Exhaust wrap on a 2 stroke?

[TheNewn]

I've seen several 4 stroke pipes with exhaust wrap on them and they looked pretty nice in my opinion, but what i havent seen is a 2 stroke with their pipe wrapped, anyone have this?

My main question is, is there a reason i havent seen any? is it not advised for a 2 stroke pipe? Any bad things about it?

I want to wrap mine all black, i think it would look really nice on the quad.

thanks

[GPracer2500]

I'd guess a typical two stroke pipe will perform close to the same whether wrapped in insulation or bare. Changing the temperature of the gases inside the pipe does change power characteristics but I'm guessing the change would be relatively small in this case [shrug]. It'd take some research to figure out how the power characteristics would change (could get better, could get worse). On a four stroke, keeping the heat in is almost always good. On a two stroke expansion chamber I'm less clear on what happens.

I'd be a little concerned about the engine temperatures increasing some. When you're "on the pipe", a significant portion of the a/f charge burned on each power stroke spends some time in the exhaust before it gets pushed back into the cylinder. I wonder if a wrapped pipe would lead to higher engine temps? Note: this doesn't happen on a four stroke but because of the way a two stroke exhaust functions, it might happen.

And finally, I think it would be really hard to cleanly wrap the cone shapes of an expansion chamber. I've wrapped four stroke headers with traditional fiberglass header wrap and even on those it takes some work make it around the bends cleanly. No header wrap I've seen really stretches like I'd think you'd need it to on an expansion chamber.

If you want black, I'd look into a hi-temp paint or maybe JET-HOT's JetHot 2000 coating. They've got other colors too like blue and grey.

$0.02

[Rip_Tear]

I was thinking about wrapping my pipe as well, but I don't know how it would look with the expansion etc.

I do not believe there would be any problem, I've seen sled pipes wrapped, so I can't assume there would be any problem, or they wouldn't do it...?

A coating would a much better idea, but different look and cost. I would suggest looking into both a bit more before deciding. If you do wrap your pipe post up some pics so I can see ;)

[machwon]

In an exhaust system, the air velocity in the pipe will depend on the temperature. Hotter pipe temperatures mean faster speed/sound velocity.

Pipe temperature can be important, But there are many factors involved. Most sport/performance ATV's use gear transmissions which typically have too broad of a power spread (2-2500 rpms) to notice a difference. Snowmobiles on the other hand operate in a more narrow RPM range 5-700 rpms because of CVT (clutches) and so the effect is more noticable.

For instance, my sled won't hit peak rpms unless the pipe is warm. My clutching is tuned for max performance in a certain range and if I can't hit those rpms I lose 3 sled lengths. It usually takes 2-3 passes when running it from a cold start up. Due to the increased heat, this increases the speed of air, which in effect shortens the pipe and raises the peak operating RPM power.

Try searching on the internet for an article by Kevin Cameron, he's very knowledgeable on this subject.

[TheNewn]

So the jist of what im getting from you is that it's probably not a good idea and i should just stick to high temp paint?

Interesting info

[C-LEIGH RACING]

I guess to kind of explain in a short version what happens in a two stroke pipe thats been wrapped, you first need to know that long built pipes are more suited for bottom end to midrange ported engines to cause a slow taveling pulse wave & short built pipes for upper midrange to top end porting causing a faster traveling wave.

A pipes shape, over all lenght, lenght of cones & their angles & inside DIAs are all about enhancing the pulse wave that travels through the pipe.
Just like Machwon said, warm or hot gasses flow faster than cold gasses & when you wrap a pipe you in turn hold heat which would in turn cause the wave to travel faster.
This is getting more complicated than I have time to finish, but if you wrap a pipe you change the build of a pipe just a small amount & cause the wave to travel faster which could in turn match the pipe up better with the cylinder porting or cause it to be off even more than before the wrapping.
Sometimes builders, in a test of sorts, will wrap a pipe in different sections of the pipe to change the wave travel in that section & if a performance change is noticed after that then the pipes build will be changed.

Whueee, I smell sawdust burning after all that, but hope you understand.
Neil

[250Renvy]

[QUOTE]Originally posted by C-LEIGH RACING
[B]you first need to know that long built pipes are more suited for bottom end to midrange ported engines to cause a slow taveling pulse wave & short built pipes for upper midrange to top end porting causing a faster traveling wave.

A pipes shape, over all lenght, lenght of cones & their angles & inside DIAs are all about enhancing the pulse wave that travels through the pipe.
[Quote]

Neil,

Not factoring in the variances between the different pipes, just the general fact that most pipes extend through the frame - similar to fmf pipes.
How does a DG national pipe compare to these because to me it looks like the same bends as a stock headpipe? Does that make it more for mid to top? Or is it just a good all around pipe?

[JoE4554]

Well i just tried putting some on my 300ex with a white brothers e-series full exhaust this past weekend. It worked out terribly. The bike would start and barely run. I took it off , the whole pipe was bright orange. But after that, it ran perfectly fine. So i dont know.

[gregw338]

I wrapped my full exhaust on my z453 just because the header pipe gets so hot it will melt my boots and I have a 2 yr old that always wants to climb up on the quad. So to prevent him from burning his hands and legs when he rides with me I wrapped the exhaust. I could not tell any difference in power after wrapping the exhaust. After you wash your quad a few times the black die in the wrap will wash out and the wrap will turn light gray. If your wanting your exhaust to be black and your wanting to hold in heat maybe you can put several coats of black powdercoat on the exhaust. I dont know if it will hold up or not but I am sure the powdercoating will hold in heat. Maybe this will help.

[TheNewn]

I figured i'd coat the wrap afterwards with high temp silicon spray. Keeps the dirt out of the wrap and i think that'll keep th e color in. I'll paint it first and see how it looks.

Thanks for the help everyone.