Ram air, air flow?

[quickd100]

I'm in the process of fabricating an air box/aircleaner for my Weiand hemi tunnel ram. In the past I've been feeding a 440 with 25.1328 square inches of scoop area. I'm tight for carb to hood clearance, the box feeding the carbs will be only 3" high. I'd like to keep it 8" wide but that would be only 24 square inches. Would this restrict the air volume to the carbs and hurt the horsepower? I can go wider but would like to keep things as compact and neat as possible. As far as a filter goes I'm thinking of a flat rectangular style mounted in a plenum in front of the intake manifold. Dave

[DavidHarsay]

A picture may help....

Scoop area is way too big on most ram air systems, and actually hurts performance.... not saying that 24sq inches is too big, just wanted to get your attention.

Look at some of the scoops on indy cars, formula 1 cars... here's an image to illustrate what a low profile small inlet area scoop may look like...


The idea is that it's a divergant duct, which efficienlty creates relative high pressure from the high velocify atmospheric pressure. If you concentrate the efforts on a nice rounded inlet, minimize angles, you should see some improvement even with a much reduced air inlet area. You mentioned flat rectangular style, and were concerned about the performance aspects... well, anyway. There's a lot more to it, just food for thought.

[quickd100]

Maybe I should back up a bit. My scoops are 2, 4" diameter round ducts in the inner headlite sockets with two 4" air tubes that terminate in a sealed air box. The headlite sockets are located in a a high pressure area, it definately does work as I picked up 3 mph over an unsealed unit on back to back tests.
The same system will be feeding 2, 750's on a tunnel ram. I have to fabricate a new air box above the carbs with an extension in front of the manifold to hold the air filter. Should the opening to the airbox above the carbs be AS LARGE as the combined size of the 2 scoops, or will a smaller opening work as well?
You can see the location of the scooped in the picture. Dave

[Mark Workman]

As Arizonaspeed said, you are converting velocity energy into pressure, so any reduction in area anywhere in the tract will work against that. The air also needs to turn the corner into the carb, and slower moving air turns better. But I doubt that you'd see a measurable difference between 25 and 24 square inches.

[F1Fever]

and what's a 1/3" of an inch? 8.0 vs 8.3 isn't too bad if you can go wider