Advanced Engineering Tech - Engine coolant temps vs HP vs MPG

Me and my bro were chillin hard tonight, tippin back a few Natty Ice's, and we started gettin all technical and shit. Long story short; what effect do higher/lower ECT's have on HP and gas mileage? Higher being the stock tstat, lower being a 160* tstat.

Todays engines are designed to run hotter and thus burn cleaner. Now from an HP aspect, I am sure that the higher temps are NOT HELPING.

Smokey Yunick of small block Chevy fame always insisted power was better with a higher coolant temp as long as there was sufficient margin for knock error. More thermally efficient. Less heat loss from the combustion chamber.

That said, have seen examples of dyno testing done where more power was produced with lower than the 90C/195F - 100C/212F typical factory temps.

That may have been due to more advance being possible and optimum advance could not be reached with factory ECT numbers.

Depends a lot too on how much of the engine heat, contributed to by the ECT, influences intake charge temp variations.

Yeah the hotter your engine block, the better (assuming you can support the heat). When the explosion occurs in the combustion chamber a lot of the energy is released as heat. If the engine is all ready hotter, less of that energy can be released as heat (or waste energy). Engines are usually only like 23%-25% thermally efficient or something like that.