How does a hood scoop work?

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'74 Sport

'74 Sport

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This is for those of you who have a functional hood scoop...

What keeps water from getting sucked up into the carb? I understand the concept of drawing colder, denser air into the carb. But, if you are driving along at 65 mph in a downpour, wouldn't the rain blow right into the scoop and get sucked in through the air cleaner (especially an open-element breather)?

We're not sure of the hood clearance on Aaron's Duster, until we can get the 360 installed. If it is too tall (Mopar M1 intake, 1" spacer, Holley 4bbl, Mopar open-element breather), we will have to cut out the hood and install a scoop. Aaron's Dart Sport has the twin snorkel scoop, but it is just for appearance, not for function.

Jerry
 
I am somewhat familiar with the shaker hood. In that situation, air enters the intake with a ram effect, which increases with increasing speed. The shaker is a closed system. The lower plate has a rain baffle that keeps driven rain from soaking the front of the filter. Puddling water on the lower plate is drained off through rubber tubes that dump to the ground below. The filter element is actually elevated slightly higher than this rain "gutter" in the lower plate.
 
FISHBREATH said:
I am somewhat familiar with the shaker hood. In that situation, air enters the intake with a ram effect, which increases with increasing speed. The shaker is a closed system. The lower plate has a rain baffle that keeps driven rain from soaking the front of the filter. Puddling water on the lower plate is drained off through rubber tubes that dump to the ground below. The filter element is actually elevated slightly higher than this rain "gutter" in the lower plate.
Click to expand...

That makes sense, I guess, but the Duster won't have a shaker hood, it would need to be similar to the twin snorkel, six pack, or max wedge style scoops popular on these model cars.

Do any of you have factory scoops of these styles, where you can provide some photos?

Jerry
 
Convertriple 73 said:
http://www.forabodiesonly.com/mopar/showthread.php?t=14058

Hi Jerry,

The link above should provide some insight on this for you should you decide to go with a dual snorkel scoop on Aaron's Duster. As far as hood clearance, you may want to consider purchasing an air cleaner base plate with an 1" or so drop for added hood clearance.
Click to expand...

Thanks for the link, Bill. Lots of good info, but still doesn't answer the burning question about how to deflect, or otherwise prevent, any rain from entering the filter element. Aaron already bought the Mopar Performance cast aluminum filter element housing, so the lowered base plate isn't an option.

Time to get creative...
Jerry
 
OK. The Hemi scoop was designed as a race only unit. No baffles, no nothing. They did not race in the rain.

You could start with a fresh air-type filter housing, such as from an Air Grabber Roadrunner or GTX (I believe they are being re-popped again). This unit would have the thick foam rubber band that seals the base plate to the hood-mounted mating plate.

Or, you could fabricate something from an old giant base plate from a C-body. The question remains whether you want ram air effect. If you do, you will have to "box in" the filter unit to the hood so that all incoming air goes to the filter/carb and not mix with hot underhood air, which, by the way, is somewhat pressurized under speed. This was not a concern with race cars because they got to effective ram air speed fairly quickly, which overwhelmed the under hood pressure.

On a street car with the Hemi scoop, because of the huge opening of the scoop, not only will you scoop falling rain, but water on the hood will be pushed into the opening. Look at how water travels along your present hood in a rain storm to get the idea. If you want to use the Hemi scoop on a street car, you might want to create a curb on the hood around the hood cut-out to direct water away from the hole and through vents on the side lower edges of the scoop.

For street driving, if you want to do minimal fabrication, go with the snorkel. At least you won't have the water running into the engine compartment from the hood deck.

Just my opinion and some ideas to work with.
 
I ran an open dual snorkel scoop on the street for about three years on a daily driver (I also had fenderwell headers). This was in Kansas, rain, snow, whatever, the car was my only transportation besides a motorcycle. The engine wasn't sealed to the bottom of the hood, I just had a 14" open paper-element air cleaner under the scoop. I only plugged the the hole in the hood once. It was the middle of January & my Mom & I were making a highway trip of about 210 miles each way. Too much cold air was coming through the firewall somewhere & the heater couldn't keep up. I stopped at a rest area & shoved a piece of cardboard into the scoop to keep some of the cold air from coming through. Other than that one time, I never closed off the scoop & I never had a problem.
 
My Demon scopp was always open, feeding the top load K & N........really helped the breathing........and it COOLED the passenger compartment, like the previous writer states..........BUT, here in Florida, it was quite welcome!

Really helps to keep the engine bay temps down, as well as the firewall. :read2:
 
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