header wrap, or cermaic coating?

[sfwilliams@comcast.net (Scott F. Williams)]

Ryan H. wrote:
> I'm not sure there would be many advantages with either, other
> than keeping some of the heat out of the engine bay...

That's an advantage that pays dividends on several levels. First of all, it
keep the heat in the exhaust. This maintains the exhaust gas velocity which
means greater flow/horsepower. Secondly, it keeps the heat out of the engine
bay like you said. That means that the intake manifold won't be heat soaked
as readily. The intake charge will be denser which, again, contributes to
generating more power.

The question is, how much power will be gained for these reasons? And, will
the gains be worth the investment? On a carbed (non-crossflow) 8v, I'd
definitely think so. On a turbo'd anything, I'd also consider it a
no-brainer. A header also radiates more heat than a cast iron manifold. So,
perhaps any engine with such an exhaust would benefit? What I do know is
that you lose about 1hp for every 10degF increase in underhood temperature.
--
Scott F. Williams
NJ Scirocco nut
'99 Subaru Impreza 2.5 RS
Mazda 323 GTX turbo "assaulted" vehicle
Golf GTI 16v "rollycar"
ClubVAC: "Roads found. Drivers wanted."