Heat Wrap: Which pipes are recommended?

[dropdfocus]

Looking at the possibility of heat wrapping my uppipe & downpipe but wanted to know if anyone had proven pros & cons on the matter?

I know that wrapping the headers isn't always the best & getting them ceramic coated is more suitable. Thanks for any input you guys can provide.

Also, DEI makes a kit to install a heat sock around the hot side of the turbo, has anyone seen this done & is it worth while as well?
http://www.designengineering.com/produc ... =sp&pid=31

[Buffman]

IMO i'd cermaic coat anything you can. Heat wrap on exhaust is just asking for corrosion issues on the pipe.

[93forestpearl]

Bah, I say thats hogwash if you drive the car a lot. Fiberglass wrap that is not sprayed with the silicone sealer lets out any moisture. If you drive the car daily, its not really an issue.

Silicone treated wrap won't let the moisture out of the wrap as well and I can see an issue with that.


I have untreated wrap on my exhaust manifold and anything that gets on it, like coolant or oil, burns off rather quickly. On the otherhand, my buddy who used the treated wrap had oil from his build process weeping out of the wrap for quite a while.


Obviously, ceramic coating is ideal, but it usually doesn't come cheap, especially for quality work.

[Buffman]

Hogwash? corrosion just doesn't happen from moisture retention. The problem with wrap is that it holds in too much heat. When it does that it can heat the steel beyond the temperatures if's desgined to withstand. When that happens, the steel will break down. Like I've mentioned on other forums, do some reading about it

And before someone inserts the word stainless, Stainless steel does and can corrode.

[93forestpearl]

I understand what you are saying, and have heard it from many people. I took material science And its not necessarily oxidation of the metal, more like reverting back to a lesser state, like pig iron for instance.


At areas of high turbulance, such as right off the heads or in a collector, you are definately getting a lot of heat transfer to the piping. Heavy insulation can cause the metal to change phases and possibly cause certain elements of the alloy to precipitate out of it. I'm seeing this on my stainless downpipe, as it has some surface rust right on the bend after the turbo and it has sat for a month.

Smooth pipes with little bend or very smooth radii do not see nearly as much heat transfer, like the crossover pipe. The area of highest readable EGT's on the subaru manifold is actually in the collector where both sides come together. I've recorded over 200°
higher EGT's there, than right off the exhaust port. That area is heavy cast iron, and should not be that affected by high heat and/or heat retention. If it was, they would be making turbine housings out of something else.

Two years and about 40k (not nice) miles on my old exhaust manifold and it is fine.

[dropdfocus]

Ok, I didn't mean to get people up in arms about the subject. Just wanted a little feed back; yea or ney.

[93forestpearl]

I wouldn't say we're up in arms about it, just a little debate.

[dropdfocus]

Ok, fair enough.