[Cloud9...68]

The discussion about foam pads on the underside of the hood and the impact on engine bay temperatures got me to wondering about the pros and cons (of there are any) of thermal exhaust wraps. Seems like they would be a good way to reduce the temperature in the engine bay, particularly with the vulnerable hall sender and heater control valve nearby. One obvious issue I can think of is the fact that you have to have the exhaust off to wrap it, but that isn't a problem for me at the moment. Thoughts?

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[RMW]

while not cheaper ceramic coatings have worked well and you don't have the smell in the car like you will with the wrap

inside and out ceramic coatings should reduce your temps by 50%

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[RS Barn]

Exhaust wrap bad in long term.

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[flash]

i had it on my car for a while, and have used it successfully on others



while effective, exhaust wrap causes pipes to deteriorate faster. this is largely due to the inability to get a truly even wrap all over. even a difference of 1/4" of wrap spacing and you get hot or cold spots. this causes the pipes to expand and contract unevenly, causing cracks.



i concur that ceramic coating is better. it is not allowed in some classes of racing though.



mine is coated inside and out

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[Cloud9...68]

Interesting - the wrap seemed like a no-brainer, but clearly there are problems with it I wouldn't have thought of. Thanks for the replies - this forum really is awesome.



Out of curiosity, why would ceramic coating be banned in some racing classes? Does it really provide that much of an advantage?

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[flash]

it can make a difference, but it depends on a lot of other things too



an example of where it is not allowed is 944 spec in NASA, yet wrapping is allowed

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[RMW]

wrapping good stainless steel isn't so much an issue..........however wrapping mild steel will have rust in your manifold very quickly. Wait til you get rain on it, it will rust that baby so fast it will make your head spin.

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[Cloud9...68]

"i concur that ceramic coating is better. it is not allowed in some classes of racing though."



I was thumbing through my October edition of Grassroots Motorsports, and ran across an ad for a company (Swain Tech Coatings) that specializes in ceramic coating of a variety of engine parts, including pistons, combustion chambers, exhaust posts, headers, etc. This reminded me that Craig Woodman had this done to his engine to provide some additional cooling in the hot Australian climate. Since I have my engine apart, and live in an area about as hot as Craig's, I got interested in looking into possibly doing this to my engine while I have it apart. But then I found this in NASA's CC&R's:





18.6 Engine Paint And Coatings

Engine painting is allowed, provided that it is applied to external parts only. No painting

or coatings to any internal drive train parts, manifolds, etc. is allowed, unless specifically

allowed by class rules.



Argh!! Another potentially beneficial mod bites the dust. I understand the logic behind discouraging people from being able to do things that require disassembly of their engines (to keep costs down), but at least in principle, the concept of shielding the base metal in the cylinder head and pistons from the heat of combustion seems to be an attractive thing to do from an engine longevity standpoint. This is about the fifth thing I've been interested in doing to my car that I can't if I ever want to eventually race it. Oh, well, these are the trade-offs, I guess.



It seems that in an ideal (and independently wealthy) world, one would need two track cars, one to race, sticking to all the rules, and another all-out, no-holds barred weapon for HPDEs. In my case, I live so near a track that I can use anytime I want, even during the week, that having a top-notch "HPDE" type car is something I'd get a lot more use out of than a competitive race car, and for less overall cost. But on the other hand, reading the stories of all the successes of our 968 racers really gets my juices flowing, too. Decisions, decisions...

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[tamathumper]

Wouldn't coating the inside of the exhaust reduce the diameter and limit throughput - thereby making it a possibly *bad* thing to do for racing? Or is the coating so thin as to be immaterial?

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[flash]

the coating is very thin. any diametrical reduction is more than made up by the improved flow.

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[Cloud9...68]

I guess I'm struggling with why something like ceramic coatings are illegal. As long as the car meets the power-to-weight ratio rules of the particular class, why should it matter how you get there? What am I missing?



I realize this is something that would have next to zero chance of getting caught, but I'm a ridiculously honest person, and my conscience wouldn't allow me to so blatantly violate a rule like this.

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[flash]

it's illegal because it really helps.



rules in production class racing are there to keep the field even, and take the budget out of the equation as much as possible, making the racing more about the driver and less about the car. this is exactly why i stopped running in those classes, and will only go back in either super-modified, where it's as much about the car as the driver, or maybe formula

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[Cloud9...68]

Yes, I understand the reasoning, and it makes sense to an extent. But I really struggle with its application to something like internal ceramic coating, because 1) Any horsepower impact it has could be easily be negated by assessing a weight penalty, and 2) Since it can lower the operating temperature of the base metals of the engine, it could potentially increase the life of the engine, thus potentially reducing cost in the long run. My gripe is that I have my engine apart, making it an opportune time to take advantage of something like this, especially in a climate as hot as mine, so I cringe at the thought of putting it back together without doing everything I can to protect it from the rigors of track driving while I have the chance. I know, I know - take it up with the sanctioning bodies...

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[flash]

bump up a class and stop worrying about it.



that or change the exhaust for the races that have the issue, and leave it on there for DE stuff. it takes about an hour to change out the whole kit and kaboodle.

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[nissanite]

Sorry to say this to all of you law biding citizens but Swain makes a coating that is not detectable. cost more but....

If you feel guilty, shift 200 RPMS early.

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[flash]

lol. ok now everybody go tell the stewards he's cheating and make him tear down his motor.



i hate those silly rules. the coating is less than $200. who cares? by definition racing isn't cheap, and if somebody wants to be competitive and is getting beaten by a guy with coating, then go and get the coating. this is one of the rules that makes no sense to me.

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[94SilverCab]

I'm pretty sure that Ben and Crespo could beat me in Yugos if I was driving a GT3...it's still 90% driver ability...



Jay

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[Lear35A]

[quote name='flash' timestamp='1316059538' post='115457']

that or change the exhaust for the races that have the issue, and leave it on there for DE stuff. it takes about an hour to change out the whole kit and kaboodle.

[/quote]



But then it's $40.00+ for those stupid "O" gaskets every time.

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[flash]

lol - true enough - i've definitely bought my share of those.

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[Cloud9...68]

" this is one of the rules that makes no sense to me. "



I couldn't agree more. I would do it purely to help cool the base metals in the engine down a bit. I have no interest in making my car faster than other peoples'; this is amateur racing, after all. If I won a race knowing it was because I did something to give my car a slight edge, it would make it a hollow victory.



As far as those "o" gaskets used for the exhaust manifold - dumb question, but given that they're made of metal, do they really have to be replaced? Mine look brand new.

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