Exhaust wrapping - hot or not?

Posted by swade on May 26th, 2008 6 Comments Printer-Friendly

This is one for the performance fans out there. I don’t really know much about this, despite the fact that the exhaust on my 900 is wrapped.

The theory here is that once you wrap your exhaust manifold in this heat-absorbant bandage, it retains a lot of heat in your exhaust headers instead of radiating it into the engine bay. The result is a quicker evacuation of exhaust gases from the combustion chamber, as well as reduced heat in your engine bay.

The reduction in ambient heat is supposed to be of benefit (especially to turbocharged engines) because cold air is denser and you can therefore get more punch from your turbo by keeping the air temp down (which is why we have intercoolers, water injection and cold air intakes - they’re all trying to do the same thing). The other advantage in some cars will be the reduced possibility of damage to heat sensitive parts, wiring etc.

Here’s what the finished product looks like (not a Saab manifold):

Wrapped exhaust

The bandage is quite thick and the whole process is a) relatively expensive at around $80 for 100 feet of tape, b) time consuming, and c) awkward. You have to try and wrap the entire manifold and tight spots can be a pain in the backside.

As mentioned, I’ve got a wrapped exhaust on my 1985 Saab 900, however I’d be interested to hear the thoughts of others who have done this. My exhaust was already wrapped before I bought it, so I don’t have a before/after experience to relate here.

If you’ve wrapped your exhaust, did you find that it had any effect of the performance of your car, even if it’s just keeping temperatures down a bit rather than a noticeable performance gain? Even a small effect?

Did you think it was worth the time/money/effort?

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There’s a quick piece on the process of wrapping one’s exhaust here.

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greenmatt said:

A lot of exhaust manufacturers will not warrant their exhausts if they have been wrapped. Wrapping has been superseded by ceramic coating which does a similar job but inhibits corrosion as well.

-May 26th, 2008 at 11:20 am
Richo said:

You could always get Fiddy Cent or Eminem to give it a go… I hear they’re quite good at wrappin….

-May 26th, 2008 at 11:21 am
socal_eric said:

The theory sounds nice but in practical applications the wrap hasn’t shown much if any significant performance gains in a lot of other applications. If you have a bad underhood heat problem on a race car or heavily modified vehicle it might be beneficial for reducing that, but as mentioned the newer ceramic coatings may be a better option. Down sides are that the wraps can usually trap moisture between the wrap and header/manifold which can greatly accelerate the degradation of the metal. Warping can also be an issue on some cars.

On all my turbo Dodge’s and turbo GM’s (as well as naturally aspirated cars) I’d avoid the stuff like the plague. I’ve seen too many issues with it leading to premature damage to the exhaust components and insignificant performance changes for the vast majority of street and mildly modified race cars I’ve seen. And if you’ve got that bad of an underhood heat problem it might be wise to look at the cooling and exhaust systems as a whole.

-May 26th, 2008 at 2:21 pm
900_S said:

Yeah, I’ve heard the same thing that socal_eric stated: the bad far outweigh the good.

-May 26th, 2008 at 3:58 pm
Drew B said:

NO

-May 26th, 2008 at 7:08 pm
Eirik said:

Another argument is that faster the exhaust-gas cools down, the faster it will leave the exhaust pipes. That’s also one of the reasons for a 3″ downpipe. With the bandage, the exhaustgas will keep it’s temperature better, and as we all know - warm air has lower density than cold air. So unless you have a big problem with engine bay overheating, I’d say you should remove it.

-May 26th, 2008 at 9:00 pm