Benefit to coating headers?
Thread Starter
Pro
Joined: Jun 2006
Posts: 667
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From: Marysville WA
Benefit to coating headers?
I am looking at getting the Kooks headers and high flow cats. I am trying to decide if I want to get them coated or not. I understand the concept but I am not sure what the true benefits are. Any thoughts? Pros/cons?
Additionally, would there be any issues in bolting the headers/x pipe -high-flow cats with a Borla stinger system?
Additionally, would there be any issues in bolting the headers/x pipe -high-flow cats with a Borla stinger system?
Le Mans Master
Joined: Feb 2006
Posts: 5,762
Likes: 4
From: Chandler Arizona
In my opinion coating is an absolute necessity for mild steel headers (Melrose), but not needed for a 300 series stainless header (LG's, ARH, Kooks).
The coating keeps the mild steel from rusting, plus it keeps the heat in, increasing gas velocity, increasing power (slightly) and keeping the underhood temps down. The kicker is that 300 series stainless already is a darn good insulator as compared to mild steel plus it does not rust. So if you want to coat the Stainless headers, do it for the bling, nothing else.
I could not find the insulating properties (i.e. thermal conductivity) of any of the coatings, but even if it's very low like a ceramic, the problem is it's not very thick therefore doesn't help as much as people think. I have LG Stainless headers and they are not coated. They still look great and the underhood temps are not noticeably bad.
The coating keeps the mild steel from rusting, plus it keeps the heat in, increasing gas velocity, increasing power (slightly) and keeping the underhood temps down. The kicker is that 300 series stainless already is a darn good insulator as compared to mild steel plus it does not rust. So if you want to coat the Stainless headers, do it for the bling, nothing else.
I could not find the insulating properties (i.e. thermal conductivity) of any of the coatings, but even if it's very low like a ceramic, the problem is it's not very thick therefore doesn't help as much as people think. I have LG Stainless headers and they are not coated. They still look great and the underhood temps are not noticeably bad.
Le Mans Master
Joined: Dec 2002
Posts: 7,588
Likes: 6
From: Montreal Qc
I had my Kooks coated by Swaintech in SW NY. Very happy with the finish, looks and reduced temps. You can actually touch the exhaust with the car running....yes it's HOT, but not nearly as hot as raw metal! 
Le Mans Master
Joined: Mar 2002
Posts: 5,253
Likes: 50
From: Sandy Eggo Calif.
St. Jude Donor '06-'07-'08-'09-'10-'11-'12, '16
Jet-Hot:
"Because of its low emissivity and insulating effect, JET-HOT Sterling creates a thermal barrier to protect headers - inside and out - while reducing heat transfer into the engine compartment. But the good news goes beyond protecting headers from thermal fatigue. Plugs, wires, fan motors, water pumps and other heat-sensitive parts get a break, too, in a cooler environment. Plus, power normally increases and safety for racers improves with lower temperatures.
The graph shown to the left, developed independently by a major US automobile manufacturer, shows just how effectively JET-HOT Sterling beats heat. The company's engineering team was astounded by temperature reductions exceeding 300°F when JET-HOT Sterling was applied to standard exhaust components. Car Craft also took a cool breath, after measuring temperature reductions of over 60% on header surfaces following the application of JET-HOT.
JET-HOT Sterling will normally boost power when applied to headers for two reasons. First, the coating promotes denser, more potent fuel/air charges by insulating the engine bay from exhaust heat. At the same time, it accelerates the pulsed-vacuum effect on “tuned” headers, resulting in more effective scavenging of cylinders. The increased velocity of exhaust gases produced by higher exit inertia not only clears each cylinder more quickly; it also draws in the next fuel/air charge more efficiently.
JET-HOT increases the endurance limit (fatigue strength) of most alloys subjected to stress loads, such as vibration produced by an engine, after exposure to high temperatures. In addition, JET-HOT does not contribute to hydrogen embrittlement, a condition associated with chrome and other coatings in which microscopic cracking can lead to premature and sudden part failure."
