Originally Posted by
Lead Balloon
Given the choice of a 74% power setting with a CHT of X and a 74% power setting with CHT less than X, I choose the latter.
Detonation is not the only thing that is detrimental to engine longevity. So is heat. The manufacturers say so.
We all know too much heat is detrimental to the engine. However, we are talking about a heat engine here so the thermodynamic efficiency increases with temperature. If the materials could take it we would run them hotter. It is always a compromise. It is too simplistic to say that colder is better. You could run at rich best power and get the same CHT as if leaned to BSFC but more power and a cooler exhaust valve. There are no free lunches.