just a basic question - will heat wrap make a difference in tempreture in the engine bay?
I know its to keep the heat in the exhaust/manifolds, but is there any noticable differences in the tempreture?

any opions welcomed

jon

There is a Night and Day difference.

quote Originally posted by jon m: just a basic question - will heat wrap make a difference in tempreture in the engine bay? I know its to keep the heat in the exhaust/manifolds, but is there any noticable differences in the tempreture? any opions welcomed jon

It's a night and day difference if you use enough of it, it has to go on kind of thick for good insulation. The downside is that if it is used on non stainless exhaust parts they are very likely going to rust at an accelerated rate if moisture is a problem in your area and letting the car sit for extended periods of time is common practice. You'll have to paint the exhaust to help prevent or slow the process. I made headers for my car that were not only painted with high temp paint first but also shielded from water some with a pre wrap of aluminum sheet metal and then the heat wrap applied over that. When I removed the headers for a redesigned exhaust system and unwrapped them they showed signs of severe flaking rust despite my efforts. I'm sure the much higher temps due to turbocharging and being heat wrapped along with sitting for months at a time while working to complete the swap contributed to this but non the less it's a tough balance to maintain as custom exhaust work is tedious and time consuming. I don't expect to have this problem with the new exhaust system comprised of cast iron manifolds and a stainless crossover which is highly unlikely to get wet and wouldn't have much of a problem if it did.

I would Never use that wrap again. I had it on my 82 TA 350 ZZZ . Yea it cooled the engine bay, But, it
rotted my 500.00 Headers.

Shannon

If you do use, soak it in water, then wrap it. It will give it a tighter fit.

quote Originally posted by njcwgrl: I would Never use that wrap again. I had it on my 82 TA 350 ZZZ . Yea it cooled the engine bay, But, it rotted my 500.00 Headers.

Somehow I don't think it was the heat wrap that was the problem. Mild steel will rust out. And even with stainless I would have them ceramic coated.

I wrapped my Vette side pipes and my Fiero 3800 exhaust from manifold to tips.
I used ceramic based heat paint on the pipes, then I soaked the wrap in water to get a better fit, then I coated the wrap with paint as well (after they dried). Have not had any issues so far. (Fiero was done about 8 years ago, Vette was about 1 year ago.)
Aluminized(sp?) pipes or stainless pipes are best to work with. The Vette has "Jet-Hot" coated manifolds and Aluminized side pipes, the 3800 has stock manifolds with the process above and mild steel pipes.
If the wrap is sealed, it should last a long time even on mild steel pipes.

-Dave

[This message has been edited by IFLYR22 (edited 07-22-2010).]

I just wrapped the exhaust for my 3800sc so I haven't tried it out yet. I used the ceramic paint before the wrap and then wrapped it with the DEI Titanium wrap. It doesn't require wetting and is supposed to be good for 1800F. I also made sure to get the paint above 400F... Wife wouldn't let me use the oven...

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-Brian

My 87 GT Poly Suspension Upgrade (all pics) thread
Removing the roof panel

I did use the oven shshshsh...........

If you use header wrap and overlap it the change in radiant heat is pretty good. The stainless stock pipes won't rust either.

I just finished my long tube headers in mild steel, had them ceramic coated, and then I wrapped them. I used VHT high temp ceramic paint for the collectors, and baked them as per the instructions. I also used ceramic paint on a couple of elbows and stuff close to the headers.

The actual surface heat difference is negligible. It is the radiant heat that is the major difference.

I find that mild steel headers of all types, if not ceramic coated, flake and rust at an alarming rate. It is because the heat is so high with headers. Shields do help. I also try to keep wiring at least a few inches from heat sources.

Hope this helps.

Arn