"Because of its low emissivity and insulating effect, JET-HOT Sterling creates a thermal barrier to protect headers - inside and out - while reducing heat transfer into the engine compartment. But the good news goes beyond protecting headers from thermal fatigue. Plugs, wires, fan motors, water pumps and other heat-sensitive parts get a break, too, in a cooler environment. Plus, power normally increases and safety for racers improves with lower temperatures.
The graph shown to the left, developed independently by a major US automobile manufacturer, shows just how effectively JET-HOT Sterling beats heat. The company's engineering team was astounded by temperature reductions exceeding 300°F when JET-HOT Sterling was applied to standard exhaust components. Car Craft also took a cool breath, after measuring temperature reductions of over 60% on header surfaces following the application of JET-HOT.
JET-HOT Sterling will normally boost power when applied to headers for two reasons. First, the coating promotes denser, more potent fuel/air charges by insulating the engine bay from exhaust heat. At the same time, it accelerates the pulsed-vacuum effect on “tuned” headers, resulting in more effective scavenging of cylinders. The increased velocity of exhaust gases produced by higher exit inertia not only clears each cylinder more quickly; it also draws in the next fuel/air charge more efficiently.
JET-HOT increases the endurance limit (fatigue strength) of most alloys subjected to stress loads, such as vibration produced by an engine, after exposure to high temperatures. In addition, JET-HOT does not contribute to hydrogen embrittlement, a condition associated with chrome and other coatings in which microscopic cracking can lead to premature and sudden part failure."
Pro
Joined: Nov 2005
Posts: 704
Likes: 1
From: TORONTO
My American Racing headers are JetHot coated. I have no idea if it's better for SS as you will get strong arguments for both by all vendors and experts.
For the mild steel it seems to be widely accepted they should be coated.
If I was to buy my headers again I think I would get them coated. For they do not discolor and they still look exactly like the day I put them in. Very clean and new looking. However I don;t think it;s a bad look at all either, of the battleworn blue/yellow hues of uncoated SS.
For the mild steel it seems to be widely accepted they should be coated.
If I was to buy my headers again I think I would get them coated. For they do not discolor and they still look exactly like the day I put them in. Very clean and new looking. However I don;t think it;s a bad look at all either, of the battleworn blue/yellow hues of uncoated SS.
Team Owner
Joined: Aug 2003
Posts: 38,314
Likes: 35
In my opinion coating is an absolute necessity for mild steel headers (Melrose), but not needed for a 300 series stainless header (LG's, ARH, Kooks).
The coating keeps the mild steel from rusting, plus it keeps the heat in, increasing gas velocity, increasing power (slightly) and keeping the underhood temps down. The kicker is that 300 series stainless already is a darn good insulator as compared to mild steel plus it does not rust. So if you want to coat the Stainless headers, do it for the bling, nothing else.
I could not find the insulating properties (i.e. thermal conductivity) of any of the coatings, but even if it's very low like a ceramic, the problem is it's not very thick therefore doesn't help as much as people think. I have LG Stainless headers and they are not coated. They still look great and the underhood temps are not noticeably bad.
The coating keeps the mild steel from rusting, plus it keeps the heat in, increasing gas velocity, increasing power (slightly) and keeping the underhood temps down. The kicker is that 300 series stainless already is a darn good insulator as compared to mild steel plus it does not rust. So if you want to coat the Stainless headers, do it for the bling, nothing else.
I could not find the insulating properties (i.e. thermal conductivity) of any of the coatings, but even if it's very low like a ceramic, the problem is it's not very thick therefore doesn't help as much as people think. I have LG Stainless headers and they are not coated. They still look great and the underhood temps are not noticeably bad.
Also you might want to review this thread as it discusses a set of coated KOOKS headers.
http://forums.corvetteforum.com/show....php?t=1652323
I was going to have my LG Pros before I installed them and the vendor told me of a case where they had a heck of a time seperating the LG Pro headers from the rest of the system during removal of the system, presumably as a result of the coating.
If you do get them coated, he advises against coating the flanges.
http://forums.corvetteforum.com/show...15&postcount=4
Last edited by '06 Quicksilver Z06; Jun 16, 2007 at 10:07 AM.
