<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:<hr /><font size="1" face="Verdana, Helvetica, sans-serif">Originally posted by Pascs:
<strong>Wrapping the exhaust manifold will keep the heat in the exhaust. I have done this to my car.
I was already aware that it can cause cracking but thought I would give it a go. If the manifold cracked I would have an excuse to buy the Supersprint one.
I have noticed that the Novitec exhaust system that I have fitted runs very hot. The boot area above the rear silencer gets very hot - don't know if this is due to more heat in the exhaust or not - wouldn't have thought so.
Best bet is to insulate the air filter box and trunking. This gets very hot from the engine heat and the cold air passing through it will obviously heat up. Only down side is that it looks really untidy.</strong><hr /></blockquote><font size="1" face="Verdana, Helvetica, sans-serif">Will themal wrap really cause the headers to crack? Any performance gain on after wrapping your exhaust headers?
An extract from the FAQ of Design Engineering Inc.
Question: Does using Exhaust Wrap on my headers cause premature header failure?
Answer: NO! Over the years, exhaust insulating wrap has received a "bad rap" (no pun intended) and has been attributed to header failure. Studies have shown that properly insulated headers can enjoy an equally long life as their un-wrapped counterparts. As the word circulated that exhaust
insulating wrap worked for obtaining lower underhood temperatures and gaining a horsepower
advantage, many users got wrapped up (that pun thing again!) into the age long train of thought, which is - "IF A LITTLE IS GOOD, MORE IS BETTER!" This could not be further from the truth.
Excessive overlapping, double wrapping, etc. completely "mummifies" each primary tube, thus
decreasing their natural and needed ability to expand and contract as the exhaust heats and cools. Now perhaps you can begin to understand where these half-truth rumors originate.