Re: Air pan testing?
[Re: AndyF]
#3175151
09/14/23 12:11 PM
09/14/23 12:11 PM
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Joined: Jan 2003
Posts: 19,378 Las Vegas
Al_Alguire
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 19,378
Las Vegas
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A LOT of variables, cannot simply build an air pan and expect great results. You will need more jetting for sure. If the scoop is sized properly for the application you will certainly see a gain. Those lexan boxes are NOT sized properly for much more than a grocery store 318.
"I am not ashamed to confess I am ignorant of what I do not know."
"It's never wrong to do the right thing"
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Re: Air pan testing?
[Re: Al_Alguire]
#3175154
09/14/23 12:41 PM
09/14/23 12:41 PM
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Joined: Dec 2003
Posts: 22,697 Bitopia
jcc
If you can't dazzle em with diamonds..
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If you can't dazzle em with diamonds..
Joined: Dec 2003
Posts: 22,697
Bitopia
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I agree with the many variables aspect, and why the results many report may be no more than GIGO.
Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.
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Re: Air pan testing?
[Re: Al_Alguire]
#3175155
09/14/23 12:46 PM
09/14/23 12:46 PM
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Joined: Jan 2003
Posts: 2,931 A shed in England
Tig
master
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master
Joined: Jan 2003
Posts: 2,931
A shed in England
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I found this interesting, seems you don't have to build the scoop as big as you think you might. https://www.dragzine.com/tech-stori...p-speed-with-a-forward-facing-air-inlet/
'74 Challenger..9.46 @ 145.9 1/4, 6.001 @ 118 1/8 so far. 4023lb !!! # N/A, Marsh performance 655ci, Indy Maxx, T/R, Indy 600-13 X's, Street legal, pump gas, full interior, Cal-Tracs, mufflers, 3:73's and real 10.5 radials. 9.51 @ 142.4 1/4, 6.003 @ 114 1/8 with our old mule KB, 572-13, 580 wedge. RHD '68 Barracuda Fastback 323ci street/strip. Best ET 13.88 @ 99.03
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Re: Air pan testing?
[Re: Tig]
#3175157
09/14/23 12:59 PM
09/14/23 12:59 PM
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Joined: Aug 2003
Posts: 4,689 On the parachute mount
n20mstr
master
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master
Joined: Aug 2003
Posts: 4,689
On the parachute mount
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The air pan/ seal the hood works, BUT your scoop is too low to the hood ( air boundry layer) and too big of an opening, sealing it will catch a LOT of air at speed. It sill take some trial and error, the solution for you may be seal the scoop and then block off the bottom part of the scoop opening. The "good air" is supposedly 2" above the hood surface. blocking some of the opening makes it smaller so helps with catching too much air at speed. Its some trial and error for sure. In my experience though, cold air is always better and it will pick up something, how much ? go back to the trial and error comment
Last edited by n20mstr; 09/14/23 01:01 PM.
....BAD A$$ STREET CAR.....
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Re: Air pan testing?
[Re: Tig]
#3175158
09/14/23 01:05 PM
09/14/23 01:05 PM
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Joined: Jan 2003
Posts: 19,378 Las Vegas
Al_Alguire
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 19,378
Las Vegas
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In your case as with ANY of the lexan boxes on a 2x4 deal it is NOT the right way. There is a pressure loss in the scoop as air passes the first carb. Keeping the scoop the same size front to rear ensures the rear carb will NOT see the proper amount of air/benefit. There is a reason scoops are tapered in the back, it is an attempt to equalize that pressure difference from to rear. althogh it will NEVER be the same. It is also an issue in a single 4 lexan box but the drop will not be as large since you are not pulling as much air at the front, but there is still a pressure loss to the rear. In the OP's case he will likely need to make the air pan MUCH smaller than the scoop he has. But in the end to see any benefit is going to require some trial and error. As that scoop opening is WAY to big. But I think with some trial and error he will find a gain it will just take some work to get there.
"I am not ashamed to confess I am ignorant of what I do not know."
"It's never wrong to do the right thing"
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Re: Air pan testing?
