 99mpg figure. Also I regularly see an average of 80mpg if conditions are perfect and I mean over a coiple of days driving, not just one trip.

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