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Originally posted by SonnyJames:
^^^^^ that said why would anyone bracket racing run any air scoop??...other than needing space

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Originally posted by stk 758 BP!:
Tony, I tried the KN sealed to the hood, open at cowl. Car was never consitent. At a divisional race I duct tapped it up. Car picked up so I put a flat top on the air cleaner and it’s still that way. Removed duct tape and closed factory flaps and sealed it.

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Originally posted by Footloose:
There are a lot of good credible experiments here. My cowl hood is steel. I liked the way it looked when I was younger, not so much any more. I still have the factory hood. I wondered while going down the track,what about all the air coming through the grill. Will it catch all the air to the firewall. Maybe slow it down. I had to have a tall hood because I ran a blower for years.

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Originally posted by wideopen231:
On subject of forward facing scoop and rear facing cowl. Probably zero difference. Based on fact I watched a guy turn enderle hat around backwards to prove air down track made no difference. He ran exactly the same with hat facing backwards as he had with it correctly facing forward.

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Originally posted by FootbrakeJim:
With the cowl not sealed, I don't know if it will, help, hurt, or run the same. When I added a cowl scoop to my hood, I first cut a 16x18" opening in the hood beneath the cowl. Ran it that way, and saw virtually zero difference in ET or MPH vs. previous runs in nearly identical conditions. Figured it was still breathing hot underhood air. I guess it is mostly about pressure differential - depending on the car, mine may have been blowing hot air out of that cowl, rather than bringing in cooler outside air. I later bought a 2'x3' sheet of .100" thick aluminum, cut a 12 inch hole in it, and pop-riveted it to the base of my air cleaner, then glued on a 4" tall wall of 2" thick, gray, closed-cell foam around the perimeter, to seal it to the hood. That ensures it breathes only outside air, and made an immediate difference in both ET and predictability, (not necessarily consistency), because it was no longer breathing super-heated air off the headers, and/or through the radiator. But no way you can nail down to a specific ET gain, because that varies, with the difference in air temperatures between engine compartment vs. ambient (outside) air. The cooler the outside weather, the bigger difference in ET.

Here is a trick I read about in one of the old Alex Walordy E.T. drag racing books from about 30 years ago: Tape several 2-3 inch long strands of yarn or string along the edges of your cowl or scoop, and take video of them as you are going down track, they should be blowing into the scoop. If not, you have a pressure differential problem.
And here is my explanation on the "consistency" vs "predictability" of it: The car was definitely quicker afterward, (I'd have to dig up old logs from 15 years ago, but IIRC it was a difference of around .01-.03), but it may have been a bit more consistent without the air pan, because I always ran the car with a specific amount of heat in the engine, and so it was always breathing heated air, no matter the outside temp. BUT, when I began using a weather station, the prediction feature was almost worthless, until I sealed the air inlet to the cowl. Suddenly the ET predictions were a LOT closer, and I realized then, that the engine was now taking in the same "quality" of air that the weather station was sampling. That unit was calculating it's ET prediction on the ambient air temp, not the 200*-600* stuff my engine had been breathing before...