Originally Posted by Nixlimited

Nice writeup Mike.

Someone mentioned they thought heat was bad because their car ran better in cooler weather. The car runs better in cool weather because the engine produces power by the change in pressure caused by heating air in the combustion chamber (PV = nRT). Accordingly, if the air starts off colder at the intake (e.g. when it is cool outside) then the temperature delta after combustion can be greater and more power can be made. With that said, you want the combustion to be as hot as possible to create as much P as possible, but you have to keep material science in mind. Simply put, the metals used to make automobile engines can only take so much heat before they degrade and break. The waste heat is very useful for the turbos, as Mike mentioned. It's really just a matter of controlling the heat and making it do your bidding.