exhaust wrap

[Scanny]

i just happened to spot a jap car mag today and flicked through it. one article was regarding some kind of wrapping for the exhaust manifold. apparently it insulates the heat and can add a few more BHP. has anyone come across this or tried it?

[bradc]

I don't think it will make much power, but it does have the ability to lower engine bay temps

[Beastlee]

Was talking to MarkSanne and MarkD last week about this as I am awaiting the final RPW downpipes. I mentioned I would like to dot he heatwrap on them as seen elsewhere on the forum but was warned that it can cause premature rusting. This shouldn't be an issue on a stainless set though. I think anything that can be done to reduce the engine bay temperature is a good thing.

[Ryan]

Was talking to MarkSanne and MarkD last week about this as I am awaiting the final RPW downpipes. I mentioned I would like to dot he heatwrap on them as seen elsewhere on the forum but was warned that it can cause premature rusting. This shouldn't be an issue on a stainless set though. I think anything that can be done to reduce the engine bay temperature is a good thing.

I had heat wrapped headers on my Celica and also was concerned about the rusting. In wet climates, the cladding absorbs moisture and if you don't use your car that often well... I guess it's quite possible it could rust.

[psbarham]

exhaust wrap make a fair bit of difference.
It keeps the exhaust gasses hotter for longer so the flow better beacuse the density is less.
It lowers the under bonnet temps so the intake system stays cooler.
The one thing you do have to watch for is with cast manifolds, because it retains the heat it can cause the manifold to crack.

[peter thomson]

I had the wrap on my stainless steel manifolds on my Landrover and my brothers SD1 Vittesse and they both rusted due to the wrap holding moisture but there are a few different ones availble now and they may not be all the same .Agriemech have quite a few listed

[bradc]

Personally I don't get the whole retaining moisture thing. When you're driving the car the exhaust is so hot that any water that gets on it via spray from the front wheels or puddles will be instantly vapourised, and when you're done driving, how is water going to get to the exhaust?

[peter thomson]

Winters are a lot tougher here with the added benefit of salt and a lot of snow. The manifolds on the landrover lasted 2 years but the Vitesse ones lasted 5 .Being a car it did not get such a beating compared to the landrover. The stainless steel was only T304 grade I think it' called rather than T404. Cant remember if that's the correct designation but along those lines.

[bradc]

yeah true. I guess the best thing is stainless steel :)

[Throbbe]

The one thing you do have to watch for is with cast manifolds, because it retains the heat it can cause the manifold to crack.

In particular, make sure you wrap it evenly to avoid creating hot spots/differential expansion.

While it is of benefit, I'd regard it as one of those mods that isn't worth the bother until you need to start chasing the last few bhp.

[Scanny]

the time is coming to get a new exhaust and im not messing around with a halfords shelf stock. Im going for a full stainless steel system from where it joins the block to where it sticks out the back end.
Is it worth asking them to wrap it or not? I dont want to waste money by fitting something that does nothing or by having it fitted later. I need to know if its worth fitting this stuff to an exhaust while they are building it

[Davezj]

from what remember the exhaust wrap it self is cheap as chips. the cost involved in stripping down to fit it is the wrap is major cost implication.

so if you are doing the exhaust from scratch then it will cost for the wrap only. Go to ebay and put exhaust wrap in to find out prices.

If i was doing an exhaust from scratch then i would wrap down to the cat. And take the risk of rusting.
This means the down pipes would be very wet. The grade of stainless steel they make your exhaust out of will not be surgical quality so will have iron inclusions in it, which will rust. Thats why cheap stainless steel knives show rust makes on them, it is the iron inclusions.

If you find you don't want the wrap on there in the future you can cut it off much easier than fitting it after the installation.

what they generally do is to start the wrapping then put a wire tire round the exhaust carry on wrapping then another wire tie and wrap, etc, etc , etc.

I believe the wrap should be applied soaking wet, so when it dry's it shrinks and tightens up. when it gets wet next time to won't just go limp and start to unravel.

[peter thomson]

Ask the supplier how the wrap will affect the guarantee as well if the manifold fails in the future do to rust. Agrimech sell different types of wrap. Some may be better to seal the exhaust to prevent water getting in and causing any damage

[Turbo_Steve]

If you're splashing the big bucks on getting an exhaust made, you may wish to consider ceramic coating as an alternative (or complement) to wrapping it.

[psbarham]

The grade of stainless steel they make your exhaust out of will not be surgical quality so will have iron inclusions in it, which will rust. Thats why cheap stainless steel knives show rust makes on them, it is the iron inclusions.



i think you'll find it surgical stainless that rusts, and food grade that doesn't, surgical gets cleaned frequently so the corrosion doesn't matter, but in food factorys the pipes can't be cleaned so they use the higher grade which is now know as food grade.

[Davezj]

realy that interesting.

thanks for the info.

[Scanny]

havent even heard of that steve. Interesting though. You have probably gathered that im not after a £300 system so anything that increases performance and lifespan is worth looking into

[psbarham]

realy that interesting.

thanks for the info.

no problem mate, i always thought the same as you, but i was talking to my dad (40+ yrs in engineering)a few yrs ago and he said that the surgical stuff is crap for industrial use, great for a cutting edge though.

[bigoxo]

Just thought I'd mention that military aircraft use "exhaust wrap" all over the place, it's called a muff or a thermal blanket/insulation. It helps alot to keep the heat down away from the pipes in all air systems including exhausts.

[Davezj]

i used some ceramic based gloop on my exhaust system.

it is designed to coat the inside of a kiln. on all the metal surfaces. i think it is more of a protector than a good insulator but i thought i would give it a go. i am going to put a few more coats on it soon so after that i will do some temp measurement on the inside and out side of the exhaust to see if there is a good insulative properties.

It is not cheap but if it works, well worth it.

i have only done the cat back section so far as this was the bit i took off. soon to take the down pipes off though. so manifolds and down pipe and turbo exhaust case will be done next.

If nothing else it is a great corosion prevertor and good for about 1800C.

[Turbo_Steve]

I've used it on other cars with mixed results. I've found it allowed me to run more timing on several, whilst on two they seemed a tiny bit more det prone before mapping. Whether this is because the bores are staying warmer, gas is flowing faster / slower I couldn't say.