Exhaust Heat Wrap

What are peoples thoughts on exhaust heat wrap ?? I'm 'attempting' to change my manifolds in the next couple of weeks and wondered if there are any 'cons'. A couple of years back I wrapped the manifolds on my Caterham 7, a well worthwhile job due to the close proximity of the solenoid etc, causing the Caterham Click.

Just done my motorbike! Love the stuff! However...... the bike doesn't see the rain or any wet at all whereas the car may. Many people have said about damaged under wrapped car exhausts as moisture can be trapped long term in it against the exhaust and therefore I've not done mine. Just an opinion

I've done it with the old fashioned hessian looking webbing tape secured with stainless metal zip ties on a couple of my classic cars just to keep the heat down in the engine bay and it has certainly done that. Being in the engine bay it never gets wet and anyway the heat of the manifolds would soon dry it out. Not sure what you are trying to achieve by doing this but for heat reduction then I think a ceramic coating is meant to be the best (quite popular amongst the more expensive classic car fraternity)and would probably be more in keeping for the 911. This company seem to be popular and well regarded: https://www.zircotec.com/ I used the wrap simply because it was more period for the classic stuff and it was obviously way cheaper. Apparently doing this can also help speed the air flow through the manifolds (can't remember the scientific explanation) but can't say I noticed much difference - with all 68HP on tap in the SAAB v4 who needs more power anyway. Cheers.......Ian

My k series caterham has been done. The type I used had a spray paint to go on once wrapped which helps with general fraying. Cool It thermo-tec not sure if still available?? There was debate on Blatchat (Lotus Seven forum) several years ago whether the wrap could cause heat build up in the head and soften the ally. No evidence appeared for or against this theory. I wouldnt bother on the porsche as they hang in the airflow (unless stationary alot!!) Ian

I did it to both banks of a TVR V8 which generated a lot of heat in a small plastic body. I also did it to a modified Alpina in search of any extra bhp. To be honest though, on a 996 I think you'd be solving a problem that doesn't exist!

I did a some on my old Impreza. It had heavy cast manifolds so it was ok but when they get wet they will rot all underneath. I get water dripping from the joints in my exhausts so if it was covered with wrap, it's just going to get damp and rot

I have used kevlar wrap on my bikes and, particularly, on the Benelli Tornado it made a huge difference in the volume of heat being transferred in the confines of the fairing and a most definite reduction in running temperatures, especially in traffic. The downside, and I suspect it will be much more problematic on an everyday driver, was that when wet it generated huge plumes of steam until it dries off. Lots of retained damp followed by clouds of hot vapour are maybe not the best for a tightly packed engine bay on a Porsche. I intend to have my next set of manifolds ceramic coated for this very reason.

The headers on my Cayman were wrapped when I bought it. When I replaced them I had the new ones wrapped too. Has it made any difference ? Dunno.... The car has serious engine temperature issues, so my theory was that anything that takes heat away from the engine bay has to be worthwhile.......?

I had 'primary black' zircotec application applied to the factory manifolds on my 996 a year or too ago... thinking being to potentially gain a bit more corrosion protection as much as anything else... the 'anything else' being faster overall gas exit through the exhaust who knows is anything at all was achieved through this - looking under the car now, you'd be hard pressed to know that anything had been done

It's totally pointless on an NA 996. The manifolds and other pipes are exposed enough for heat in the engine bay not to be an issue. As for making the exhaust flow faster, if anyone can prove there is a measurable power/flow advantage I'll eat my hat. I'll bet there are videos on youtube that validate that wrap or ceramic coatings on an NA exhaust is snake oil. It would also be a major ball ache when it inevitably starts to degrade and fray and unwrap itself. That's not to say it's pointless on all cars, as other posters have said already. I used to race a single seater that had exhaust wrap on to protect the plug wires from melting on the headers. On a turbo car, exhaust wrap is worth having because it keeps energy in the exhaust by stopping the gasses from cooling and contracting before the turbo is reached.

https://www.youtube.com/watch?v=O1bXPNy1Yn4

Sadly the ceramic temp diff part of the test in the video was comparing apples and pears, I would expect a black header to give off much more heat that a silver one simply from its colour, even without ceramic coating. Simple physics.