10 replies to this topic

[minilee94]

I've got some heat wrap to wrap my stainless manifold I've heard of people saying it can make stainless steel manifolds crack

Is this true and should I wrap it or not

[IainStallard]

Heat wrap can cause any manifold to crack. The extra heat can make the metal glow underneath and any gaps can cause extreme heat to build up in one place and make it brittle

[Steve220]

If its cracking its either cheap manifold with rubbish welds or an inferior grade of stainless steel. I heat wrapped downpipes and got the manifolds coated by Zircotec which worked out much better.

 

http://www.zircotec.com/

[Phil-R]

I've heat wrapped one manifold and found the effect to be marginal if there was a difference at all. I bought a few different ones and used the one that was visually the best quality. After 1 year of weathering it was brittle, falling apart and unravelling under the vehicle.

[Steve220]

The difference won't be noticeable, but it will reduce under bonnet temperatures which is the main point. Proper heat wrap is expensive, there is just too much cheap rubbish on places like eBay which will fall apart over a short time.

[Cooperman]

It is really not worth doing asyou do risk the manifold coming to pieces and the benefit(s) are marginal at best.

[Phil-R]

The coating sounds interesting. I will need to do another turbo manifold soon so wonder if I can just weld it in mild steel instead of stainless, and coat it to make it last and keep the heat down?  What sort of price do they charge?

Edited by Phil-R, 02 December 2014 - 05:13 PM.

[racingbob]

I wouldn't use it again, except on a race mini and yes the expensive stuff only

 

the cheaper stuff its absolutely rubbish

[Dan]

The heat has to go somewhere, on my car although it was cooler behind the engine it was a hell of a lot hotter under the floor. You could feel the heat through your shoes (with carpet and underlay fitted) and the exhaust mountings started melting. There is little point and I won't do it again. Once you are driving it's not really hot under the bonnet anyway.

[Earwax]

Not really required or wanted for a road application.probably required on turbo  but don't know Purpose in race cars ( my opinion only) is to

a) assist reduce potential for detonation, when engines are right on the tuning edge of detonation , extra heat makes a difference

b) stop melting, expanding, seizing of components,  again it is one area that just under is much better than just over in heating.

c) possibly reduce temp of air charge from under bonnet... not really evidenced

 

In race applications where normally only 20 minutes of thrashing it works well, it does its best to prevent heat from escaping in the wrapped zone, but in the unwrapped zone as Dan found out the thermal energy is still there.. 

 

don't know the recommendation for endurance type race events.... it could lead to cracking

 

also i havent been able to find any comparisons on wrapping vs ceramic coating.. whether one is better than other

[Tupers]

I'm not keen on heat wrapping. We unwrapped a Manifow LCB that had done a season on an MG Metro race car and there were a load of pin holes in it where the steel had basically just burnt away. 

 

The modern internal coatings sound interesting but would still result in high cabin temperatures in a road car.