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Discussion Starter · #1 ·
I have a 2005 Subaru Impreza STI.
I recently purchased some 2", 50 ft length Thermo-Tec exhaust wrap.
I was planning on wrapping the downpipe to reduce under the engine temperatures (especially the intercooler).
However, I have enough tape to also insulate the headers.
Wrapping the headers and downpipe should reduce under the engine temperatures significantly however I was just wonderring if the slightly higher temeratures of the gases would be negative for the turbocharger or the catalytic converter?
My goal is to reduce under the hood temperatures making electrical components last longer, keep the intercooler cooler so overall I have more power. My concern though is by wrapping the headers the exhaust temperature may be hotter at the turbocharger to the point where it may be a negative. This I do not know. I know wrapping the downpipe is a positive as it will reduce temepratures under the hood and so what if the cat is a bit hotter or the rest of the exhaust. So i guess my main concern is the headers being wrapped and if this will affect the turbocharger?
Anyone who has experience with this please reply.
Tks!
 

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Discussion Starter · #3 ·
yes, stock headers, turbo. Will be installing cobb 3" downpipe.
I was planning on wrapping the oem headers, turbo housing and downpipe. Will likely get some stainless steel wire to tie it down. Will try to keep 1/4 " overlap. May get some muffler tape also. I kinda am guessing as I have not seem the oem turbo housing and headers but hope I can accomplish this. Will likley presoak with water to aid in a snug fit.....
I live in BC, canada so no salt on the roads so not worried about corrosion.....
 

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have you sean the video of the gti that caught on fire :) WOOT go wrap your dp .. i would think twice before you do it .. even if it is a 99.99% it wont happen it is not worth it .. just spend the money on jethot .. if u have not sean the movie watch it :0
 

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i hosted the movie on this website...and just purchased some yesterday!! wow..

But ive never seen One STi that that has happened to.
It could have been something else with that gti. But yes, go watch that video...its in the non-subaru specific video section of this website
 

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As long as you seal the wrap or cover it with foil, you won't have any problems with fire. Wrapping keeps more heat out of the engine bay than coating plus its cheaper.
 

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rodent said:
As long as you seal the wrap or cover it with foil, you won't have any problems with fire. Wrapping keeps more heat out of the engine bay than coating plus its cheaper.
your wrong .. and it put alot of stress on the pipe .. why in nascar and everything else they coat it .. the old days they wrapped them and it was bad .. but go ahead and do what you want its your car .. have fun

i also cant stand when ppl say it is more money then coating it .. which it is but ppl buy defis and those are a **** ton of money .. U can go get some auto-meter gagues that do the same thing for 10x cheaper .. And the response everyone gives it why put something cheap on are car when it is a 30K car .. i mean come on ppl its the same thing .. dont be cheap it only and extra 60$ more to get it coated .. it cost me 105$
 

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Discussion Starter · #9 ·
Really it was only $105 cheaper?
Come on, you had to remove the headers, I guess the mechanic was free. And shipping was free to get to the coating place, and shipping back was also free, as were the new exhaust gaskets needed to reinstall the headers and again the mechanic was also free for this. Never mind the car sat for who knows how many days without any exhaust. I read on one link someone was waiting a month and still no headers back...
But hey time is not worth money either....
haha
Sorry, I am not making fun of this.
I do realise that coating is probably the better way to do this.
But I do need an accurate assesment of the total cost whether it be time, money, or skills required to install.
 

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two things:

1) if wrapped properly, no stress should be added to the pipe (proper spacing)
2) I have personally sat with a mapp gas (5000+ degrees!!!) torch on FRAYED exhaust wrap from D.E.I and was completely unsuccessful in lighting it or even getting a decent smoulder.

there is some info, for what its worth
 

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The problems arise when the wrap gets oil on it....
 

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Oil should really not touch your downpipe, ever, if at all possible.

Interestingly, we lit an STi on fire a few years ago by NOT wrapping the DP. The power steering lines shifted during a steering rack bushing install and by the end of the test drive the lines burst open from the heat and sprayed flammable fluid onto the piping hot downpipe.

The flames were impressive, but no fire damage was done.
 

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so I bought an insulation wrap for my turbo..
from static x motorsports.
Should I wrap my downpipe as well? I have the wrap for that too.
What steps should I take to ensure that it wont go up in flames? Or should I even bother, and just go with a FMIC?

Houston sucks in terms of HOT weather..
 

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I got thermo-tec on my turbo and it has made a great difference. easier spool...lower underhood temps...higher exhaust velocity :)
 

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Darkiller said:
your wrong .. and it put alot of stress on the pipe .. why in nascar and everything else they coat it .. the old days they wrapped them and it was bad .. but go ahead and do what you want its your car .. have fun

i also cant stand when ppl say it is more money then coating it .. which it is but ppl buy defis and those are a **** ton of money .. U can go get some auto-meter gagues that do the same thing for 10x cheaper .. And the response everyone gives it why put something cheap on are car when it is a 30K car .. i mean come on ppl its the same thing .. dont be cheap it only and extra 60$ more to get it coated .. it cost me 105$
How am I wrong??? Jet Hot wanted over $250 plus shipping to do my APS header and uppipe. Do you want to see proof that wrap keeps the engine comparment cooler? Here you go:

mick_the_ginge said:
I wrapped my HKS exhaust headers before I installed them onto the car, including giving them a good coating of exhaust wrap spray. They were installed on the car for about 1 1/2 years which included about 20+ track sessions at PIR. Recently while upgrading my block I decided to change from wrap to a ceramic heat coat. I used a local company in Portland Oregon to apply a "high temp" ceramic coating to the headers. They are coated inside and out. The ceramic coating is very thin but supposed to reduce under hood temps significatly.

