Cam design limitations

Stroker - Take a basic infra-red temp gage and try your theory... I have. That was where the examples came from (ok, given, it was out of my memory). My middle school classes taught that heat expands, cold contracts just as your "hot molecule bigger" statement. Must be different schools...lol The basic hot larger is right. But the speed bit as a result of "bigger molecules thru the same size hole means faster" is dead wrong when referring to hot gas flow. As soon as the burn is done heat creation stops. Simple physics. Without a heat energy source, heat is dissipated. It's the same thing with areas of the chamber. If you have "fire" in the manifolding, you have a huge problem. You do realize what an EGR system does, and why, right? They are currently used in every production gasoline engine. It's called and Exhaust Gas Recirculation system. It uses exhaust gases, directly out of the exh port, to COOL the intake charge and chamber. It reduces the oxides of nitrogen and helps keep the engine out of detonation and ping.

On the collector, the collector length has to do with exh pulses and wave tuning, or series of exh valves opening and closing. Nothing to do with exh heat or creating a restriction. A tuned collector uses the frequency and inertia of exhaust pulses to help evacuate the cylinder better. Nothing to do with heat. The paint burning is what you do to find the best area for an X or H pipe connection.

But what do I know.