Anyone done this or know of its benefits? I know coating the exhaust manafold of a piston engine is somewhat beneficial, but what about rotaries?

 

Ceramics are insulaters. RX-7's have a hollow double walled exhaust manifold to help dissipate heat and keep them from being damaged. Coating the outer wall with a ceramic would only make the manifold hotter on the inside. I don't see why that would be good.

 

yea, coating the inside would be good though. it can be done.

 

it keeps thermal energy up, keeps exhaust velocity up, good thing, but yes it does keep exhaust hotter than a sumenbitch
or thats what i was lead to believe

oh and hes talking about coating headers

 

i thought i read somewhere that having the exhaust keep it's heat inside is supposed to be a good thing. i can't remember if there was supposed to be a power gain related to it, but i do remember reading that it was good for overall combustion. i mean, isn't that the premise behind header and turbo wraps?

anybody know the truth on this????

 

ok, here is how it goes. exhaust coatiings/wraps keep in heat (energy) which keeps the exhaust gases flowing quicker. in turn this will scavenge more exhaust gas from the chamber giving you a cleaner mixture for the next combustion process. it also helps to keep heat out of the engine bay allowing the carb to run cooler (cooler air=bigger bang) and generally letting angine bay components last longer.

downsides. if it is a blanket or wrap then the heat is being contained on the outside wall of the metal. this will cause the metal to fatigue much quicker, especially with a rotary, and the header will crack and fail sooner. this is worse of course with a wrap or outside coating since they are more effecient then a blanket.

however, if you get the header coated inside and out, it is a double wall so it is more effecient and most of the heat is stopped on the inside so the header will last longer then it would bare. so this is a plus plus situation. improved performance and heat protection for the header and engine bay.

 

That was my understanding, too. Performance gains are small, but it helps keep the underhood temps down and extends the life of your headers/exhaust manafold. jet-hot has a service that can do it, really good, from what I understand. Not sure how much, but when I (eventually) get an exhaust setup, I'll probably get my headers coated. thx

 

Is there any other place besides JET-HOT that does this?

I know it's a great product, hands down.

Unfortunately, all I have heard from them is that they take too long (weeks), charge too much (several hundred), and sometimes crack your manifolds with crappy shipping, - which we (the consumer) pays for both ways (to and from).

 

Anyone know of a place that does Ceramic Coating?

Inside as well?

I made up a custom header for my project car, and after all that work, i'd like to make them last longer. I also have to control the heat. So keeping them cool isn't an option.

 

Well, jet-hot does offer a warranty/guarantee, so if they cracked during shipping, I'm sure they'd reimburse you. I don't know how much it costs, though.
RacingBeat sells header kits you can weld together yourself for around $80. Stainless 309 and mandrel bent. So, if you can weld, that's a good deal.
BTW, ordering direct from RB is a bit cheaper than mazdatrix.

http://www.jet-hot.com/faq.html