Exhaust Wrap - Insulator or Cooler?

For any of you guys that have wrapped your headers have you noticed if your bike runs warmer or colder?
I was going to wrap my headers to to make the bike run cooler but i was told tonight that although that works on cars it has the opposite effect on bikes, something im finding it hard to get my head round! This may sound like a stupid statement from me, well i gotta learn from somewhere, but i thought it made an engine run cooler?, then it occured to me that if thats true then why don't MotoGP & WSBK teams wrap their exhausts?

Advice appreciated as i REALLY dont want to melt anything!!

i would guess that moto gp bikes as most modern water cooled bikes have the proper cooling capasity designed in. so they dont need an add on band aid fix.

So are you saying wrapping the headers increases or decreases temp?

I can't see how it would change in results.

The wrap is meant to insulate the headers and prevent heat from escaping (radiating) from the headers. This should essentially move more of the heat away from cylinder head before it escapes which should prevent some of the radiant heat effect in the top end of the engine.

That said, since there is so much air moving around the engine I'm not sure to what amount this actually will make a temperature difference.

I do know, however, that exhaust wrap will likely promote rust on your exhaust headers. This is not an issue on a race bike where the wrap would likely be changed each race, but can be very problematic on a street bike.

Thank you for your reasoned answer! The Irish climate is a bit wet even in summer so maybe wrapping isn't such a good idea?

Do you by any chance know what the best way to change silver headers to Black is? PJ1 heat resistant paint or can they be powdercoated?

I don't know about PJ1 - others have used high temp BBQ paint with some success.

I'm looking into ceramic coating here at the minute but can't find anyone local so i may need to send it to England.

Was going to mention that, but I had only heard of guys doing the inside of the headers - similar benefits to wrapping.

750steve wrote: So are you saying wrapping the headers increases or decreases temp?

That's a complex question. Strictly from the point of heat flow, it increases engine temp by adding insulation... but it's complicated. Making the exhaust gas hotter makes it flow better, which improves flow through the engine. That changes the "lean" factor which actually has a significant effect on how hot it runs.

750steve wrote: Thank you for your reasoned answer! The Irish climate is a bit wet even in summer so maybe wrapping isn't such a good idea?

Do you by any chance know what the best way to change silver headers to Black is? PJ1 heat resistant paint or can they be powdercoated?

Here are a couple folks who had them ceramic coated:

kzrider.com/forum/11-projects/169462-bui...=20&start=520#422993

kzrider.com/forum/advsearch?q=ceramic&se...ildforums=1&limit=20

kzrider.com/forum/11-projects/378697-pro...=20&start=120#496717

here is a quote from an exhaust wrap company.

Premium Exhaust Wrap Details


Exhaust wraps help to retain heat in your exhaust system, which increases horsepower while reducing radiant heat damage. By wrapping the exhaust system it maintains hotter exhaust gases, decreases the density, and allows the exhaust gas to exit the system faster! Greater exhaust scavenging is produced and lowers intake temperatures: that equals more horsepower.

Found this in a UK magazine.........to add yet further controversy on the matter!!