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Re: Sealed Hood to Air Pan [Re: MR_P_BODY] #917185
02/01/11 11:53 AM
02/01/11 11:53 AM
Joined: Jul 2004
Posts: 1,145
Arizona, USA
gsmopar Offline
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Can you guys post some links to the material used, specifically the foam, and any "best known methods" for cutting the holes, etc... I'd like to seal mine this weekend.

It's warm here in AZ, and I have no problem doing some back to back testing.


Re: Sealed Hood to Air Pan [Re: gsmopar] #917186
02/01/11 12:41 PM
02/01/11 12:41 PM
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Belpre,Ohio
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CHAPPER Offline
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For cutting the foam,,use an electric carving knife. For cutting the hole in the aluminum, metal, etc , I have access to a water jet machine that does an awesome job.
The foam is usually avaiable from upholstery shops' 'scrap' pile for little to no cost.

Last edited by CHAPPER; 02/01/11 12:43 PM.

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Re: Sealed Hood to Air Pan [Re: gsmopar] #917187
02/01/11 12:45 PM
02/01/11 12:45 PM
Joined: Oct 2003
Posts: 7,506
Az
Crizila Offline
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Az
Quote:

Can you guys post some links to the material used, specifically the foam, and any "best known methods" for cutting the holes, etc... I'd like to seal mine this weekend.

It's warm here in AZ, and I have no problem doing some back to back testing.




I'm sure some of the scoop Mfgs like Harwood will sell the sealing foam, but I got mine from Home Depot ( probably not fire resistant though ). Cut my hole with a saber saw. Cut another circle 2" in diameter larger than the hole in the hood. Glassed it to a 3" tall air horn. Secured it to my carb with a cross bar bolted to my air cleaner stud. I can run with or with out my K&N air filter this way. Unless conditions are real dirty, I race without the filter. IMO, no matter how big your filter is, they are a restriction. If your car runs better with a filter, you got another problem. Beautiful car BTW!


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Re: Sealed Hood to Air Pan [Re: Crizila] #917188
02/01/11 01:16 PM
02/01/11 01:16 PM
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Posts: 2,422
Pittsburgh PA
Eric Offline
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5.53 @ 125 1/8th on the launch control..more left in her!

Re: Sealed Hood to Air Pan [Re: Eric] #917189
02/01/11 01:33 PM
02/01/11 01:33 PM
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Sweet Home Alabama
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MRMOPAR622 Offline
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gsmopar,when you seal the scoop to the hood even if it picks up,you still may can get a little more out of it jetting up a couple of sizes.

PS I have also saw some big scoops on cars,but they only cut a small round hole in the hood.

Last edited by MRMOPAR570; 02/01/11 01:36 PM.

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Re: Sealed Hood to Air Pan [Re: gearhead01] #917190
02/01/11 01:55 PM
02/01/11 01:55 PM
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Florida
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Re: Sealed Hood to Air Pan [Re: StewartP] #917191
02/01/11 01:55 PM
02/01/11 01:55 PM
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Florida
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Re: Sealed Hood to Air Pan [Re: StewartP] #917192
02/01/11 01:56 PM
02/01/11 01:56 PM
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Florida
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Re: Sealed Hood to Air Pan [Re: StewartP] #917193
02/01/11 01:56 PM
02/01/11 01:56 PM
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Florida
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Re: Sealed Hood to Air Pan [Re: StewartP] #917194
02/01/11 01:57 PM
02/01/11 01:57 PM
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Florida
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Re: Sealed Hood to Air Pan [Re: MRMOPAR622] #917195
02/01/11 02:19 PM
02/01/11 02:19 PM
Joined: Dec 2007
Posts: 10,542
BROOK PARK, OH
WILD BILL Offline
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Quote:


PS I have also saw some big scoops on cars,but they only cut a small round hole in the hood.






Could that be a problem? The hole in my hood is right over the carb and roughly the same size or slightly bigger. Carb is roughly an inch and a half to 2 inches below the hood sealed W/ a moroso hood pan kit.

