header wraps, a good idea? Options

[DeW_H0e_GT]

hi all,
does any one installed some header wraps on their ride?...i heard it actually cool sdown the header's temp.....any gains expected from it?

[Kwanza26]

it cools down the engine bay temp but can sometimes cause cracks in the header...

[GT4WRC]

it cools down the engine bay temp but can sometimes cause cracks in the header...
[right][snapback]284050[/snapback][/right]

Yep. The wrap is designed to keep heat 'in'. This has two effects. Firstly, it keeps the exhaust gasses hotter and, as a result, the travel faster which is good for performance. This is especially so on a turbo car. Secondly, and not so good, it also dramatically raises the temperature of the exhaust manifold. A manifold which has not been designed and built to withstand such high thermal stresses will eventually crack. Obviously not good.
Another issue which people don't realise, is that putting untreated exhaust wrap on a cast steel manifold can dramatically shorten its life. Why? Because the woven 'bandage' wrapped around the manifold absorbs moisture and it becomes trapped under the layers. Moisture and steel are not the best room mates for obvious reasons One potential solution is to coat the wrap with several coats of VHT exhaust paint to help keep any moisture out.
HTH
Gary

This post has been edited by GT4WRC: May 7, 2005 - 4:41 PM