I want to try a different hood scoop......

[coloradodave]

Quote Originally Posted by coloradodave View Post

If we're actually talking about going faster, not what LOOKS good, take a page from the Mopar engineers: that is, use a scoop that you can seal to the carburetor airhorns. According to the direct connection manual, if the scoop isn't sealed to the carbs, it's not helping, and possibly hurting your ETs, by not having "smooth" air across the airhorns.
I ran a C/Gas Corvette years ago with an all out 331" small block and a tunnel ram with 660 Holleys. Just by sealing the carbs to the scoop I picked up 4 tenths. Nothing to sneeze at...

I don't have enough room above to seal the carbs.



Have you seen the Harwood Aero scoops?

 

[SUPERSTOCKRACER]

Quote Originally Posted by coloradodave View Post

If we're actually talking about going faster, not what LOOKS good, take a page from the Mopar engineers: that is, use a scoop that you can seal to the carburetor airhorns. According to the direct connection manual, if the scoop isn't sealed to the carbs, it's not helping, and possibly hurting your ETs, by not having "smooth" air across the airhorns.
I ran a C/Gas Corvette years ago with an all out 331" small block and a tunnel ram with 660 Holleys. Just by sealing the carbs to the scoop I picked up 4 tenths. Nothing to sneeze at...

I don't have enough room above to seal the carbs.



Have you seen the Harwood Aero scoops?

Yes and I like them a lot.
What do you think open back or closed back?

 

[dvw]

Block the font of the scoop and remove the inner headlights. I work with a guy that runs All Motor at Milan w/69 Camaro. It has had many many different cowl and air pan set ups. Some work OK, not great. Some are bad. C
ar is no stone 8.30s

 

[SUPERSTOCKRACER]

Block the font of the scoop and remove the inner headlights. I work with a guy that runs All Motor at Milan w/69 Camaro. It has had many many different cowl and air pan set ups. Some work OK, not great. Some are bad. C
ar is no stone 8.30s

The front grille is blocked off and the inner headlights are removed.
You want me to block off the front of the scoop?

 

[dvw]

Duct the air through the core support to the carbs. Like a Thunderbolt. It will definitely take some core support mods. But certainly will have high pressure air flow with no aero penalty. The scoop only needs to be there to cover the carbs due to height. Therefore the front can be sealed.
Doug

 

[wannadrag]

I never really got the cowl hood. is it a venturi-type effect?

I would think facing the wind would be more efficient.

Mar,think about how much air on these old cars comes in when you open the vent inside the car.Cowl induction works the same and sucks up all that air also.Many of my old GM drag cars I would just take a 2" hole saw and put a few holes in the cowl so the outside air would be sucked into the engine compartment and never used a scoop.

 

[HawkRod]

Mar,think about how much air on these old cars comes in when you open the vent inside the car.Cowl induction works the same and sucks up all that air also.Many of my old GM drag cars I would just take a 2" hole saw and put a few holes in the cowl so the outside air would be sucked into the engine compartment and never used a scoop.

The air just above a hood of a car actually does not move very well. Like my air grabber, for instance. It looks cool as hell (in my opinion), but the air just above the hood really does not help ram any air in. Yes, you get cold air and it does help, but not a great deal. If you look at professional drag cars the scoop sits high above the hood to avoid this problem. Another way to think about it is to imagine a stream. The water near the edges barely moves, while the water in the center moves the fastest. The same thing happens with air.

With cowl induction, the windshield provides a high pressure area that helps push air into openings at the base, be they for vents into the car or air into the carb. Cowl induction is an awesome setup based on physics that works great...

 

[69RRGTX]

Put a cowl hood on it, that would be the quickest and easiest solution. Especially since you are doing this to a second hood. If you want a carb air pan to work go with a smaller pro stock style.

 

[MarPar]

Mar,think about how much air on these old cars comes in when you open the vent inside the car.Cowl induction works the same and sucks up all that air also.Many of my old GM drag cars I would just take a 2" hole saw and put a few holes in the cowl so the outside air would be sucked into the engine compartment and never used a scoop.

