Exhaust wrap?

[chungdae]

So, I am about to make a decision on an exhaust and now considering if I should put exhaust wrap on the headers? Any suggestions why I should or shouldn't do it?

[Dan Kyle]

Originally Posted by chungdae

So, I am about to make a decision on an exhaust and now considering if I should put exhaust wrap on the headers? Any suggestions why I should or shouldn't do it?

Before I do something, I like to have a reason to do it.

What would be your reason to use exhaust wrap??

On Titanium headers, only the header you would NOT want to wrap them, they can overheat.

[chungdae]

Ah, just curious why I should and why I shouldn't. Now I have a reason why I shouldn't!

[Mrgrn]

you can wrap ti pipes no problem. make sure you chance the wrap yearly but i have ciustomer who have wrapped thier ti pipes for years will NO issues.

Also ti can be ceramic coated but ti offers great heat transfer so i am not sure it might be worth it for your application unless you are racing

[Dan Kyle]

Originally Posted by Mrgrn

you can wrap ti pipes no problem. make sure you chance the wrap yearly but i have ciustomer who have wrapped thier ti pipes for years will NO issues.

Also ti can be ceramic coated but ti offers great heat transfer so i am not sure it might be worth it for your application unless you are racing

Take a look at this chart, the LOWER the number the Worse the Heat conductivity.

Thermal Properties of Metals, Conductivity, Thermal Expansion, Specific Heat - Engineers Edge

But this is not the reason to use or not use a wrap, as it is not conductivity that the wrap is holding it, it is convection, the ability of the Ti to get rid of heat, Ti is again like stainless steel, it does not convect to air well.
In an Exhaust system this is a good thing, which is one of the reasons exhausts are wrapped in the first place, to hold heat in.

This is another reason you do not need to wrap Titanium or Stainless steel exhausts.

Most Titanium exhaust systems use Commercial pure Titanium, at 600C it will start to lose strenght, over continued use it will crack. This is why you do not wrap Titanium where the exhaust is the hottest, at the headers.
Farther back you can wrap it all you want, as it is no longer that hot.
Some compaines like Akrapovic use other alloys as well, these are absolutely needed in Car exhaust systems, and are good up to 800C.

[Mrgrn]

[QUOTE=Dan Kyle;75257] it is convection, the ability of the Ti to get rid of heat[QUOTE]



like i said, thanks for vote Dan

ti cools quickly which is nice for a average rider to not have the heat pouring up on you when stopped but fir best exhaust flow holding the heat(racer) in with a wrap might be warranted

i happen to like ceramic coating the best although i have used wrapped for years and even wrap on ceramic coating. i have seen 2 hp more from just coating inside and out never mind the heat protection it offers

my suggestion is to think what you are after with doing a mod or improvement and weight the pro's and con's and go from there

i would not worry too much about gaining or losing HP on your bike if that was your line of thinking

[chungdae]

Ah ok great! Thank you!

[Godzilla]

Correct me if I'm wrong, but Ti does not cool quickly. It has a higher SHC than stainless steel, so it has more heat energy for the same temp, also it has a lower thermal conductivity, so heat flows through it slower. Both of these should make it cool slower.
Also (I did not know this, but if Dan is correct) it loses heat from the surface to the air by convection slower. This would also make it cool down slower, retain its heat longer.

[bobafeets]

I understand where you are coming from chungdae. I like the look of wrapped exhaust but sometimes it isnt the best thing mrgrn is right thought. you can wrap towards the back of the exhaust. hell some mornings before work i warm up the bike and warm my hands on the exhaust. in all actuality. if MOTOGP teams arent doing it its probably not beneficial. not to say we all take our notes from there. and actually...im not sure motogp DOESNT wrap exhaust. imma shut up.

[Mrgrn]

Originally Posted by Godzilla

Correct me if I'm wrong, but Ti does not cool quickly. It has a higher SHC than stainless steel, so it has more heat energy for the same temp, also it has a lower thermal conductivity, so heat flows through it slower. Both of these should make it cool slower.
Also (I did not know this, but if Dan is correct) it loses heat from the surface to the air by convection slower. This would also make it cool down slower, retain its heat longer.

density

all thin ti pipes i have worked with and or owned have cooled very quickly vs stainless

i own several bikes and have ridden them back to back to back and FWIW the ti pipes you can put your hands on minutes later while the SS pipes hold that heat many times longer

try putting your hands on ti cans, they cool in like 2 minutes