The V8 Owners Forum -

Hi,do any of you guys run with thermal exhaust wrap? Does it do the things it claims to do? Going to be running a fairly tuned 4.6 in my TR7 and would like to keep things cool under the bonnet.Will be running 4 branch manifolds,how easy to wrap these or do you end up looking like a mummy
Cheers for any info
John.

I've heard that ceramic coating does a better job

Ian

Lots use it so guess it must have some good effect, but I didn't like it; had some on mine for a while. It discoloured, and held moisture after a cold night. Also was itchy on the skin being fibreglass. I took mine off and didn't notice a difference, not to say there wasn't one though. I also did other things that were more effective (vented bonnet, better rad, better fan).
There's some gear with copper wire in it, that might perform better & look nicer for longer, think Agriemach do it & poss others,
cheers,
Bill

i used wrap,
never again, it rotted out my manifolds as quick as anything due to it holding moisture.

same here i caught mine before too much rot

ceramic coatings the route im taking when i get my next ones

Thanks for the comments Gentlemen,fast going of the idea,using stainless steal manifolds so corrosion not to much of a issue but dont need hassle of the stuff falling apart.Anyone recommend a ceramic coater and what sort of cost involved?
Cheers John.

john 215 wrote:Hi,do any of you guys run with thermal exhaust wrap? Does it do the things it claims to do? Going to be running a fairly tuned 4.6 in my TR7 and would like to keep things cool under the bonnet.Will be running 4 branch manifolds,how easy to wrap these or do you end up looking like a mummy
Cheers for any info
John.

John, The following extract from my essay on exhaust systems may help.

Returning again to the postulation that “a bigger exhaust is a better exhaust”, let’s look at the size of the pipes from a different perspective? Heat! Exhaust gas is hot, and it would be good to keep it hot throughout the exhaust system. Hot gas is less dense than cold gas, so the colder the gas the heavier it gets and therefore takes more effort to remove it from the system. Larger pipes give the hot gas an opportunity to slow down and give the gas more time to cool en-route to the tailpipe.

We don't want our engine to be pushing a heavy mass of exhaust gas out of the tailpipe and it is not just that an extremely large exhaust pipe will cause a slow exhaust flow, which will in turn give the gas plenty of time to cool off en route. Overlarge piping will also allow our exhaust pulses to achieve a higher level of entropy (Sorry! Entropy is the way energy spreads out in a process), which will take all of the hard gained header tuning and throw it out the window, as pulses will not have the same tendency to line up as they would in a smaller pipe.

If keeping the interior of the exhaust system as hot as possible is an advantage, then coating the entire exhaust system with thermal insulation material, such as header wrap or a ceramic thermal barrier reduces the cooling effect significantly. Cost may be prohibitive but a bonus side effect would be a cooler engine bay and down-pipe area.

You can access the whole article at :

http://uk.blog.360.yahoo.com/blog-CxcM5 ... H7XAU?p=41

or via my Blog.