Re: Sealed Hood to Air Pan [Re: BobR] #917196
02/01/11 02:31 PM
02/01/11 02:31 PM
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Thigh-Gap Junction
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Quote:

If it isn't in the boundry layer there is no positive pressure at the carb.




I believe you meant to say ABOVE the boundary layer.

I've always had a mini-airo scoop with a K&N flat panel filter mounted in it's base and it has always been a predictable car. One reason for the filter is to keep junk out of the engine but I also did it to stabilize the air above the carburetor. IMO, if you just have a hole with a scoop above it you're gambling in the unpredictable and often counter intuitive world of compressible fluid mechanics. My filter might cost a little top end speed but I'm a bracket racer not an ET chaser.

The shape of the air stream above the hood likely has many influencing factors such as the length of the hood, angle of attack, and the shape of the nose of the car before the hood. Trying to find a solution that works in all cases is most likely a lost cause.
My new plan is to go back to a stock hood (in glass) and take air from the nose of the car on both sides of the radiator. I'll also install air deflectors behind the grill to try and generate some additional pressure. As it is, I have around 2" from the top of the carburetor to the underside of the hood. Since the venturis are 1-13/16" (with annular boosters plugging them up) I figure the air should be fairly lazy making the bend and it will have the full 360 degrees available.
I wouldn't put a cowl hood on anything. Those things look totally 'High School' to me.

Re: Sealed Hood to Air Pan [Re: @#$%&*!] #917197
02/01/11 02:42 PM
02/01/11 02:42 PM
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I made these out of some radio speaker grills. On the return road the rear slicks are bad to sling stuff up in the air on a dragster.

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Re: Sealed Hood to Air Pan [Re: MR_P_BODY] #917198
02/01/11 02:48 PM
02/01/11 02:48 PM
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Left Coast
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"Your scoop opening needs to be OUT of the boundery layer, not in it."

Absolutely right, Mike. Thanks for correcting my brain fart.

Re: Sealed Hood to Air Pan [Re: gsmopar] #917199
02/01/11 02:55 PM
02/01/11 02:55 PM
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Belpre,Ohio
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Quote:

Can you guys post some links to the material used, specifically the foam, and any "best known methods" for cutting the holes, etc... I'd like to seal mine this weekend.

It's warm here in AZ, and I have no problem doing some back to back testing.







Bring home LOTS of info and report back soon!!


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Re: Sealed Hood to Air Pan [Re: @#$%&*!] #917200
02/01/11 02:58 PM
02/01/11 02:58 PM
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Left Coast
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"I believe you meant to say ABOVE the boundary layer."

Yes. It's been a while since I have discussed this. Mike already schooled me. The message that it takes a specifically designed aftermarket hood to achieve any kind of positive pressure at the carb is valid, though. Even the best designs aren't really hugely effective as any HP gain has to be above what the addition scoop drag negates. A bad design can even venturi pressure out of the scoop. That's probably why the SS/H cars aren't sealed.

Re: Sealed Hood to Air Pan [Re: BobR] #917201
02/01/11 03:44 PM
02/01/11 03:44 PM
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Az
Crizila Offline
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Issues not even discussed here are engine compartment pressures and temps. Big motors generate big heat, which means big radiators and big fans, which means much higher than normal engine compartment pressures and temps for stock bodied cars. Another reason to run a sealed scoop. One of the tricks that was used with the early max wedge cars was to raise the rear of the hood - and most were running sealed scoops - even if they were in the boundry layer - cold air was first and formost.

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Re: Sealed Hood to Air Pan [Re: gearhead01] #917202
02/01/11 07:38 PM
02/01/11 07:38 PM
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Florida
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Re: Sealed Hood to Air Pan [Re: StewartP] #917203
02/01/11 07:38 PM
02/01/11 07:38 PM
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Re: Sealed Hood to Air Pan [Re: StewartP] #917204
02/01/11 07:39 PM
02/01/11 07:39 PM
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Florida
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