Header wrap question

[SMEGMA STENCH]

I have a dumb header wrap question for yall. I'm not much of a gearhead so I don't know shit like this. But it occurs to me, that if you are using header wrap on your headers, that heat isn't transferring through the header walls so it must be going somewhere else. It must be going down the exhaust pipe at least a little ways before it starts soaking through.

So my question is this: Is it possible to see negative side effects from this? I mean after all, if all that heat isn't going out the normal way, it is going somewhere. Where might that be? Can it lead to needing to replace your exhaust pipe sooner? Could the extra heat (that would normally not be there) soak through and harm something else that is not near the engine? I was considering using some header wrap but I was wondering if there are any drawbacks.

[slow55]

The only drawback to header wrap is that it looks like shit.
Other than that it works great and does help reeduce heat in the engine bay. Won't effect anything else in the exhaust system.

[stevo]

Hedman says that using header wrap voids their warranty because it causes the tubing to overheat which causes metal fatigue, at least that is what was on the instructions that came with the headers. It might be bullshit though.

Stevo

[SMEGMA STENCH]

The only drawback to header wrap is that it looks like shit.
Other than that it works great and does help reeduce heat in the engine bay. Won't effect anything else in the exhaust system.

At the very least it has to heat up the floorboards... or does it? You would think that since the heat will now be much closer to the pedals, you'd feel it.

[scootro]

It cost more but why not use a Thermo-Tec Header Blanket it's definitely old school technology but it works. Check out Thermo-Tec's website they have all kinds of cool shit on there.

[Trick Pony]

Actually, according to thermodynamics keeping the heat in the exhaust flow and having it exit out the tips instead of through the pipe means more efficiency and more hp.

[Strychnine]

Hedman says that using header wrap voids their warranty because it causes the tubing to overheat which causes metal fatigue, at least that is what was on the instructions that came with the headers. It might be bullshit though.

Stevo

Sounds about right. Here's another take on it. In most cases wrapping the exhaust pipe is fine but wrapping the manifold and/or turbo is not allowed.

The use of exhaust blankets on exhaust manifolds and turbochargers leads to increased temperature of exhaust manifolds and turbocharger. These increased temperatures cause a decrease in the material strength of the turbocharger and exhaust manifold, which can lead to exhaust system failures.

Scaling of the exhaust manifold can also occur at the higher temperatures associated with blanketing exhaust manifolds and turbochargers. The scaling is caused by oxidation of the manifold, which occurs at an accelerated rate at temperatures above the material design limit

The increased exhaust manifold and turbocharger temperature
s associated with the use of exhaust blankets increases the thermal stresses on the components. This significantly lowers the useful life of these components and increases the risk of failure due to cracking.

Figure 2 illustrates the damage caused by blanketing a turbocharger, without power derate, in high load factor application.

Actually, according to thermodynamics keeping the heat in the exhaust flow and having it exit out the tips instead of through the pipe means more efficiency and more hp.

How do you figure? Internal combustion engines are just that... internal. Heat is energy, and the combustion energy acts on the piston to move the crank. Once the energy has left the combustion chamber (whether to the piston, the coolant or the exhaust) you can no longer create power (unless you have a way to capture that heat ie. turbocharger).



EDIT:
Keeping heat inthe exhaust gas will keep the flow rate higher, in theory helping to move the gas out faster (slightly decreasing backpressure), but the typical heat rejection through the exhaust pipe wall is 20*F/ft, (+/- 10*F on the total) depending on ambient temp, load, material, etc. Is it really worth the trouble for such a minor improvement though?

[KBScobravert]

I know that in turbo applications the more of the exhaust heat you can keep INSIDE the pipes the more efficient the turbo will operate.

Using a colored wrap (black) and done right does not look bad.

[scootro]

.....

is his car turbocharged?

[Strychnine]

is his car turbocharged?

Whose car? The OP is generalizing.

[SMEGMA STENCH]

The use of exhaust blankets on exhaust manifolds and turbochargers leads to increased temperature of exhaust manifolds and turbocharger. These increased temperatures cause a decrease in the material strength of the turbocharger and exhaust manifold, which can lead to exhaust system failures.

Scaling of the exhaust manifold can also occur at the higher temperatures associated with blanketing exhaust manifolds and turbochargers. The scaling is caused by oxidation of the manifold, which occurs at an accelerated rate at temperatures above the material design limit.

This is what was concerning me. I'd certainly like whatever gains I can get from header wrap, but it just seems like its going to kill the headers sooner than they should die. Then again if that takes 10 years, who really cares.

is his car turbocharged?

No it is not. I just wanted to know in regards to wrapping the manifolds themselves.

[KBScobravert]

Non turbo application just get a good ceramic coating on them.


Turbo you want to have the DP, cross over and merge wrapped. A lot of turbo kit makers will tell you that wrapping their headers will void warranty but for me mine will be wrapped. Anything I can do to keep the temps down under the hood is my approach. If my headers start to crack or get leaks I will get them fixed and just rewrap again.

[scootro]

This is what was concerning me. I'd certainly like whatever gains I can get from header wrap, but it just seems like its going to kill the headers sooner than they should die. Then again if that takes 10 years, who really cares.



No it is not. I just wanted to know in regards to wrapping the manifolds themselves.

oh ok i was just wondering!

[mdavis]

ceramic....gooood wrap.....baaad

[SMEGMA STENCH]

Non turbo application just get a good ceramic coating on them.


Turbo you want to have the DP, cross over and merge wrapped. A lot of turbo kit makers will tell you that wrapping their headers will void warranty but for me mine will be wrapped. Anything I can do to keep the temps down under the hood is my approach. If my headers start to crack or get leaks I will get them fixed and just rewrap again.

Yeah see I'm a noob cause I didn't know ceramic actually did that. I thought it was just what you had to have if you wanted your headers to keep the color that you bought them with. Seeing as how you'd need like space shuttle paint to keep them from turning to rust. So just to confirm, ceramic coated headers force the heat to go out instead of soaking the engine bay? How well does the ceramic work vs wrap? Or... what if you wrapped ceramic! lol