Ceramic exhaust coatings and exhaust wraps

obi_waynne

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Under bonnet temperatures are one of the biggest performance killers around. Quite simply, you want your engine to be sucking in cold air as this carries more oxygen and will allow you to burn more fuel. The exhaust system is one of the contributors to under bonnet temperatures. You can therefore lag the exhaust to help prevent this heat soak into the engine bay.

Continue reading... or post your comments below on this article.
 

obi_waynne

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It is surprising how much a ceramic coating can cut down underbonnet temps! There are other coatings around of course which will work almost as well and are probably cheaper.
 

old-git

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You will struggle to find a better coating that that supplied by Zircotec. Not cheap but the best never is. Do you want lower under bonnet temps or not?
 

TCJBOLDIE

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I have my exhaust manifold ceramic coated and when my T3 SP V band turbine housing arrives it will get coated as well.
 

obi_waynne

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The benefits are many according to what I've read. Lower intake temps, dropping 30 oC will give around 6% more power! Some coated exhausts reduce under bonnet temps by 50oC.

It aids cylinder scavenging & allows turbos to spool up more quickly (hotter gases flow faster)!
 

rodhotter

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i have had several name brand ceramic exhaust coating + NONE of them held up on a daily driver in snow + salt winters. problem is the cheap mild steel piping under the coating. wrapping pipes or other parts shortens their life for sure. unless racing for $$$ just get stainless steel, 304 grade stainless holds almost 3 times the heat in the pipe + will outlast your vehicle!!!
 

old-git

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i have had several name brand ceramic exhaust coating + NONE of them held up on a daily driver in snow + salt winters. problem is the cheap mild steel piping under the coating. wrapping pipes or other parts shortens their life for sure. unless racing for $$$ just get stainless steel, 304 grade stainless holds almost 3 times the heat in the pipe + will outlast your vehicle!!!

Have you used Zircotec ceramic coatings?

Wrapping pipes in a wet climate is probably not a good idea and the wrap traps the moisture. In dry climates there isn't a problem.

Where did you get the data that stainless steel holds almost three times the heat? What do you mean by that? Are you saying that compared to a mild steel exhaust emitting 900 degress C a Stainless pipe will only emit 300?

The emissivity coefficiant of polished steel is 0.07 and polished SS is 0.075 so the stainless emits slightly more than steel when both are new and polished.

Once weathered steel increases to 0.79 and SS to 0.85 so the stainless still has a higher emissivity coefficient, so I can't see where you get the '3 times' from.
 

MikeMcCarthy

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JMHO I never saw a heat reduction when I had my headers ceramic coated , pic,

When I wrapped my next set of headers I could actually put my hands on the pipes, so if I wanted to reduce engine compartment temps and put more hot air through your turbo I would highly recommend the wrap. I have heard people sat wrap cracks or rusts out headers , I recently unwrapped a set of headers I bought new in 1989 and sanded them down and repainted them so a friend could use them , still looked great .
 

old-git

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What coating did you use Mike? My manifold and exhaust were coated by Zircotec, who also coat F1 exhausts.

I have been considering wrapping the exhaust as well. Zircotec don't recommend doing this but couldn't give me a reason. I don't think they have been asked the question before or done any testing.

Wrap works well if done properly and kept dry.
 

MikeMcCarthy

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I used " JET HOT " on mine . Where the pipes came out of the exhaust ports it dulled out to a flat grey color and all of the ceramic coating came off the inside of the pipes. I blamed the coating coming off on the inside of the headers on the high heat from my turbo. I believe that the only damage wrapping headers that are ceramic coated will be the discoloration of the ceramic coating in the wrapped areas . Mike McCarthy
 

rodhotter

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i had jet hot + HPC coated pipes with little longevity, this is a daily driven car, snow, salt, + simple rain, coating peeled in a few years!! 304 stainless on my 2001 jetta-bora 10 years, dull but NO deterioration at trade in time. just search stainless steel, there are many with different properties + $$$$
 

MikeMcCarthy

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Stainless is nice , and expensive too . I usually use about 75 ft to wrap my headers for around a US Dollar per ft. I overlap more than most do , soak in water before installation and stretch it tight , when you start it up the engine first time the water cooks off and tightens the wrap even more. DEI makes a spray coating to protect the wrap but I have not used it , my car is no show car so function/cost is the priority .
 

old-git

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I used " JET HOT " on mine . Where the pipes came out of the exhaust ports it dulled out to a flat grey color and all of the ceramic coating came off the inside of the pipes. I blamed the coating coming off on the inside of the headers on the high heat from my turbo. I believe that the only damage wrapping headers that are ceramic coated will be the discoloration of the ceramic coating in the wrapped areas . Mike McCarthy

Hmmm. If the coating came off due to turbo heat then I would suggest that they didn't do a very good job. Ceramic coatings are specifically designed to deal with turbo temps, well they are over here in the UK.

My stainless steel exhaust is coated in a matt black so I doubt that I will experience much in the way of discolouration -)
 

SLEEPER

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I'm not sure exactly how worthwhile zircon is on road cars but I do know it doesn't come off if done right.
 

obi_waynne

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Any coating is only as good as the surface it is bonded to. Old exhausts will not usually coat well unless they are very thoroughly cleaned up before the coating is applied. You also need a good even coating, which professionals will do anyway.
 

MikeMcCarthy

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The headers I had coated were brand new and were never run prior to being coated. They were mild steel tubing which was tig welded by Dave Kawell a well known VW engine builder. I was surprised by the coating coming off the inside of the pipes and they offered to redo them but I changed my engine combination and had another set built for it so I never pursued it.
 

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