a technical discussion, engine efficiency Options

[r_towle]

so, I have been thinking (not always a good thing)
If an engine is basically an air pump, and the objective is to make it as close to 100 percent efficient, why is the exhaust valve so much smaller than the intake valve?

Forget emmisions, forget fuel delivery, just want to understand why this is so...it is so on most engines...

Rich

[Mueller]

QUOTE (Al Meredith @ Aug 18 2005, 07:07 PM)

I have read some on engine basics (no reguard to number of cylinders , configuration ETC) and the intake to exhaust ratio is +/- 75%. Try this on just about any stock engine and I think you will find its close. I also read that the theoreticle (spelling) limit for a 4 cylinder inline is 2.2 Liters. The pistons get to big and get "buzzy" at high rpm. Once again, think about it , how many four cylinder engines are bigger than 2.2 L ? Some are but they use balancing shafts.

that has to be BS with regards to engine size and cylinder number......a chevy V8 350 cubic in motor has pistons the same size as a /4 motor

with that theroy, no V8s would be bigger than 4.4liter and the Chevy V8 has models up 454 cubic inches (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif)

plenty of inline 4 motors with 2.4, 2.5 displacment and larger....