Functionality of the Old Stingray Hood scoop

[Johnny Blaze]

I'm thinking about putting one of the scoops on my 71, ala Gumball Rally, but was wondering how they work.

http://www.speedwaymotors.com/Stingray-Corvette-Style-Fiberglass-Hood-Scoop,6170.html


Its basically a cowl induction scoop, with the front cut open.

They say "allows air to enter from the front and rear of the scoop"


Wouldn't the air just flow straight through it?

If the carb was sealed to the hood, would air flow right over it, and cause more harm then good?

Or is air still forcing its way in the back via the cowl?

[MonzaRacer]

Actually they didnt do bad in allowing cool air in if sealed to carb. Kind of like when people used to say old snorkels, then it was found if they added a lip, like 30 or 45 deg around opening it picked up EVEN MORE air. Heck even the newer aero snorkels help in air flow.
BUT biggest reason is to pick COOL air. Knock 10 deg off intake, 1 to 5 % more power. From what I have read, get air from a high pressure areas like base of windshield its does even better. Ever see the old Camaros ducted to the cowl area,,, high pressure area caused by windshield blocking air flow over hood and air piles up. Also if just ducted to engine compartment cowl hoods in some cars can help on front end rise at higher speeds, kind of like the naca ducts and vents on Trans Ams and similar cars. Some pull hot air away from brakes but also help create negative air pressure inside engine compartment,,,to a point.

[TonyHuntimer]

The open front would probably pull air in, but not as much as the back (ala cowl induction) at the base of the windshield. The only way cowl induction hoods actually work as cowl induction...is to seal the hood against the air cleaner like the factory did.

71166

If you sealed the front to the top of the carb, it would be forced to ram air into the carb. The opening at the back of the hood would allow hot air trapped under the hood to escape the engine compartment.

If you're running a hood with an exit at the rear, you'll get hot air and fumes from the engine compartment in the windows of the car. Not cool. I did it for years. I wish I had spent the extra dough for a sealed unit. I will next time I use a cowl hood.

Tony Huntimer
TonysSpeedShop.com



I'm thinking about putting one of the scoops on my 71, ala Gumball Rally, but was wondering how they work.

http://www.speedwaymotors.com/Stingray-Corvette-Style-Fiberglass-Hood-Scoop,6170.html


Its basically a cowl induction scoop, with the front cut open.

They say "allows air to enter from the front and rear of the scoop"


Wouldn't the air just flow straight through it?

If the carb was sealed to the hood, would air flow right over it, and cause more harm then good?

Or is air still forcing its way in the back via the cowl?

[Tom Welch]

I bet that air flow testing would show that the opening has negative pressure if not sealed to the carb and if so there would be almost neutral pressure. I believe that the airflow would go over the scoop more than into it because its too low on the hood to catch much due to the boundary layer of air that is about 1-2 inches high. On my first Firebird, a 67, (a 400 car) I noticed that coolant was running out of the driver side hood scoop going forward on the hood as I drove the car when it ran hot one time, the carb wasnt sealed to the hood. The higher pressure from the air flowing into the engine compartment from the front of the car completely negated any benefit that the hood scoops may have provided.

[Johnny Blaze]

The thing about this scoop, is that is open in the front as seen in the pic, but it is also open in the rear.

This was a factory vette design but was only used one year, IIRC.

So you have air coming in the front opening, and in theroy, air coming in the rear ala cowl induction.

I would think air would just go in the front and right out the rear.