Hyper Mileing

[Sancho]

Originally Posted by Langod

Be aware that coasting in neutral with most modern automatic transmission cars will actually hurt your mileage. (I don't know if this is true with maunal transmissions too) A modern automatic -- when you are coasting with your foot off the gas, will drop into a mode where it only fires cylinders frequently enough to keep the engine spinning, but while in neutral, it actually uses more gas because it's at a full idle. You can see it on some car's computers -- my wife's Subaru Legacy shows the mpg meter max out at 99.9 mpg (which means it's probably higher) while coasting in gear as opposed to about 65mpg on the same hill/speed while in neutral.

Noticed my Maxima seems to get better mileage in gear also. (tough to tell for real -- no computer display).

I just do it to save more gas money for my '03 SVT Cobra -- has a supercharged V8 that I've gotten down to 2mpg whilst "driving spiritedly". (it normally gets about 18-20mpg around town, though)

This is somewhat more of an instance than the rule, many transmissions dont freewheel while in gear and the slipping is taken up hydraulically etc.

We must remember, maximum combustion efficency and maximum fuel economy are two drastically different things. Max economy, most older cars you want to sit at ~55mph as that was where the epa mileage test spends most of its time and thereby you could wieght the epa rated mileage in your favor. The new test Im not so sure as I haven't run one of those in a while...

Max efficency, wide open throttle baby