Extraction above exhaust manifold
 

Hello all,
Got a big problem with heat in the engine bay when im on the throttle for any period of time. Ive got the mini scoop on the hood behind the rad and that works well, my issue is purely manifold heat related, to the point where it makes the paint on the underside of the hood tacky after a long run. I dont want to wrap the manifold beacuse a) it looks great b) it would be an a-hole to do and c) its stainless so would probably crack quicker.
I want to know if anyone has used an extraction vent above the manifold to pull this super heated air out of the engine bay. Judging by past posts on the pressure differential on the hood it looks like there is little difference above and below the hood in the turbo area and hence i assume little extraction effort.
Does anyone have any first had experiance ? Fabricating a vent is not an issue, i just dont want to cut a great big hole in the hood for it not to work. It would be in the area you can just see at the top of this image (where i have refelctive heat mat fitted) and maybe a little forward of this - but it is worryingly near the back of the hood !
http://www.total-gtr.co.uk/upload/images/DSC00407.jpg

Wrapping the manifold is a band aid at best. Real heat shields and a vent will help significantly. There's a 'custom hood vent' thread around here some place with anecdotal data.

Nice looking engine bay. Very clean.

What about heat shielding?
I doubt a vent will help you out. Also if you do manage to cool it off effectively that't not exactly great for the manifold, and keeping it cool will slow your spool time and rob it of energy needed to get that turbo huffin and puffin.

DEI Tunnel Matt is awesome. I use it on my fiberglass hood. I can race the car for 30-minutes, then sit in "park firme" for 15 minutes for weight and legality checks and it doesn't screw up the fiberglass hood.

I would think you would have to use a vent with something to cause turbulence to pull the air out through the opening in the hood.

I think a better solution would be a heat shield that attaches to your manifold bolts or valve cover bolts and goes over the turbo would be superior in every way.

If there is a hole in your hood it is a direct entry for water so then you'd have to not drive it in the rain/devise a way to channel the water away from the turbo/manifold.

wrong thread. I'm homosexual.

No problem?

Shield what you dont want to be hot and not the turbo. The tunnel matt stuff that Trey was talking about should be the simplest and the most correct way to go about this.

You could probably make a decent looking shield attached to the hood with a slight air gap. I had used a cookie sheet attached by snaking nuts behind four of the holes in the hood frame with studs and locking nut from below.

I am sure with a little effort, something like this would work and leave your turbo area as it is.

If you're going to go with a stick on shield, DEI Reflect-a-gold is far and away the best stuff on the market. It's pricey, but worth it in every way. Don't put it on anything you don't want it to be on forever, though. The adhesive is sticky as heck and super temperature resistant.

Ceramic coat your header inside and out. I have a guy that does VERY robust coatings. They will lessen the heat quite a bit. I wrap my downpipes, and seal them with silicone heat wrap spray. Keeps water out of the wrap.

The gold stuff is good, but I've used both and tunnel mat is exponentially better.

I'm really surprised to see that. I'll have to look into it. My experience has been that the gold stuff is lightyears ahead of anything I've replaced with it.