Exhaust/header wrap will decrease your engine bay temperature, improve cooling and add horsepower. Please read this description thoroughly for more information about this very helpful but often misused product.
When you add horsepower to an engine, one side effect is added heat generation. Most engines are designed to operate at 180F, however the exhaust gasses that leave the engine can easily be over ten times hotter than that, and it's common for turbos, exhaust manifolds and exhausts to sit right up against the engine or oil pan! When you have something that is 2000 degrees about two inches away from something you're trying to keep at 180 degrees, it's just common sense to use some kind of insulation. As an added bonus, you get better exhaust scavenging which will add some HP by keeping the heat in the exhaust gas.
Do you know how hot your engine bay is? You've got a big chunk of iron and aluminum and a couple gallons of water at 180 degrees, so that's a good starting point. Exhaust gas at up to 2000 degrees leaving the engine just exacerbates the issue. But what about all the sensitive electronics and expensive performance parts you want to keep cool? And what about your intake pipe which carries nice cool air from your intercooler (or outside the car) that you want to keep well below your engine temperature? Heat radiating from your turbo and exhaust is the #1 cause of performance-robbing engine bay heat, and probably the #1 cause of failing alternators and similar electronics in that area. Help control the problem by insulating your hot exhaust components.
Header wrap has gotten a bad reputation for fears that it causes exhaust parts to rust or fatigue prematurely. While rust is always a concern - wrap or no wrap - here are some ideas that might allow you to get all the great benefits of this product while preventing the drawbacks.
- Use the right product. This header wrap is 1.5MM thick fiberglass, which is ideal for most street or race cars, trucks, bikes, or boats. It substantially insulates exhaust parts while allowing some of the heat to escape, preventing overheating and fatigue (or "burn-out", as it's sometimes called). Do not double wrap, and do not use too much overlap! The recommended amount of overlap to use is 1/4".
- Don't go crazy. There is definitely such a thing as too much exhaust insulation. Over-insulating exhaust parts is the primary cause of parts fatigue and early failure! There are probably over 100 different types of exhaust wrap, many promising better insulation at an increased price. But you don't want better insulation; you want exactly the amount of insulation that this product offers. If you use excessive overlap, double-wrap, or use overly aggressive exhaust wrap, you'll be much more likely to have problems. Furthermore, if you use too much exhaust wrap in the same place, it can actually prevent the metal from expanding properly, compounding the problem.
- Install dry. It's been suggested by some websites and manufacturers of exhaust wrap that you get it damp prior to installing. This makes it easier to install and gives you a better seal to hold in more heat. It's hard to say how much damage would be caused by this one-time moisture, but it probably doesn't help. Clean and dry your exhaust parts before installing, and install the product dry to get a good head start on rust prevention.
- Keep dry. The main reason exhaust wrap can cause premature rust is because it holds moisture. If you're cleaning your engine bay, go ahead and put a plastic bag over your wrapped headers - the cleaning supplies won't do much to clean the exhaust wrap anyways. If you happen to drive through a lake by mistake, consider removing the header wrap, drying, and re-installing. If you drive through a lake on purpose and regularly, using header wrap probably isn't the best idea... unless your components are stainless steel.
- Consider painting. Paint is the most common way to prevent rust in every application from bicycles to aircraft carriers. If you paint your exhaust parts with a high temperature paint and then wrap them, the rust issue will either be reduced or completely eliminated. Header paint is available at many auto parts stores. Note that you should use a paint rated for at least 2000F. Some people have said that no paint can withstand this kind of heat for a long time period. Our recommendation: we believe paint can withstand the heat if it's properly rated, and if it doesn't help or flakes off, all you've lost is a $5 can of spray paint.
- Consider spraying. There is a silicone spray on the market designed to be sprayed over header wrap to prevent moisture collection. Many people recommend this product, but it seems equally likely to hold moisture in instead of keeping it out to us. Furthermore, it might change the insulating characteristics of the header wrap. Our recommendation: paint before wrapping, but do not use silicone spray.
When we were deciding if we were going to carry header wrap, we read many user testimonies for and against the product. It seems most people just install header wrap with no special considerations and drive for 20 years with no problems, while others have bad luck with the product right from the get-go. By using the tips above we believe you'll have a stable and valid way to increase power and improve engine cooling while maintaining reliability.
Note: it is normal for exhaust wrap to smoke and smell funny for a couple hours after installation.
