As far as I know about heat wrap is it makes greater chance on breaking the exhaust manifold? Is this right. And is it recommended in turbochargers to coat the exhaust manifold from inside and out?

 

Heat wrap keeps heat in the pipes to help keep the engine bay temps down. And help with other surrounding elements form getting to hot or burnt.

 

Its suposed to be used to keep the pipes hot to increase exaust velocity which = Power. Its a old N/A trick and it works just as good on Boosted cars.

 

ya the heat wrap supposedly makes the manifold more likely to crack. i dont know if its something about moisture and faster corrosion or what. i am not sure if its totaly true or not. but it REALLY helps the heat, a LOT. i tried ceramic coatings on the manifolds and turbine housings on my Z - it did not noticably change anything. but i wrapped it this year, and it makes a huge difference, and i mean huge.

i used stainless zip ties to secure it. i highly recommend it to reduce engine bay temps and reduce risks of melting or damaging parts that may accidently contact the manifold.

BTW for those of you who decide to do this, do not be surprised by the smoke and burning smell!! it was terrible for a couple hundred miles and any time i got them really hot for a few days. just do me a favor and verify that its ONLY your heat wrap that is smoking!

 

Phunk, is that Heat Shield Products 2000F inferno wrap? Very good stuff, and the SS bands are super convenient and secure. We carry this stuff if anyone needs it. I tooo, am a little concerned about cracking with hot FI applications, so we usually use the wrap to protect wiring harnesses, hoses, and other things.

 

http://www.centuryperformance.com/heatwraps.asp

very good article

 

phunk, what brand coating did you use?

that is an interesting article, but it seems like the guy writing it took to extreme of a stance about header wraps (considering the name of the article starts with "Why header wraps suck..."). I too am concerned with cracking a stainless manifold...a cast iron manifold I wouldn't be quite so concerned, but still it would bug me a little bit.

 

I wrapped my APS 3.5 downpipes, the engine dyno encouraged me to do this after seeing them glowing orange after only a short period at 15psi!

 

yeah, he did seem a bit biased against them, but heck, if NASCAR scrapped them because a good thermal coating is better, they may be onto something. plus he did make some valid point and some that i have seen first hand (peeling off heat wrap and having the header crumble in your hands)

 

I think if the wrapping was kept minimal and away from welds, that would help on the cracking issue ---- Maybe ????

BTW ---That 2000F does look like it would do the job

 

I had all my hot parts ( manifolds, turbo exhaust housing, down pipes) jet hot coated and I must say it is amazing ! After running the car within 3 or 4 minutes of having it off you can actually touch the manifolds with your bare hand and not burn.

 

The wrap i used was called "longacre" i believe. I think I just ordered it from racerpartswholesale.com.

That article is interesting.

I have used the ceramic a couple times, my main reason for doing it was to eliminate the rusty look on cast iron parts. It may reduce temps like their charts say, but to my naked flesh I could tell no noticable difference. The wrap i put on my Z made a large difference, and it also has made huge differences in several other cars I used it in before my Z. So I guess the wrap speeds up the process of the part failing.. oh well.. it sure works better compared to the coatings as far as i can tell. or at least in my head.

 

To my knowledge, HS Products is the only company that gives a 2000F CONTINUOUS heat rating. Most others are about 1300F continuous, with peaks of xxxx. Good stuff though.

 

In my experience there are a few things to keep in mind with heat wraps.

1) You can put on to much. Pay attention to the directions, too much heat will turn your headers into iron crumbs.

2) Tune is more important, if your running lean or overly retarded, you will overheat the pipes (this can even be done to JetHot coated pipes) and cause the pipes to turn to iron crumbs.

3) They will be more brittle, so smacking the exhaust on speed bumps will turn the welds into iron crumbs.

I was running this on headers that took about an hour to install and cost $150 (and that was the expensive ones for the car). So with the Z expensive headers and long install times, I would not bother on a street car.

Chris

 

If your running lean I think you have bigger things to worry about than your turbo manifolds .

 

the only prob i have heard is using them on thin steel headers (not quality ones), not s.s or cast manifolds.

 

Wraping the headers will cause it to become so hot that the steel starts to recrystalize. Going from a homogenous alloy to crystaline grain growth and carbide precipitates. Oxygen easily oxidizes the carbides and carbon from the exhaust side penetrates the steel only to form more oxidizable carbides.

The material loses toughness and becomes brittle.

The only way to deal with the problem is to keep the part cooler or use a material like nickle or inconel that is more resistant to heat.

Cast iron is actually more susceptible to intergranular corrosion and grain growth than stainless steel, but it may not become a noticable problem as quickly because its so much thicker than the tubing in stainless headers.

The wrap is a much better insulator than the jethot coatings but the jethot coatings make a good chemical barrier between the hot metal and the atmosphere or the free carbon and hydrogen in the exhaust.

Coatings are even more usefull when wraps are used.

 

The fact that actually makes complete sense to me is kinda disturbing...

<--Just finished a Material Science and Engineering course last semester

 

So in a nutshell you're saying it's not best to wrap?

 

ok, so wrapping is not good...as far as i can make out so far.......
i'll wrap the all the surrounding wires, ac lines or what ever wire looms near the hot side of the turbo / exhaust pipes.......at least the wires / ac lines stand a better chance of not melting from the tn st setup.....