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Old 01-29-2015, 10:26 AM   #1
targus
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Default Cowl Hood vs Snorkel Scoop

I currently have a forward facing snorkel scoop on a 68 camaro. The car currently runs 9.30s and the hood has an air pan sealing it to the carb. Currently there is approximately 1.5" of clearance from the carb to the top of the scoop. We are debating putting a 6" cowl hood on, just for looks but i am now questioning the performance difference that it could make.

So my questions are, what are the differences that you have seen between cowl induction hoods and forward facing scoops?

Also, what is the difference between the older square style snorkel scoops and the newer aeroscoops?
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Old 01-30-2015, 01:47 PM   #2
Jim Caughlin
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Default Re: Cowl Hood vs Snorkel Scoop

Anything less than 2" top of carb to bottom of scoop clearance will affect performance, this has been proven on dynos.

In my case, just removing the seal between the carb and the front facing hoodscoop slows the car by almost a tenth.

In the case of Stockers that have cowl hoods, they have been proven to have zero performance gain over a flat hood even when the carb is sealed to the scoop. They effectively are no more than a carb cover.

I don't care for the looks of front opening snorkel hoodscoops but there is no question that they are the best for performance.

Jim Caughlin
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Old 03-01-2015, 08:37 PM   #3
Eric Crawford
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Default Re: Cowl Hood vs Snorkel Scoop

Quote:
Originally Posted by Jim Caughlin View Post
Anything less than 2" top of carb to bottom of scoop clearance will affect performance, this has been proven on dynos.

In my case, just removing the seal between the carb and the front facing hoodscoop slows the car by almost a tenth.

In the case of Stockers that have cowl hoods, they have been proven to have zero performance gain over a flat hood even when the carb is sealed to the scoop. They effectively are no more than a carb cover.

I don't care for the looks of front opening snorkel hoodscoops but there is no question that they are the best for performance.

Jim Caughlin
SS 6019
That's good to know. I was thinking of putting the air pan back on my car when it gets back together. (Cowl hood) I may not even worry about it now.
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Old 07-28-2015, 09:00 AM   #4
oneowner73
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Default Re: Cowl Hood vs Snorkel Scoop

If your cowl extends very close to your windshield you will be in a high pressure area created by the air turning up the windshield. Changing directions causes resistance creating pressure. If your cowl is too far from the windshield it works like a draw tube like header evac systems. I went from no air box with my 6" cowl to an unsealed box and ran the same et and 1 mph faster in 1000' worse air in the 1/8 mile.
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Old 07-28-2015, 06:13 PM   #5
RON NICKELS
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Default Re: Cowl Hood vs Snorkel Scoop

If cowl hood scoops worked better than a frt. air scoops ,pro stock cars would be running a cowl hood lol.
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Old 07-28-2015, 09:25 PM   #6
Bill Baer
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Default Re: Cowl Hood vs Snorkel Scoop

"but there is no question that they (snorkel scoops) are the best for performance." Yep.

Neither will work well unless you seal the scoop to the carb there's a ton of hot air coming thru the radiator.
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Last edited by Bill Baer; 07-28-2015 at 09:29 PM.
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Old 07-29-2015, 04:09 PM   #7
voltdr
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Default Re: Cowl Hood vs Snorkel Scoop

Unless your MPH is near or above 150, Then the snorkel scoop doesn't care where it gets its air from, front or rear. The performance increase comes from the cooler intake air versus the engine heated intake air. With most cars, there is such a wall of air you're pushing in front of the car it doesn't know the difference. As long as there isn't a vacuum created by the aero package.
Dan
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Old 05-13-2017, 06:58 AM   #8
StickBBF
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Default Re: Cowl Hood vs Snorkel Scoop

Yeah, this is an old thread, but racing season is here again and it's starting to get warm.... so it's something to discuss once more.

Quote:
Originally Posted by Bill Baer View Post
.... there's a ton of hot air coming thru the radiator.
EXACTLY! And hot air is NOT what you want.
In contrast, however, would the non-scooped, underhood air temps likely be less variable? From 3PM to 10PM, outside air temps can vary greatly coming in the scoop. It seems to me that less variable intake air temperatures would equate to less jet changes and be a more consistent overall air/fuel mixture, correct?

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Old 05-14-2017, 10:15 PM   #9
Marc
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Default Re: Cowl Hood vs Snorkel Scoop

Quote:
Originally Posted by StickBBF View Post
Yeah, this is an old thread, but racing season is here again and it's starting to get warm.... so it's something to discuss once more.



EXACTLY! And hot air is NOT what you want.
In contrast, however, would the non-scooped, underhood air temps likely be less variable? From 3PM to 10PM, outside air temps can vary greatly coming in the scoop. It seems to me that less variable intake air temperatures would equate to less jet changes and be a more consistent overall air/fuel mixture, correct?

StickBBF
My good racing friend and owner of a racing school would agree with you 100%. He is a big advocate of flat hoods and even recommends those with forward facing scoops to seal them off to improve consistent underhood air temps.
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