10% Mileage increase... free...

[Robin-535im]

Normal gas mileage for me has been ~20 MPG in my 535 im.

A while back I tried driving really really easy to save gas, like 5-10% throttle as a max, accelerating slowly everywhere I went. Worked okay but it was too hard to drive like that in a 535 5-speed, seemed like a waste. I could push up to 23 MPG at a max but couldn't sustain it because of my heavy foot.

Bill R. posted something a few years back about accelerating up to speed at 90% throttle but I never got that to save any gas. UNTIL I learned the second half of the secret... coasting.

I still drive like a bat outta hell but only until I get up to speed. Then I put it in neutral and coast as long as I can. Works best when traffic is light or on the highway/freeway. I've been sustaining 22 MPG the past few tanks, and that is pulling HARD through the first few gears up to redline, like the M30 wants to be driven.

My guess is that it works because (put your statistics hat on) MPG is a one-sided distribution. You can't go below zero MPG but you can theoretically approach a very high MPG. If you spend a little time at, say, 5 MPG while you rocket up to speed, you can coast at, say, 100 MPG (idling while the car coasts) and get a higher average. Not a huge difference but 10% = $7 a fill up, something to put aside for the new clutch I'll need from all the extra shifting.

Haven't tried a tune up and air in the tires, that's next...

[Paul in NZ]

Bill R. posted something a few years back about accelerating up to speed at 90% throttle but I never got that to save any gas. UNTIL I learned the second half of the secret... coasting.

I still drive like a bat outta hell but only until I get up to speed. Then I put it in neutral and coast as long as I can.

so you coast until you slow down to say 45 mph then accllerate hard to 60 again???
overrun uses no gas at all,idling still uses plenty on an M30

[ryan roopnarine]

IIRC, coasting in neutral, much like driving with the engine off, is specifically made illegal in more places than one would think. glad you could save some money, though. i don't have the stones to try that in an automatic.

[Robin-535im]

so you coast until you slow down to say 45 mph then accllerate hard to 60 again???
overrun uses no gas at all,idling still uses plenty on an M30

Often in traffic you can rocket up to speed and coast and usually by the time you have to speed up again, the light has turned and you have to stop anyway.

Otherwise - as you surmised - I oscillate +/- 5 MPH around the speed limit. For a 45 MPH road I'll hurry up to 50 then coast down to 40 and repeat, though I try really hard not to be a jerk to people around me by being an obstacle.

Cool thing about flooring it off the line is that everyone else is so far behind that you have some room to coast before they catch up so you're not slowing down the people behind you.

Windows up, flat road, E34's roll pretty dang well.

[632 Regal]

flat peddling off the line takes a **** load of more fuel than say half throttle to do the same job...


wheres Bill R when ya need him?

Often in traffic you can rocket up to speed and coast and usually by the time you have to speed up again, the light has turned and you have to stop anyway.

Otherwise - as you surmised - I oscillate +/- 5 MPH around the speed limit. For a 45 MPH road I'll hurry up to 50 then coast down to 40 and repeat, though I try really hard not to be a jerk to people around me by being an obstacle.

Cool thing about flooring it off the line is that everyone else is so far behind that you have some room to coast before they catch up so you're not slowing down the people behind you.

Windows up, flat road, E34's roll pretty dang well.

[attack eagle]

correct, test 02 will show you instantaneous fuel consumption. you burn more coasting out of gear than you do in gear, about 1.7 liters per hour more on my m50, probably even more on an m30, since consumption in gear decelerating on most any fuel injected vehicle is damn near 0.0

[e34.535i.sport]

I agree with the theory because I do it myself on the motorway... I'll get up to 80mph fairly quickly (not necessarily WOT though!) and leave it in gear but let it slow to 70 or 65mph and then get back up to 80mph and continue. The computer does indicate an improvement but whether it's a true reflection is another thing! I mentioned this a while back and someone said I was tricking the computer somehow, I can't remember who right now though...

The car will use less petrol being left in gear with no throttle than in nuetral that's for sure... but it will slow quicker... Which is best... ???

[Ken35i]

IIRC, coasting in neutral, much like driving with the engine off, is specifically made illegal in more places than one would think. glad you could save some money, though. i don't have the stones to try that in an automatic.

I wonder how the **** a cop would know that you are coasting and if you were pulled over; what would be said?
"Do you know why I pulled you over?"
"No..."
"You were coasting."
DUN DUN DUUNNNN!!!
Luck you weren't coasting 5km/h over the limit otherwise you would have KILLED someone!!

And you're right there is a law somewhere in the US against your car moving out of gear. If any of that **** were introduced here, I'd do burn-outs outside parlament out of spite.

Sorry. Had to vent, stuff like this grinds my gears.

[attack eagle]

actually on city streets (the only damn place you should even be trying this, use cruise control on the freeway by god) throwing it in 5th at 40-55 shouldn't slow the car excessively.
it doesn't on mine, and mine is higher compression (10.5 or 11:1)

[e34.535i.sport]

actually on city streets (the only damn place you should even be trying this, use cruise control on the freeway by god) throwing it in 5th at 40-55 shouldn't slow the car excessively.
it doesn't on mine, and mine is higher compression (10.5 or 11:1)

Can I ask what you think makes this dangerous on a motorway? People might say because people won't know your slowing due to your brake lights not coming on, but only an idiot would do it with someone flying up behind them... Plus, whoever's travelling behind you is responsible for watching the road in front of them. I can't see any other danger aspects really if your vigilant while doing it.