[zonker]

Originally Posted by Frank Lee

http://ecomodder.com/forum/showthrea...peed-1477.html

There seems to be a point of lower rpms at which engines don't get more efficient.

phew, now thats getting way up into that engine cavity in the search for better mpg.

i'll bet that at a certain point, the speed in which the combustion explosion propels the piston down it's bore has an ideal.

I'd guess that's probably related to why under-square motors (greater stroke than piston bore) are more efficient at lower rpms than over-square motors (larger bore than stroke).