John,
Did they really print that about
CHT?
I don't remember that max CHT
equates to anything useful although it may correlate very well to max internal
cylinder pressure (ICP), which is a bad thing. ...but it's also affected
by cylinder cooling, while EGT is (mostly) not. Max EGT would be stoichiometric
which is most efficient if your engine can take it. Usually slightly
rich of that (e.g. 50 dF ROP) is better power but also involves more pressure
before top dead center and is close to max ICP.
There's a really scary picture
you get early in the APS course which shows how the internal cylinder pressure
varies in relation to crank position when you are running at "best power".
A measurable amount of the combustion expansion is actually pushing backwards on
the crank until it comes over the top. Great for torsional
stress.
Colyn