[Re: Al_Alguire]
#3175160
09/14/23 01:18 PM
09/14/23 01:18 PM
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Joined: Dec 2005
Posts: 11,639 Fulton County, PA
CMcAllister
Mr. Helpful
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Mr. Helpful
Joined: Dec 2005
Posts: 11,639
Fulton County, PA
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A LOT of variables, cannot simply build an air pan and expect great results. You will need more jetting for sure. If the scoop is sized properly for the application you will certainly see a gain. Those lexan boxes are NOT sized properly for much more than a grocery store 318. How the scoop is configured inside matters too. We fabbed a pan that went into the scoop - basically a Pro Stock style snorkel - to reduce the size of the opening and direct the air rather than just have it rolling around in there. Then used a pan on the carb to seal to that.
If the results don't match the theory, change the theory.
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Re: Air pan testing?
[Re: Al_Alguire]
#3175176
09/14/23 01:56 PM
09/14/23 01:56 PM
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Joined: Jan 2003
Posts: 2,931 A shed in England
Tig
master
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master
Joined: Jan 2003
Posts: 2,931
A shed in England
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In your case as with ANY of the lexan boxes on a 2x4 deal it is NOT the right way. There is a pressure loss in the scoop as air passes the first carb. Keeping the scoop the same size front to rear ensures the rear carb will NOT see the proper amount of air/benefit. There is a reason scoops are tapered in the back, it is an attempt to equalize that pressure difference from to rear. althogh it will NEVER be the same. It is also an issue in a single 4 lexan box but the drop will not be as large since you are not pulling as much air at the front, but there is still a pressure loss to the rear. Not wishing to start an argument but you are going to have to school me on this, I have a question or two. I'm no expert by any means. My understanding is that in the example described in the article, maximum engine airflow demand (1600cfm) was achieved at 47.7 mph given the size of the forward facing opening. At any speed above that, would there be a positive pressure at the rear of the scoop as the scoop is now capturing more air than the engine demands ? I agree that there must be a difference in pressure between the front and the rear on open dual carbs but my home made makralon scoop uses a common filter (and is tapered towards the rear) will this make a difference ? Also what would be the right or best way on a 2 x 4 deal ? TIA.
'74 Challenger..9.46 @ 145.9 1/4, 6.001 @ 118 1/8 so far. 4023lb !!! # N/A, Marsh performance 655ci, Indy Maxx, T/R, Indy 600-13 X's, Street legal, pump gas, full interior, Cal-Tracs, mufflers, 3:73's and real 10.5 radials. 9.51 @ 142.4 1/4, 6.003 @ 114 1/8 with our old mule KB, 572-13, 580 wedge. RHD '68 Barracuda Fastback 323ci street/strip. Best ET 13.88 @ 99.03
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Re: Air pan testing?
[Re: Tig]
#3175186
09/14/23 03:20 PM
09/14/23 03:20 PM
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Joined: May 2019
Posts: 713 Lake Villa Il
INTMD8
super stock
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super stock
Joined: May 2019
Posts: 713
Lake Villa Il
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Interesting results from everyone. Good timing as I'm currently building a cowl plenum induction on mine.
69 Charger. 438ci Gen2 hemi. Flex fuel. Holley HP efi. 650rwhp @7250 510rwtq @5700
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Re: Air pan testing?
[Re: Cab_Burge]
#3175216
09/14/23 05:59 PM
09/14/23 05:59 PM
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Joined: Mar 2003
Posts: 2,521 PA
moparacer
master
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master
Joined: Mar 2003
Posts: 2,521
PA
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Also don't forget, the cooler fresh air will most likely require more jet.
67 Barracuda street/bracket car 11.27-119 68 Dart 502 BB 8.70s-152 414 cid SB Dragster 7.65-174
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Re: Air pan testing?
[Re: Cab_Burge]
#3176167
09/18/23 08:58 PM
09/18/23 08:58 PM
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Joined: Oct 2004
Posts: 5,618 long island NY
Ari440
master
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master
Joined: Oct 2004
Posts: 5,618
long island NY
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At the time I was going 11.00s with a steal head 446ci motor.got a stop sign and made a air box to seal up against my six pack hood .on a November day got me a 10.85 123 mph
1.39 9.85 - 137 mph
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