Rio96 said:
I dissagree. Detonation is a function of spark timing,
a/f, charge temp, VE,, detonation should be controlled
by the ecm.
Yes, spark timing is a contributor of detonation, but heat is as well. The less heat you have in the engine, the less chance you have of your fuel spontaneously igniting (detonation).
You say that charge temperature is a function of detonation. What do you think happens to the air when it enters the combustion chanber? It's gonna start pulling heat from the cylinder walls to match it's temperature with that of the engine. If your engine is running cool then there is less heat to be transferred from the chamber to the charge.
Rio96 said:
How do you know this?, IMO, the issue is whether the
piston rings are properly lubricated.
Yes, lubrication plays an important part of the wear process, but temperature does as well.
"The coefficient of friction between aluminum (pistons) and iron (block) is a function of temperature. As the material's temperature increases, the coefficient of friction between the materials decreases. There is a sharp inflection in the curve of this property between 170-180, where the friction will increase rapidly with temperatures below 170."
-Mechanics of Materials, 5th ed. Dr. Jack McCormac, et al
Rio96 said:
With a car that never gets fully warmed-up, maybe,
with the car warmed up, and in closed loop, don't think so.
The more heat you have inside the comustion chamber WITHOUT causing detonation gives you a more complete burn of the A/F mixture. Having a more complete burn gives you more power, better mileage, and fewer hydrocarbons (emissions).
This is why auto manufacturere have been steadily increasing engine temperatures in the last few years.
Riley