I'm going to ask this here cause the various board lurking I've done makes me think someone here will know ...

In reading this (a very good read BTW) ... I saw ...

"Then there are temperature variations due to the changing pressures and absorption from hot engine parts. These variations cause changes in the local sonic velocity."

I understand that different pressure and/or temperature can effect the sonic velocity, but IMO only until the engine has "warmed up" ...

At that point, wouldn't the sonic velocity become nearly constant? e.g. Isn't this an "equation of state" situation?

Or is the point that the temperature (aka pressure) is variable due to differing RPM's, So, there is no "constant" temperature ...

I know this is beyond "general tech", but lurking has shown some folks that have both "theory" and "real world" experience that might help me understand ...

 

interesting article.
If you enjoyed that, you'd also like to read the David Vizard book on porting small block chevy cylinder heads. Same stuff, but a bit more applicable to the SBC (rather than formula racing heads).

Your questions seem more like something a prof of mine would ask, so i'm holding out for a paycheck, or a grade, before I cough up my info

This picture I found was the best to illustrate what is what, as far as porting goes.

 

ya never know ... the Q might show up on a test

and yes, this pic does 'splain stuff ...