Contour Enthusiasts Group Archives Forums Modifications Duratec Performance Ceramic type coating for heatshield / UIM

Heat shields work a little for convection types of heat from the hot air, or rather to block airflow like around a cold air intake so the incoming air has less contact with hot air, but mainly they are for radiant heat sources.

I'll say it again plainly, heat shields are for radiant heat sources.

Heat shields used to block hot air are just that, air dams and are not really blocking heat out, just airflow.
Coatings are for conductive heat. That is say heat conducted through metal or plastic parts. The problem is that the coating has to be between the heat source and the heat sink.
With the parts connected the way they are in an engine, more heat will be conducted through the bolts and gaskets into your intake manifold than will radiate onto the intake manifold unless as on some engines the intake and exhaust manifolds are co-located. Some old honda engines had the intake and exhaust enter right next to each other and in that case a heat shield was required to stop RADIANT heat.
So what am I saying? You are wasting your money if you are putting specialized coatings on heat sheilds between the upper and lower manifold and on most other heat shield applications.

The only place I could see a practical use of coatings is on the inside of your intake pipes and manifold runners. The barrier would be in place between the medium that you are trying to isolate and the heat source.
If you put it on the outside of your pipes then all you are doing is slowing heat transfer from the convection currents of air, which is a pretty poor heat transfer method when compared with conduction anyway. All that means is that in the case of an engine in an engine compartment, heat will travel through the connections, bolts and clamps so much faster than it ever will through air conduction so you aren't doing jack-sh|t to stop it. The air temp will never be hotter than the actual engine temp since the engine and radiator (via coolant from the engine) are what actually heat the damned air!

In a perfect setup you would have the thermal coating completely coating the inside of your intake air path so that the air touched nothing (or nearly nothing) but your thermal barrier until it entered the combustion chamber. This would reduce the conduction of heat into the air from the hot intake pipe. From there the exhaust piping would have the coating on the inside to retain heat in the exhaust rather than into the piping and then radiate onto components outside.
Now using thermal coatings on the outside of very high heat objects like exhaust components will help reduce radiant heat and convective heat transfer from the exhaust pipes to the surrounding components, so that isn't a complete waste. An uncoated heat shield between the exhaust and items you are trying to protect is a much better method than a coating though since we really want to cool the exhaust piping with airflow and NOT let the radiant heat hit other surrounding components. The coating would slow the cooling of the exhaust pipes to the air around it and is a double edged sword.

However, you are not going to keep any of the intake or exhaust piping from heating up!!!!! The piping will still conduct heat from the combustion chamber to every single part that is bolted, clamped, glued or stuck to the engine. Those parts gain more heat through contact than they ever do through hot air flowing through the engine compartment.

Therefore, any money you spend on coatings for anything besides the INSIDE or your intake, combustion chamber, or inside and out of exhaust pipes is probably a waste of money and will not change the heat levels in the components in a measurable fashion.