I know that it's supposed to insulate them. However, I started thinking...intake air temps are better when cooler, but why does it matter for header temps? The air has already left the engine itself, so the oxygen content shouldn't matter. Is there something wrong with my train of thought?

 

I think it's more of a case of keeping the heat out of the engine bay, not keeping it IN the headers.

 

THere's actually 2 benefits, and one potential danger.

Benefits:
1) Keep heat out of engine bay/lower intake temps/water temps etc.
2) Keep heat IN exhaust flow - hot air moves faster than colder dense air, hence exhaust gases flow out more easily - lower backpressure - lower load bearing on engine - increase HP.

Danger:
1) Gets too damn hot, and your header cracks.

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BTW, i will take this opportunity to say again that backpressure on ALL engines is a bad thing. Unfortunately many ppl mix up backpressure with exhaust velocity etc, and get led to believe that NA engines need backpressure.

This debate is raging on ClubRsx - sheesh don't know why I bother reading that bbs sometimes

 

Actually premature header wear, where the header actually cracks is usually due to header "wraps" not header coatings. I've seen the header just fail like that, and a huge hole is cracked out of them. Some blame it on improper installation of the wraps - too tight or too loose. Regardless, the coatings have not caused failures.

I spoke with Chris over at Jet-Hot this past week, while my header is being coated and shipped back to me at the moment. If such a thing happens to the header, they will replace it. They do not see these failures like the wraps.

 

From what I understand, the problem with header wraps is that it traps moisture, and that's what causes the problem... since coatings don't trap moisture, you won't have that problem.

-Shing

[QUOTE]Originally posted by Schatten
[B]

Actually premature header wear, where the header actually cracks is usually due to header "wraps" not header coatings.

 

Thank you for that statement!! All car "nuts" should understand such concepts, but many people still talk about more backpressure being better, when it is actually the design of the exhaust keeping the gas velocity up with perhaps less turbulance and better "scavenging".

 

Thanks for the responses guys!

 

Yep the backpressure issue is getting on my nerves - and thankyou to Texan for backing me up over at clubrsx

Sorry if i misinformed about header cracking - true the damage I have heard about was in header wrap cases rather than coated. And if you can get it warrantied then go for it I say

 

Does anyone have any data, or an idea of how much the coating helps isolate the heat? The only header I've had that was "jet-hot'ed" didn't appear to make a difference.

 

Right, Prolene, otherwise we'd all think sticking potatoes up our tail pipes would be a postive performance modification.

2x6