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Commute mpg


mr.tourette23

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8 hours ago, Menoporsche said:

.... with engine off...

That’s coasting mood for ya, I think that’s great. I do it manually in the wife’s car now, notch it into neutral if I’m going into town (downhill all the way).

Economy isn’t as important to some with a sports car of course, but it is a definite benefit when you can cruise from Kent to Wales at 40+ mpg and then aim for sub 20mpg on the interesting roads. No point wasting money on the motorway which is what most cars I’ve had would do.

At last year’s Dragons Throat run it saved me the cost of the airbnb and evening meal. That’s very worthwhile.

 

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6 hours ago, moospeed said:

That’s coasting mood for ya, I think that’s great. I do it manually in the wife’s car now, notch it into neutral if I’m going into town (downhill all the way).

Economy isn’t as important to some with a sports car of course, but it is a definite benefit when you can cruise from Kent to Wales at 40+ mpg and then aim for sub 20mpg on the interesting roads. No point wasting money on the motorway which is what most cars I’ve had would do.

At last year’s Dragons Throat run it saved me the cost of the airbnb and evening meal. That’s very worthwhile.

 

Notching neutral still leaves the engine running with idle fuel.  If you 'coast' with transmission engaged down a hill the fuel supply is off completely on most fuel injected cars.  Also being out of gear is not good practice.

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2 hours ago, ½cwt said:

Notching neutral still leaves the engine running with idle fuel.  If you 'coast' with transmission engaged down a hill the fuel supply is off completely on most fuel injected cars.  Also being out of gear is not good practice.

Hmmm that’s interesting, so the fuel is entirely cut on coasting in gear (in a manual) - so I could be using more fuel on my economy drive.

If that’s actually the case then why do Porsche do exactly that? There would be nothing to gain.

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2 hours ago, moospeed said:

Hmmm that’s interesting, so the fuel is entirely cut on coasting in gear (in a manual) - so I could be using more fuel on my economy drive.

If that’s actually the case then why do Porsche do exactly that? There would be nothing to gain.

All to do with engine friction. Coasting in gear down an incline will slow the car down quicker due to engine braking, then the amount of extra fuel to maintain or get it back up to speed would be more than fuelling tick-over whilst coasting. Like stop/start, it could possibly have saved enough fuel on test to drop the vehicle's CO2 emissions, tax band, and make the fictitious economy figures look better. 

I find the mode unnerving in autos, and if you do it in a manual you could be considered not to be in full control of the vehicle.

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4 hours ago, Codfanglers said:

All to do with engine friction. Coasting in gear down an incline will slow the car down quicker due to engine braking, then the amount of extra fuel to maintain or get it back up to speed would be more than fuelling tick-over whilst coasting. Like stop/start, it could possibly have saved enough fuel on test to drop the vehicle's CO2 emissions, tax band, and make the fictitious economy figures look better. 

I find the mode unnerving in autos, and if you do it in a manual you could be considered not to be in full control of the vehicle.

“Leave me alone, I know what I’m doing” - Kimi

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13 hours ago, GTSMarky said:

Blimey!

I recall a similar moment of disbelief when I posted on IWOC that I got 36.6mpg out of a UK spec Impreza 2000 Turbo in the late 90s on a long motorway run.

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