Exact opposite, it will keep heat in since it cant dissipate it. Just like you wearing a coat!

 

Ok I think I will leave it alone thanks. I run 20w50 syn in June July August. Iam always looking for little ways to keep the engine running cool.
Maybe a better coolant?

 

Exhaust wrap is meant to keep exhaust temps up to maintain velocity and aid in cylinder scavenging. It's not meant to keep anything cool......sean

 

Well if it's keeping heat in, then that's heat that is not escaping. Maybe a byproduct, but it's still a result.

Though IMO 90% of the wrapped pipes are mostly done to cover up a rusty or discoloring pipe, and/or give it a certain hotrodder look.

 

Lots of talk on heat wrap on the cafe racer sites, as wrapped pipes lend themselves to the cafe "look". Most of the guys who really know what they're talking about -as opposed to the hipsters who put image before function -have nothing good to say about it.
(not saying you're an image obsessed hipster, simply making a reference to many conversations I've read on the subject )

One major downside is that when the wrap gets wet it tends to hold in the moisture and eats your pipes alive.

Not as much of a concern on a track bike where things get disassembled and replaced routinely, and the bike is only out on the track in favorable weather conditions, but bad news on your daily rider.

 

Most exhaust wrap on bikes is used strictly for cosmetic reasons. I doubt it makes much of a difference heatwise as it seems to be some kind of mesh, but I have no experience with it.

 

Here you go:
http://www.jegs.com/p/JEGS-Performance-Products/JEGS-Premium-Exhaust-Header-Wrap/1202563/10002/-1

EGS Exhaust and Header Wrap is better than ceramic coating because it does not allow the exhaust gases to cool for better scavenging. Ceramic coatings also do not reduce as much heat in the engine compartment as header wrap does which offers a lower intake temperature, better atomization and more power, period. Made from Vermiculite infused fiberglass which offers a tighter weave, less fraying, more heat retention and is able withstand a constant 1200° operating temperature. We added a special heat treat coating that reduces smoke after installation and handles up to 2000° intermittently. Available in 1" or 2" wide rolls. JEGS Premium Exhaust & Header Wrap is designed for use on all types of exhaust tubing and headers.

Another quote from the same site:

Heat in the right place can help build horsepower. Hot exhaust flows out of your engine better than cooler exhaust. Exhaust header wrap and header blankets can increase your exhaust temperature and increase exhaust flow, helping you build power.

It could be just sales hype from JEGS, but it somewhat supports my previous statement about it's use and intended purpose. I've seen a number of people use this on bikes. Whether to give it a more "hot rod" look or for actual performance. I doubt it would have much effect on a stainless steel exhaust should water get trapped in it. It would dry pretty quickly after running for a short while.....sean

 

Yeah, I'd be worried about the moisture problem.

 

In have seen drag racers wrap their headers, I always thought it was to reduce the underhood temperatures. An engine needs the coolest intake air it can get, the cooler it is the more dense it is, and the more of it you can get into the combustion chamber, which increases power. I'm sure I've heard it advertised for that purpose. For the times I run, it really wouldn't make any difference, and would be a mess to deal with.

 

Yeah, I'd be worried about the moisture problem.

With a stainless steel exhaust? I'm pretty sure that's not going to be an issue.....sean

 

As others have said, the wrap keeps the heat in the exhaust. This can improve performance as Apriliarider said, and will keep underhood/rider temps down (since the heat is staying in the exhaust instead of radiating out to the surrounding air). However, it can cause problems too. It doesn't allow the metal exhaust to radiate as much heat out, so the exhaust pipes themselves experience hotter temps, which can lead to problems with the metal. The wrap can absorb liquids; with water this can mean rust, with coolant or oil this can mean a fire hazard. A lot of the cafe racers probably do it more for appearance than any noticeable function.

They also have ceramic coatings that do the same thing. http://www.jet-hot.com/ is one example. They can be applied to the outside of your exhaust to act like the wraps, without actually having fabric wrapped around your exhaust. However, the ceramic coatings can also be applied to the inside of the exhaust as well. This keeps the heat in the exhaust gas and out of the exhaust pipe itself. Instead of the thermal barrier being between the exhaust pipe and the atmosphere, the barrier is between the exhaust gas and the exhaust pipe. This results in the exhaust pipes themselves seeing lower temps, despite the exhaust gas staying hotter. This also helps keep corrosive crap in the exhaust gases from even touching the metal at all.

Here's a blurb from a Car Craft comparison that I posted on the SyTy board in '02:

Jet-Hot points out that realizing the full anti-corrosion benefits of header coatings requires coating the headers on their inside as well as outside surfaces. Not all competitors coat the inside surfaces which isn't good because exhaust gases themselves contain corrosive compounds. If the inside isn't coated, the header eventually rusts through from the inside out.

Coating only the outside can also cause another problem: Mild steel tubing fatigues when it gets too hot. An outer-only thermal barrier blocks the heat from radiating through the exterior metal surface while the lack of an inner barrier exposes the metal to added "trapped" heat. In a scenario reminiscent of that caused by the dreaded "curse of the mummified headers" (outer cloth wraps used by some racers), the result can be literal disintegration of the mild-steel tubing.

As for performance, the painted headers were 524°, while ceramic coated were 201°. There wasn't much difference in dyno readings, but they had the engine mounted on a stand, not in an engine compartment, plus there were huge circulation fans nearby.

 

In the end the bike should be fine as long as the fan is in working order. It freaks people out when they see the temp gauge climbing, but it is working as designed.

 

On cars, all headers eventually rust through, and have to be replaced. Headers are made of relatively thin steel, and get very hot. That is why auto manufacturers use cast iron exhaust manifolds. They last forever, but are not usually equal length, which has a negative effect on performance. On motorcycles, at least ones with chrome exhausts, they often use double wall pipes, to prevent the outside of the pipe from getting too hot and discoloring. This is purely cosmetic. I loved the blued pipes on my old '66 Bonneville, and I think Triumph may be using single wall construction on some of their newer bikes on purpose so they will turn blue. I remember Honda did that with the pipes on the NT650 Hawk back in the late '80s.