Has anyone used Jet-Hot coating on their headers or on their cat-back exhaust. With engine compartment heat being such a negative, the 50% reduction in heat radiation from the exhaust system would seem desirable. Is there a problem with all of the retained internal header heat voiding the aftermarket header manufacturers warranty on the cat? There is also the benefit of a slight increase in horsepower due to the inproved flow velocity due to the internal temp increase. Any experience with or thoughts about this? Joe
Duck and cover my friend.
Hello dreis44, could you please tell me more about your concerns with Jet-Hot coating? Joe
Just one more observation, the factory OEM headers have thermal reflectors on the collector area and surrounding the cat! Joe
And the factory exhaust has thermal shielding back along the pipes before the 2nd cats. It isn't there for performance reasons it is there to try and keep heat away from the axle/wheel area. I suppose you could try this stuff, but how would you know if it made any difference? dyno your car before and after? temperature probes positioned all around the engine bay? I'm of the opinion that as long as the heat from the headers/exhaust isn't hurting anything (like melting a brake hose, etc.) then there isn't a reason to do it other than precautionary, not performance related.
I have no idea how well the Jet-Hot coating will reduce the heat radiated from the headers, but in theory at least, a shiny surface has much less emissivity than a black body.
Jet-Hot has been around for many years and I've never heard anything but good about the product. My Spyder headers are Jet-Hot coated and they have stayed shiny for the last 5 years. I did not measure engine compartment temps before and after the installation.
I have a friend that coats his snowmobile expansion chambers and swears by it, claiming lower underhood temps and performance gains - no formal dyno runs but increased fuel delivery under similar conditions (he's had to increase his fuel to keep exhaust temps down as scavenging is more effective)
With cars, the sensitivity is going to be different than a two stroke, of course, but there are reasonably creditable companies that have tested this with positive results. The thermodynamics alone would say you would keep underhood temps down as well as retain heat in the exhaust, but header temps go up also which could give thermal growth or fatigue concerns dependant on the application. As K-Man says, the exact benefits in these specific circumstances would be interesting to quantify and measure. Seek out the advice of one of the engine tuners on this topic would be my advice.
Not sure about Jet Hot. Personally I'd check into Swain Technology's ceramic thermal barrier coatings. HTH
