Question about the function of a cowl hood

**Warbird** · 11-13-2006, 03:25 PM

just have a general question about cowl hoods. I know that when the car is driving down the road/track, as air passes over the cowl and hits the windshield, the air gets sucked into the engine bay. Is that the only function of a cowl hood, or does it let the hot engine bay air out? And I'm guessing it would only let it out when the car is motionless and not moving.

**Orcus79** · 11-13-2006, 04:02 PM

Air induction only, a properly installed one will be sealed from the engine bay.

**chevyguy8413** · 11-13-2006, 04:54 PM

The properly located cowl air intake is in a high pressure area (contrary to many centrally located scoops) and actually experiences slight pressure boost as a result. Other provisions may be made to exhaust hot air from the underhood area, which is just as important. Other good locations for air intakes are in the grille area or jst below the bumper.

**Y2KPewterSS** · 11-13-2006, 05:30 PM

Moved from appearance forum to help get better attention.

**Steve Crowe** · 11-13-2006, 05:34 PM

It's not so much the slight positive pressure that can build in that area (which is highly dependent on the windshield angle and front end aerodynamics, sometimes it's negative) but more because that's an area cooler air will prevail.

**chevyguy8413** · 11-13-2006, 06:01 PM

good points...all..thanx

**chevyguy8413** · 11-14-2006, 06:26 AM

Originally Posted by Y2KPewterSS

Moved from appearance forum to help get better attention.

Awsome ride man...you're about where I would like to be in say..a year or so...if I can find a really pristine LS...not necessarily SS like yours....

**00vertss** · 11-16-2006, 04:53 AM

Not a 4th gen,but on my 3rd gen. Formula I took the plastic piece from the bulge hood on the back side. I installed a screen for looks and I can see the hot air or waves come out. I dont know about it being a cowl but a mini cowl maybe. All I see is the heat getting out which works for me.

**chevyguy8413** · 11-16-2006, 09:19 AM

now thats what i call being creative....good show...letting bad air out is just as important as good air in..

the 63-65 Ford fiberglass hoods for drag racing had "hot air exit" hoods, and drew fresh air in from the very front of the car thru flexible hosing..either in the "faux" headlight opening or under the bumper; Mercury Comets had scoops in the hood but they were at the very leading edge of the hood where they caught clean air flow.

**Steve Crowe** · 11-17-2006, 07:29 PM

Very sound thinking which is (no offense intended) unlike Ford.

Pulling the heat from your underhood helps the entire intake path to be cooler. The main enemy that we have control over is the radiator, and if one could get that air out of the engine bay ASAP we'd all benefit.

Comes to mind a discussion started long ago in another forum, under chassis aerodynamics and the gains from this forgotten area.

**Warbird** · 11-17-2006, 08:02 PM

Getting the radiator air out of the engine bay wouldn't be a problem. You would just have to use a heat extracter scoop at the bottom of the hood, like a lot of aftermarket import hoods have. Universal extractor scoops can be found anywhere [ebay].

**Steve Crowe** · 11-17-2006, 08:42 PM

Yes, but one could find a true advantage in getting that hot air out the lower side as opposed to it going over the intake areas.

Didn't some of the original Trans Am side scoops aim at this?