Exhaust Wrap

[Quint]

Just finished making a new dump pipe section for my 1G (finally sorted out the o2 sensor mounting point), The new length runs from back of both turbos to just behind the fire wall where it then joins the exhaust.

With the new dump pipe i'm wanting to wrap it to keep the heat inside the exhaust as my understanding is, if you keep the exhaust gasses hot, they will flow quickly, if they cool they begin to expand and lose velocity. Is this the case?

Will wrap hold together this close to the turbos? (directly off the compressor/wastegate) and is it worth doing it?

EDIT: Also, what type of wrap would work best? I'm fairly sure the absetos (sp) would work while fibre glass wrap would fall to pieces. $ per m anyone?

[jakesae101]

heat wrap isnt advised as it can cause cracking in the pipes and welds

[strx7]

heat wrap isnt advised as it can cause cracking in the pipes and welds

I heard that a few times too, didn't stop me wrapping the manifold on my 5SGTE.

I suspect it is possibly true for those thin el cheapo stainless manifolds but for downpipes I cant see it being an issue unless its sh1tily put togther to start with. I have always heat wrapped the downpipes on my competition cars and never had any issues

[Dell'Orto]

Eventually it can cause thermal fatigue, but would be some time before it caused an issue.

[pc]

I've always had the headers on my corolla wrapped. I redid the wrapping recently because enough things had hit it to tear it up along the bottom, and there was a crack on the headers up near the head... it's possible that it cracked while it was hot and something hit the bottom of the headers. I also had to bend the headers forward again as they were getting closer to the sump.

I recommend wrapping, it should produce more power if the theory is correct, and reduces the heat soak into everything else in the engine bay... and the added bonus of being able to work around them while hot without risking burning your hands badly.

[QikStarlie]

hot gas takes up more area.

[cat007]

What type of metal is it?

If its stem pipe then wrap that baby up and forget about it cracking

[MAGN1T]

Eventually it can cause thermal fatigue, but would be some time before it caused an issue.

Here's thermal fatigue.

http://www.3si.org/forum/f1/my-epic-fail-pics-474306/

Steve

[sergei]

Eventually it can cause thermal fatigue, but would be some time before it caused an issue.

Here's thermal fatigue.

http://www.3si.org/forum/f1/my-epic-fail-pics-474306/

Steve

I am glad toyspeed does not allow large pictures in signature. So difficult to differentiate content from spam.

[tsoob]

i have mine wrapped all the way its mostly due to engine temp's getting out of controll without it.

I Say wrap up (or use the back door )

Check out the thread on my car in the projects section for photos etc.

[Dell'Orto]

Eventually it can cause thermal fatigue, but would be some time before it caused an issue.

Here's thermal fatigue.

http://www.3si.org/forum/f1/my-epic-fail-pics-474306/

Steve

No surely thats a BHG

[Crampy]

Eventually it can cause thermal fatigue, but would be some time before it caused an issue.

Here's thermal fatigue.

http://www.3si.org/forum/f1/my-epic-fail-pics-474306/

Steve

No surely thats a BHG

Oh no you didn't!

[MAGN1T]

No, broken ringlands caused by detonation, the blown headgasket comes next.

Steve

[escortman]

i thought heat wrapping steampipe manifolds was a big no no ? as they crack

[cat007]

i thought heat wrapping steampipe manifolds was a big no no ? as they crack

You're roughly, round about, something like, EXACTLY 100% wrong

Reverse that statement and you'd be spot on

You're thinking of stainless....

[escortman]

ook hmm i think brendan ih8tec told me that i must of misheard

[Crampy]

ook hmm i think brendan ih8tec told me that i must of misheard

Yep, you are right Matt.
Brendons manifold did crack. He now has it HPC or Procoated.
Steam pipe can still crack, but will handle it better than those $hit stainless manifolds you see on Tardme.

[MAGN1T]

The ONLY exhaust manifolds that don't crack are the factory cast ones. Stainless ones are best if you design them right so that they have room to expand and bend without cracking. Steam pipe will eventually break too and if they don't break then the flange will warp and leak. Leaking flanges aren't good.
Stainless is really the best material to use apart from cast as you won't end up with bits flaking off the inside and destroying a turbine.

Steve

[steve murch]

as Steve has said cast works best for long term but still cracks due to heat cycling and thermal damage.
stainless isn't the be all to end all,it cools off to fast and on a turbo car heat makes for faster exhaust velocity making for better response thus heat wrapping does help,down side there prone to cracking from welding due to not purging or wrong grade of stainless.
unsupported manifolds or long runners contribute to the cracking.
its pretty hard to go past a well constructed steam pipe/weld bend manifold, the only down fall is if your going to run a leaded fuel they must be coated inside to prevent rusting that damages the turbine wheel.
on an all out race car that doesn't see road use or long duration Ive used wrapped stainless exhaust tubing,its a race car who cares its not on there long enough to worry about it.
wrapping or not wrapping,nothing lasts forever.

[Mr Revhead]

Leaking flanges aren't good.

I think that's the first correct thing you have said on here.