[Jay S]

I have done a few different ceramic coatings on engine parts, there are a lot of different reasons you might want to run a ceramic coating. But I am not sure reducing detonation should be one of them. I can think of examples where piston coatings made a little less than a 10 hp increase in power on a 500+ hp engine. But I have seen arguments both ways for how it effects the engine. One school of thought says the piston runs cooler and is reflecting the temps back into the chamber. The other school of thought suggest by reflecting the heat the piston can not transfer as much heat, and it is raising the combustion temp, and can make preignition occur earlier. My guess is both those ideas are correct. Lol

I don’t know what they have in mind for a coating. I understand some thermal coatings disperse heat instead of reflecting it so the piston survives to make more power, others reflect to make more power. On a stockish engine, with a stock type piston I doubt the coatings would gain much of anything on detonation. For detonation my best guess is the dispersion would do more than reflection, I am guessing the ceramic type that they are looking at is the reflection.

I don’t think Ceramic coating the exhaust results in better thermal efficiency. More it effects the thermal efficiency from a change in the speed of the exhaust by effecting the temperatures. It is like putting a little longer tube header on your car. IRC, it is because the temp change effects the sonic number, the pulse the header excepts becomes longer.

We have worked on some cast piston engines that have had detonation to the point that we burnt the moly coating off the top compression ring. You could nearly pull the top ring off like a piece of baling wire, tension was gone. I know ring lands and rings can break too. But a lot of times I think it is from not quite enough ring end gap. The detonation produces excess heat, then bad stuff happens. Once the land or ring breaks and you still have detonation, everything gets worse fast. The combustion becomes a blow torch. IRC we have ran 23 lbs of boost with a cast piston, survive at least for the testing. If you have concerns about detonation I would gap the rings wider, use a cast type top ring, or ring design to take more heat than moly, and 45* valve instead of 30*s. Then add your piston coatings.