Za! thanks Jay!

The air just above a hood of a car actually does not move very well. Like my air grabber, for instance. It looks cool as hell (in my opinion), but the air just above the hood really does not help ram any air in. Yes, you get cold air and it does help, but not a great deal. If you look at professional drag cars the scoop sits high above the hood to avoid this problem. Another way to think about it is to imagine a stream. The water near the edges barely moves, while the water in the center moves the fastest. The same thing happens with air.

With cowl induction, the windshield provides a high pressure area that helps push air into openings at the base, be they for vents into the car or air into the carb. Cowl induction is an awesome setup based on physics that works great...

makes sense Hawk!

thanks for helping out a noob guys! :sSig_noob:

and now back to our regularly scheduled programming...:happy1:

 

[Roughbird72]

I like the aero scoops. But I see a lot of fast cars going to the cowl hood. There's got to be a reason.

Yes, there are a LOT of cars with the cowl hood.i believe the Cowl would have less drag & the high pressure air at the base of the windshield works ... some cars look good with a cowl & some don't.

 

[SUPERSTOCKRACER]

theres got to be a reason the prostock guys use the aero style scoops compared to a cowl hood?

 

[mmissile]

Same principle as what you have....only more controlled and directed. I think someone is playing dumb here.

 

[Cranky]

How bout one of these? The car was still pulling pretty good at the stripe with this scoop....

I would think the rake of the windshield plays into how well a cowl induction scoop works is why the present day Pro Stocks don't use a CI hood scoop? Also, a ram air intake can and usually does work better than a CI setup. A proper ram-air setup can be up to 25 percent more efficient than a cowl induction hood and may actually generate as much as 2 to 3 psi of boost at very high speed. How high of speed that it makes that kind of boost depends on how well the setup is done....and the only way to tell how much it's producing is to use test instruments on an actual run. I've never been a fan of CI scoops either and it seems that the ram air systems have been gaining popularity over the years but you would still need to cover the carbs with something with a RA system.

 

[mopar12372]

A buddy of mine races stock / superstock with a huge scoop, raised the back of the hood so air will get out

 

[HT413]

Seems to me most times I see cowls, they're on turbo or centrifugal supercharger cars just to provide clearance and allow excess hot air to escape. So if you don't have room to seal the carbs to the scoop, I think a cowl will slow you down dramatically, as the cowl will be an EXIT only.

- - - Updated - - -

...may actually generate as much as 2 to 3 psi of boost at very high speed. How high of speed that it makes that kind of boost depends on how well the setup is done....

I think this is a great point, but if you don't seal the carbs properly, any pressure differential will be dispersed into the engine compartment instead of into the intake.

 

[Roughbird72]

I think this is a great point, but if you don't seal the carbs properly, any pressure differential will be dispersed into the engine compartment instead of into the intake.[/QUOTE]

agree 100%

 

[SUPERSTOCKRACER]

I think someone is playing dumb here.

Please elaborate.

 

[coloradodave]

The reason Pro-Stock guys run the aero scoops is because they have access to the factory wind tunnels for testing. Copying them is GOOD. I always ran my scoops with the back end open. Thinking that closed is just creating a lot of turbulence and drag.

 

[SUPERSTOCKRACER]

The reason Pro-Stock guys run the aero scoops is because they have access to the factory wind tunnels for testing. Copying them is GOOD. I always ran my scoops with the back end open. Thinking that closed is just creating a lot of turbulence and drag.

Looking at the cowl style it seems to make sense that aerodynamics is better compared to a hole in the front of the car.
Anyone else agree?

 

[actionange1]

NASCAR uses cowl induction exclusively forever. However they direct all the air into the throttle body thru air box taking the air from the base of the windshield and much lower profile than a tunnel ram intake.
You would need a pretty tall cowl hood to cover your carbs.

And they pretty much block off the entire nose for aero. Just a small area for cool air to the radiator.
Just my 2 cents...