Here you can see them installed in the car
http://www.mickandsarah.com/wrx/misc/wrap-coat-0006.jpg

What I did not expect was what happened next. First track session and I noticed a smell of burning plastic....... Bugger, the bottom of my radiator fans melted!
http://www.mickandsarah.com/wrx/misc/wrap-coat-0007.jpg

As you can see from the above pictures the headers do not touch the radiator, but it is pretty close. 20+ track session with exhaust wrap no issues, one track session with ceramic coating and melted radiator fan.

I am sure for street use the ceramic heat coating is fine, but for the track I am about to re-wrap my headers....
And here is why Nascar doesn't use wrap:

20C - 9.1 Exhaust Manifold
A. Exhaust tubing must not cross over or under the engine.
B. When the NASCAR-approved “Spec Engine” is used, the exhaust header must meet the following requirements:
(1) The exhaust header flange plate must be a maximum of 3/8 inch thick magnetic steel.
(2) The exhaust header primary tubes must be 1-3/4 inches outside diameter, magnetic steel, round tubing from the header flange to the exhaust collector ( “Tri – Y” configuration ).
(3) Two (2) primary exhaust tubes must collect into a two-into-one magnetic steel collector, two (2) on each side.
(4) The two (2) collectors on each side must then collect into a single, magnetic steel collector on each side.
(5) The single collector on each side must have an exit size of 3-1/2 inches outside diameter round tubing.
C. Coated headers will be permitted.
D. Thermal wrap will not be permitted on the exhaust headers or collectors.
E. Spacers will not be permitted between the cylinder head and the exhaust header flange. Only one (1) gasket, maximum 0.075 inch thickness, may be used between the cylinder head and exhaust header flange.

20C - 9.2 Exhaust Pipes
A. through I. remain the same.
J. Exhaust pipes must be made from magnetic steel tubing.
K. Thermal wrap will be permitted to be used on the exhaust pipe under the driver’s compartment area only.
stevenh said:
The problems arise when the wrap gets oil on it....
This shouldn't be a problem if sealed properly or foil is used to cover the wrap.
 

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I've used header and exhaust wrap for years with zero problems, but I have always used spray sealant. In combination, they make a huge difference in underhood temps and it is totally safe.

Good stuff, highly recommended.
 

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Do a search under posts for my name I use to be a big supporter of jethot, but after a lot of lies and bull fed to me about delays I decided to try wrapping. If spaced properly and sealed it will have no issues and does insulate better than coating. The jethot treatment I used was great 2 plus years no wear or damage of any kind but I don't like "LIES!"
If you do a search under my name you will see some of my wrapping pics of an Invidia DP. Never overlap the wrap more than 1/8 of an inch, wet the wrap before installing it. This will keep it tight, and no it should not catch fire unless something like oil gets on it.
 

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Discussion Starter · #18 · (Edited)
I contacted Thermo Tec and this is what they had to say:

Dear Patrick,
There is absolutely no way the exhaust wrap can catch on fire. The material is a fiberglass / silica material that has stood the test of time. We have been selling the wrap for almost 20years, around 100,000 rolls per year, and there has never been a fire. Now if the wrap does get soaked with oil and there is a flame, then the oil itself could burn, but the wrap would not start a flame just by itself even with having oil on it.
There has literally never been a problem with wrap adversely effecting the converter or turbo. Underhood temperatures are significantly reduced due to increased scavenging of those hot exhaust gases.
Just let us know what other questions you might have.
Regards

Jim Henderson
Thermo-Tec Automotive, Inc.
www.thermotec.com
email: [email protected]

I also contacted a local tuner and they also indicated that the wrap will have no negatives if installed properly and will only benefit the engine by increasing turbo spool up, lower engine temperatures that will reduce electronic equipment degradation, and a cooler intercooler. On a dyno the difference will not be noticed as much as teh car will be sitting and the temperature will rise reagardless. But with a little driving and air flow the temperatures will drop significantly.

I have been told to ensure the tape is installed with an equal spacing and overlap of about 1/4 inch but no more (to ensure there is no hot spots) and it is a good idea to spray with high temperature paint to make it last longer by weatherpoofing it. Wetting it will allow a snugger fit and it should be tied down with either stainlees steel clamps, stainless steel piping screw clamps, or stainless steel wire.

Based on this and other research I have done and the subaru engine design which has a top mounted intercooler (which is more succesceptible to heat) and the longer header piping (which reduces exhaust energy), I will be using wrap for my car!
Tks to all for their input...
 

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infinitemotors said:
two things:

1) if wrapped properly, no stress should be added to the pipe (proper spacing)
2) I have personally sat with a mapp gas (5000+ degrees!!!) torch on FRAYED exhaust wrap from D.E.I and was completely unsuccessful in lighting it or even getting a decent smoulder.

there is some info, for what its worth
I hate to tell you but heat is stress!! If you wrap pipes, the heat has no where to escape and will fategue the metal over time, its the price we pay... Thats why I got my headers coated inside and out. The coating will help protect the metal on the inside as well...
 

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Discussion Starter · #20 ·
Yes heat is stress, and the exhaust pipes will not last forever regardless, that is true. However, either your pipes wear faster potentially (with wrap) or everything else in the engine bay wears faster (electronics and everything made of plastic, without wrap).
And we all know hot Subaru engine bays get.
At least with wrap I will have better performance also!
 
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