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      08-11-2011, 11:31 PM   #125
Erhan
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Drives: Cooper S
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Quote:
Originally Posted by bruce.augenstein@comcast. View Post
Wouldn't it be nice if the current M3 got 30 mpg if you babied it? On track, seven mpg is fine, but the miserable mileage is THE weak point of the current offering. Hell, owners of the the 3900 pound Camaro SS tell me they routinely get high twenties to 30 mpg running 75 mph or better out on the road.
I totally agree that current M3 is pretty weak in terms of mileage.. But would I trade the high revving V8 for a fuel efficient turbo engine? No, not really. I know, in various threads you have mentioned (and proved) that high revving engine is not all that critical. Ford/Corvette engines were your examples. Lower redline, but similar power at better economy.. But still, there is something special about high revving engines...

Quote:
Originally Posted by bruce.augenstein@comcast. View Post
I agree, mostly.

Just a nit, and it's not actually written in stone, but manufacturers typically run their turbo/supercharged offerings a bit richer than their normally aspirated models at wide open throttle in order to reduce peak combustion temps and ward off potential pinging or detonation. Result: More fuel used for a given power level at WOT.

In addition, supercharged cars require you to "feed the blower" as drag racers say, because the power required to run the supercharger is real power made by the engine that never makes it to the flywheel. Those ponies are just as hungry as the ones that make it to the wheels.
Thanks for the great info. I forgot about the supercharger taking power from the engine hence reducing mileage.

Sort of off topic, but why running rich reduces combustion temperatures?
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2011 MINI Cooper S
previous cars: E92 M3, Z4MC, Z4 Roadster, E36 328 Sedan