Controlling Underhood Heat on Turbocharged Cars

[derekf]

Ok, from this thread in the archives (it's the New, Improved, Twin Turbo Mule thread from the old site), I gather that twin turbo cars have an.. issue with underhood heat, and to deal with it things like:

stainless heat shields
Header coatings/wraps
heat shielded plug wires
some sort of shield to protect power steering hoses
additional oil capacity and oil cooling
and the obvious upgrades to the cooling system..

.. but what am I missing? Is there more that should really be done under the hood? Air ducts aimed at the turbos themselves (or is that a bad idea)? Anything else?

[camcojb]

According to Charley, he doesn't notice a lot of underhood heat like has been mentioned. I'm sure any kind of venting, heat shields, etc. will be beneficial, but I don't think it's quite as big of a problem as some think it is.

Jody

[Kenova]

About the only other thing I can think of is making an effort to vent heat out from under the hood. Punching some louvers in a low pressure area of the hood, behind the rad, would help a lot. I'm sure most people wouldn't find this a very attractive option though. I don't think I'd want to do it.
If a high quality thermal barrier is used on the exhaust components, I doubt that there would be too much heat to cope with.
Ken

[shmoov69]

Well......Underhood heat is a problem with mine. I haven't had too much problems, except when idling for long periods. Except on the PT this year, the engine did not like the timing with the gear what was in the rear going down the highway. EGT's were at about 1425*!!!! And for over an hour, that is pretty friggin' hot under hood!! But, that could be controlled with money on a F/I setup to set the timing where it needs to be. I do have the HPC super wonder coating good for 2000*+ on the headers and downpipes. I don't know if it helped much, but in theory it does! Heat sheilds would be nice to have, as well as underhood insulation, but not necessary, since mine doesn't. You must have a good radiator and fans tho. I melted a cheapie electric fan on the PT a few years ago in Detroit and the one I bought to replace it did not keep it cool at all, but the one I have now works ok, but it will start to get really hot if you idle longer than 20 minutes. And NOBODY will look at your car (underhood) up close for about 20 minutes when you park and open the hood! Stand back when you pop it or else you get your eyebrows singed! LOL!
The one thing I am constantly having troubles with is spark plug wires tho. I have (literally) cought 3 different wires (same hole) on fire from nothing more than radiant heat between the downpipe and valve cover (about 3"clearance). The wires need to be replaced somewhat frequently to keep it running good. I have the MSD wires with the black sheilding and super fat shielding on the bottom with the metal boot covers on them now on the car.
Jimmy

[TitoJones]

Wow. That is another reason I want to put my turbos down low like on a Lingenfelter C5. There is no chance of burning a wire with them low and out of sight, plus the under car air will help cool them a bit.Tyler