Is there anyway to make the hood vents in T\A's work like ram air? if not then what exactly do they do? i notice that they seem to direct air infront of maybe the radiator?

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- David
88' GTA 5.7L TPI MODS---> air foil, K&N, Shift Kit, 180* therm, TB bypass, Gutted CAT, Flowmaster 80 Series

 

The vents in the hood are just for looks. They have no functional purpose. I am currently throwing arround some ideas to make the vents functional. I don't know how but I will figure something out.

 

know if u look under the hood, u can see some light where they come through, at least on mine u can, but it looks like they have no purpose, might be easier to do somethign with em if u had speed density set up.

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- David
88' GTA 5.7L TPI MODS---> air foil, K&N, Shift Kit, 180* therm, TB bypass, Gutted CAT, Flowmaster 80 Series

 

The holes in the bottom of the vents is about 1 1/4 inches and are there for some reason but the vents are not functional. I am thinking of building boxes on the bottom side of the hood and making a setup with the filters from a tpi camaro and bolting the bottom part of the assy to the upper radiator support. I don't know how much clearance I might have in between the hood and the upper radiator support. This is just a possiable way but I want to find a hood from a trans am just to experiment with so as not to screw up my hood.

 

the holes are so you can get a socket in and take the louvers off.

 

Actually the holes are air extractors, thats what pontiac calls them anyway. They gointo the hood in front to circulate cool air the the hot air comes out of the slits in the rear.

 

I don't beleve the extractors actually work. Look at the holes in them they are so small they could not possiabally help. The front ones are not going to pass any air as compaired to the air that comes into the radiator.

 

ya, turn on ur a\c or wait until ur radiator fans come on, and feel around the vents, NO air comes out at all, it all goes under the car. but i bet they could be changed to work better for some purpose.

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- David
88' GTA 5.7L TPI MODS---> air foil, K&N, Shift Kit, 180* therm, TB bypass, Gutted CAT, Flowmaster 80 Series

http://www.geocities.com/david_angel_16

 

Definately all cosmetic in design. If the hood blanket and the foam pieces in the rear "extractor" vents are removed, some air will be pulled out of those vents at speed, all-be-it not enough to mention. The vents on the front of the hood are virtually useless as the area directly behind them when the hood is shut is disrupted by the radiator shroud which is about a 1/4 inch from the underside of the hood when it is closed, making any attempt to make a Ram Air system out of them, virtually impossible. Not to mention that a lot of cutting of the underhood structure would have to be made to open up the area behind the vents to get any useable volume of air to enter the underhood area. In stock form, they let a small amount of outside air in between the hood structure and outer skin through those vents - keeps the hood a touch cooler but I doubt anything else.

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1987 GTA L98 MD8
355, TFS Heads, LT4 Hot Cam
My GTA

The Minnesota F-body Club

 

purging your Nitrous through the vents is a effective use.

 

Corey,

Your answer was most correct. The purpose of the extractors (on the sides of the hood toward the rear) are to divert air from the high pressure area of the cowl and relieve high pressure at the nose of the car. The air at the curve of the front portion of the hood (where the intakes are located) is partially routed through the vents. The air exiting the rear "extractors" is supposed to deflect toward the sides of the windshield and help divert air from the higher pressure area at the base of the windshield.

The entire system would be a lot more functional without the stainess screens mounted behind the vents, but they still provide some relief for the pressure at the front of the hood.

If you remove the hood insulation blanket and study the inner hood stiffener, you'll see that the air vents at the front are ducted through the stampings to the vents at the rear.

It's about as close to functional aerodynamics as GM ever got in a production car. The 1986-1988 rear wing spoiler was also a functional piece, although too small to be completely effective. Subsequent years' spoilers were typically cosmetic only, and provided no effective downforce at the rear of the vehicle - some of them actually cost handling forces instead of contributing positively.

The side air skirts and effects are far too small on a car at stock height to be effective, and are basically cosmetic. You can lower the car and install longer skirts to get some really low pressure under the car, but it will cost you a little top speed as well. The vented hood should actually contribute a bit to top speed and aerodynamic stability over 120 MPH.

All said, they are functional, but really don't do as much as they could. The theory was sound, but mass production and practical application made them almost useless.

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Later,
Vader
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Justice and Freedom will Prevail
Adobe Acrobat Reader

 

Actually, I think mine was closer.

 

woops! I was talking bout the circular holes about 1 1/4 inch on the bottom of the HOOD that let you get to the nuts that hold the front louvers on. Vader's right on about the extractors though.

 

I looked into this, and even with both holes opened up and the screens for the vents taken out (you would have to for any improvement at all) the air still has an extremely small opening to pass through, barely bigger than the stock mail slot or circle depending on your stock setup. The only possible advantage would be the cold air from outside of the car, but thats about it with the factory hood vents and then you gotta cut up your hood to do it.
Definitely measure first a few times and take the vents and screens into consideration before you start cutting.

Vader, that spoiler was used from 85-90.

[This message has been edited by madmax (edited October 10, 2001).]