Wrapping headers?

[briansb]

Originally Posted by Heis-Strokanoff

holy canobe! Chemistry major in here? So wrapping the headers lowers the under hood temps, but is there an actual gain? i like my shiney headers

lol, M.S. and B.S. in Mechanical Engineering actually...

Wraping your headers has a couple of effects. By lowering underhood temps you reduce heat soak in your cooling system and other critical components. Higher ECT temps which will cause the ECU to retard the timing (or lead to more knock and possible detonation)

Additionally, wrapping headers can increase exhaust velocity and efficencies. I'll skip the equations this time - but by increasing the negative pressure wave which follows the exhaust pulse the scavenging effects will increase as the air inside the combustion chamber will be pulled into the lower pressure wave in the headers/exhaust. This is also why wave or hemoltz tuning can be so critical and choosing headers that have a proper primary design and merge collector system is so important.

[briansb]

Aditionally - if you want them to look nice/shiny and still gain the effects pull them and have them coated. There are a varity of coatings out there that will have better thermal effects than wrapping and looks much better, in my opinion.

Most reliable after market exhaust systems offer headers with a ceramic coating. The borsol system we have in my brothers car is coated all the way through the downpipe. The coating ALSO keeps the headers from corroding and discoloring like uncoated headers are prone to doing.

[Heis-Strokanoff]

Well with all this brainy talk, i just might nickname briansb " The Brain " and go wrap up my headers or atleast the front header