i just picked up the august issue of car craft and there is an interesting article on ceramic coatings. they used headers from dynomax(i think). they used the same headers in ceramic coating and black paint. the ceramic coating used was from jet-hot.they ran each pair headers on an engine dyno(the engine used was a 454 crate motor). they ran both pairs at idle and at 3200rpm. then they took the temp of each one why'll they were on the running engine. here are the results:

black paint:524 F (idle) and 533 F (3200)
jet-hot: 215 F (idle) and 265 F (3200)

on the first runs with the painted headers, the paint started to flake of. they said that the ceramic coating will not crack, even if you hit it with a hammer. it will also stay nice and shiney for a really long time.

i just figured that i would post this because everyone is always asking about ceramic coating, and if its worth the extra money. i deffinately think its worth the money.

 

Wow, that's a huge temp difference.

 

And it's a difference you can feel while doing plugs. After about 15 minutes with the hood open, I can touch the headers with my hands and not singe my skin right off. But in the process of doing the #7 plug, I accidentally rubbed against the uncoated pipe coming off the collector.... ouch.

I actually bounced an air ratchet off one of my header pipes on accident once, the coating has a mark on it, but it didn't penetrate the coating at all. Jet-Hot is awesome stuff.

 

i'm kinda confused now.. i'd heard before that you wanted the exhaust temp higher.? what kinda difference dose the exhaust temp really make anyway?

 

a lower exhaust temp will lower your "under the hood" temp

 

You do want the exhaust temps a little warm, for the cat to function properly. But you don't want the exhaust heat to escape the piping (headers too) as that just raises under hood temps, decreasing performance. And causes problems to things that might get burnt.

 

That was not the exhaust temps but the temps of the headers themselves after running the engine. Uncoated headers absorb that much more of that heat and its bolted right to your heads, the part you are trying to keep cool. If they would have taken actual exhaust gas temps at the tailpipes on those two runs the coated headers would probably start out having a higher exhaust gas temp since less is heat is being absorbed by the exhaust tubing.

 

I read this article with interest and decided to challenge Car Craft's article. I have a set of Jet-Hot coated Edelbrock TES on my '91 S10 Blazer. I used the exact same digital non contact thermometer as CC my results in a real world car (not an open air dyno mind you) were quite different. Averaging about 425*. Now, if any of you have the same type of thermometer and can test an F-body for an apples to apples test I'd love to hear the results. Plus if you look for the telltale red IR dot on their pic one tests the tube and the other is on the flange. I bet it makes a world of difference. The headers did cool down qiuckly after shut down to <200* in under 3 minutes but that may be true with uncoated headers. I'm going to test my Z with stock manifolds before I antie up for a coating that may be 200.00+ wasted that could go somewhere else. Some real world testing is in order before we spend our long green guys. Someone or some mag article shouldn't make our decisions for us. I put a ton of thought into every mod on my Z to justify them and it usually pays off. Some of us do have other places to spend hard earned cash rather than waste it on someones good idea.
One thing I can say for Jet-Hot is that the headers on my Blazer do look as good as they did 2 years ago when I installed them.

 

You do want the exhaust gases to stay hot. Why? Because hot air is less dense, and moves faster. The faster it moves outta the way, the easier it is for the engine to suck in more cool air.

Cool in - Hot out.

That's the formula.

By keeping the 'underhood' temp cooler, you are also keeping the engine cooler (IE, the intake, the heads, as well as the carb/TB and air cleaner). That helps keep the intake charge cooler, and more dense.

That's why the coating is so sought after. They used to use header wrap, but that's stuff's ugly. The coating is much "cooler" looking.

AJ

 

Wow that is a huge difference. When I finally decide to get headers, I'm definitely gonna get 'em coated now.

 

well we knew that it had to be a half because they quated reduces underhood temps up to 75% and they usually exaggerate by 25%