Originally Posted by Stu @ M Developments
Remember that in this thread we are talking about the difference between 20deg C and 100+... not nominal 20 - 40s. As the intake air gets hotter we have to lean off to maintain acceptable AFR. This is a fact, and one that the speed density and Mass systems both take into account and utilise accordingly and correctly, which takes me right back to my first point.....
Well, the difference in intake temperatures can affect the egts, which in it's own right affect the likleyhood of knock.
A cooler charge unaccounted for can create a lean or even worse a stoich mixture, raising the egts which then raises the mixture temperature as the cylinder conditions would have directly changed. There is too much of a complex cycle by cycle relationship here.
You are just directly correlating charge temps before it has reached the combustion chamber with the risk of knock. That assumption is the rule of thumb that is just not right.