Cowl hood, carb pan or scoop

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Cowl hood, carb pan or scoop

Post  BigRigTech on July 12th 2013, 11:54 pm

Right now I have a lift off 6" cowl hood on my Mustang, it was on the car when I got it. Is it worth the effort to try and make a carb pan to let the engine only draw air from the cowl area???? I'm being constantly nudged toward a hood scoop but to my surprise I don't see anyone offering a lift off fox body hood with a molded scoop on it so I would have to mould one into this hood. The Previous owner now has the same style hood on his new tubbed Mustang with the same drivetrain running 9.70's with a 418W/glide and no carb pan. He used to run 10.00 with that gear in my car with traction issues. I ran 7 passes last weekend with no air cleaner - it's not going to be that way at the race in August - the air cleaner is on to stay. The first two were Friday night, back to back passes at 10.91 (83/95 jets) after running an 11.08 (83/93 jets) with the air cleaner on. I can get a breathable top, my buddy saw 2HP on his SBC on the dyno when they tried one - so they basically got all the HP back that they lost with the air cleaner. I saw about a 5HP lose with a drop base air cleaner on the dyno. The dyno owner suggested a flat base and 4" filter would get that back so that is what I bought. I'm hoping some of you Mustang guys will have done the experimentation for me....Very Happy I've read that if you seal it up too well you can cause issues with the carb leaning out the mixture at WOT??? Old pic from last year.





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Re: Cowl hood, carb pan or scoop

Post  BigRigTech on July 13th 2013, 8:51 am

I like the blue one as that is similar to my situation. I could buy a new flat glass hood and put a scoop on it. I have a guy offering me my a low cost paint job in return for advertising his body shop on my car. I have to bring him over here to have a look in the near future.



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Re: Cowl hood, carb pan or scoop

Post  LivermoreDave on July 13th 2013, 9:09 am

Some cars look good with cowl induction hoods, some don't! My answer to your question is seal it. If the cowl's manners create a different tune up, tune to it! An article Warren Johnson wrote several years ago (rare) stated his NHRA P/S Pontiac's scoop provided 1 lb. of boost (pressure) at 200 mph! IMO, sealing an air scoop has it's benefits although one must look for them!

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Re: Cowl hood, carb pan or scoop

Post  BigRigTech on July 13th 2013, 9:36 am

I see an awful lot of fox body's with cowl hoods so some of them must be sealed up. NASCAR has been doing but for years so it must work OK....LOL
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Re: Cowl hood, carb pan or scoop

Post  70FB on July 13th 2013, 10:02 am

I was told to take a piece of yarn and scotch tape and tape it to the top of the cowl at the windshield. Then as you go down the track,look at it and see which way its blowing.If the yarn is blowing toward the windshield then an airpan will do very little. If it's blowing in towards the carb then you are getting the high pressure area at the base of the windshield and an airpan would help a lot. I did this on mine but I can't see any difference. It's got to help though. I really haven't tested enough with or without it. JMO.
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Re: Cowl hood, carb pan or scoop

Post  LivermoreDave on July 13th 2013, 10:18 am

70FB posts a good evaluation as to the aerodynamics of a cowl induction hood, although a minimal amount of air will flow freely into the cowl's opening simply because this is a low pressure area of the automobiles design. Sealing the carburetor to the hood will offer the carburetor's air inlet cooler air, unlike the air from the engine compartment with an unsealed carburetor. The induction of cooler air may offer a performance gain when the carburetor is tuned to accommodate the influx of cooler and fresh air supply.

During a test of my 1970 Mustang with the factory non-ram air hood scoop (Mustang) and the carburetor sealed to the hood a sensor was attached to the carburetor's air pan facing toward the supply of fresh air. The temperature of the air supply dropped nearly 30 degrees from the starting line to the finish line.

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Re: Cowl hood, carb pan or scoop

Post  maverick on July 13th 2013, 2:19 pm

As long as excess turbulence isn't screwing with airflow in the venturis, put a pan on it. You won't get a "ram effect" without one, and cooler air is the ticket if any free h.p. is to be gained. Cooler is better.
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Re: Cowl hood, carb pan or scoop

Post  bbf-falcon on July 13th 2013, 2:41 pm

I had a 6" cowl on my ole Maverick. After I built a Tbolt style airbox and dryer tubes to the grill it dropped my et by a full 1/10th thru the 1/4mi.

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Re: Cowl hood, carb pan or scoop

Post  maverick on July 13th 2013, 4:10 pm

bbf-falcon wrote:I had a 6" cowl on my ole Maverick. After I built a Tbolt style airbox and dryer tubes to the grill it dropped my et by a full 1/10th thru the 1/4mi.

Pretty wild how different cars want different deals, Rick. I put one of those on the ol' Ranger and it laid down like a bloodhound on a hot day. Lost .2 with no other changes.Shocked  Naturally, I tossed it.
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Re: Cowl hood, carb pan or scoop

Post  BigRigTech on July 13th 2013, 4:21 pm

I'd like to try it now so I can decide on changes before I get the car painted this winter. The next race shouldn't be do hot and as a result the air should be better. Any gains could be skewed by this. I'm going to build my own pan next week. I'll post some pics.
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Re: Cowl hood, carb pan or scoop

Post  maverick on July 13th 2013, 4:42 pm

maverick wrote:
bbf-falcon wrote:I had a 6" cowl on my ole Maverick. After I built a Tbolt style airbox and dryer tubes to the grill it dropped my et by a full 1/10th thru the 1/4mi.

Pretty wild how different cars want different deals, Rick.   I put one of those on the ol' Ranger and it laid down like a bloodhound on a hot day.  Lost .2 with no other changes.Shocked   Naturally, I tossed it.

FWIW, that car had a short cowl hood, no air filter.
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Re: Cowl hood, carb pan or scoop

Post  BigRigTech on August 11th 2013, 4:49 pm

I finally got time to make my carb air pan, I will have a chance to try it next weekend at the Bracket Bash. It would be a good weekend find my groove and go some rounds, best payouts of the year....Wink.....No box and no brake....I'm screwed...LOL





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Re: Cowl hood, carb pan or scoop

Post  bbf-falcon on August 11th 2013, 5:09 pm

W0W, Nice job:) 

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Re: Cowl hood, carb pan or scoop

Post  BigRigTech on August 11th 2013, 5:21 pm

$27 in 18ga tin and $2 in from from Home Depot...LOL....Air saw, mig, grinder and el-cheapo Princess auto bench top metal bender....Test fit a few times before the final sanding of the welds and some paint. My buddy said he would duplicate for me this winter in 16ga aluminum if I want as he works in a sheet metal shop. I ran the car for about 30 seconds today after I changed the oil and it's unreal how much heat comes off those 2" headers in that little time. I can't see how this pan is not going to help in some way.Very Happy 
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Re: Cowl hood, carb pan or scoop

Post  1faststang on August 12th 2013, 8:40 am

Looks Awesome!!.. Much better than the one I'm using.. Wanna build me one??..lol
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Re: Cowl hood, carb pan or scoop

Post  BigRigTech on August 12th 2013, 9:07 am

That can happen if you bring your car over when she's put back together. We can duplicate this to fit your hood. I still have the patterns in the garage if you want to modify them to fit your car.
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