Air pan testing?

Does anyone have real world, back to back, testing results of adding an air pan to seal the carb to the hood? I'm in the process of building one for my Road Runner, and wondering if it will actually pick the car up some?

Jeff...There was a thread quite some time ago about air pans. I do believe there was results posted. Did you try a search in the race forum?

I did. Couldn't find any results. Might have been more than 2 years ago.

Vs nothing?
Can't imagine there is ever a downside with a air pan with a scoop as pictured.
However, depending on height available under the scoop, seems any velocity stack, even very short would-be a plus with an air pan.
I would think the biggest unknown would be what effects any wind shear across the carb might be at play regarding scoop inlet air velocity vs internal scoop volume past/downwind of the carb inlet.

edit, but with a pan that big nearly extending out over the headers, I'd be inclined to take some preventive measures to prevent generating another large heat source from radiating? more heat into inlet air.

Yeah...It probably was longer than two years...

I consistently picked up a tenth and 1-1/2 mph on my A12 running in Stock Eliminator and SS when running the factory baseplate.

I used to have a six pack hood on my cuda years ago. Sealing it to the carb was worth a tenth and 1.5 mph, but that was on a mid to low 11 sec combo. There's a lot more air flow across it at low 9 sec speed! Won't know until you try it, but I'd bet it helps.
Then this tidbit...the 5" cowl hood that's currently on the car matched the other hood's best ET and MPH...and the cowl wasn't sealed to the carb.

We went from this unsealed scoop


To this


No change, we didn't pick up a thing. A/Fr's were the same too

Couple of years ago I did an A B A test. At the time I hadn't run a jetting loop so it was somewhat lean. With the pan was worth .05@2 mph.
Doug

Tig...the lexan scoop looks better even if it isn't worth any power.

Much slower car than OP's, but open T/A Challenger scoop to sealed was a solid .1+ and 1+ MPH improvement

x2

We tested my air pan setup when my current 410 c.i. small block was on the dyno a few months ago . Weather wasn’t optimum for testing and it was’ t an actual sealed to hood test . We made pulls without the setup ( open carb , no air cleaner ) and with my filter / air pan .. the results were : No loss or gain in horsepower or torque with the air pan or without . I am sure there is a gain when in the car especially in cooler air . It is good to know however that my setup isn’t hurting my performance , I like having the air cleaner especially at dusty tracks.

I don't remember the et or mph difference on my Dart with and without the air pan. It is slower with it off and the afr's are all over the place, not just at high speed but everywhere, it seems unhappy the entire run. I did A-B-A tests, and the results were the same each time. I run a belt drive fan so that may have something to do with the afr's at lower speeds.

During my “oh S where’s my hoodpins” experiment there was no negligible et difference running without my hood. I do run the UNI air filter to keep out rocks.

Worth mentioning - if you search the subjects you want in google, a bunch of old Moparts and yellowbullet threads will show up, it works surprisingly well, I've found some valuable info from a decade ago that way.

I haven't sealed my scoop yet but I was surprised to see that removing my air filter completely lost 0.1 in ET and 1 mph back to back at GLD. Am definitely going to be making some type of air pan in the future.

I did do the google search, and came up with a thread from 2011. It was a 50/50 yes it worked, no it didn't work thread...

I have 2 cars. A 67 Barracuda, and a 70 Duster that picked up over a tenth in the 1/8 mile when we sealed the 440 6 pack scoops up to the hood.

The Barracuda was good for 1.5 tenths in the 1/4.

The day I tested this on our Duster it went 6.76 without, 6.66 with and 6.76 without.

One of the race cars that I tune is a COPO Camaro. We've run it multiple times with and without the scoop hooked up to the throttle body and the difference is 2 tenths. Runs 9 tens with the air pan, 9 thirtys without the pan.
https://youtu.be/oHcrXo0P6aY

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 agree with the many variables aspect, and why the results many report may be no more than GIGO.

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/

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

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.

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.

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.

Interesting results from everyone. Good timing as I'm currently building a cowl plenum induction on mine.

I have tested using a complete air cleaner, then the base only and then no air cleaner with a hood with no scoop on my old 1963 Plymouth 415 HP M.W. stocker, it ran .03 faster with the base only
Try testing yours and let us know what it does
I'll bet it is worth 2 to 3 + MPH increase in the 1.4 mile

Also don't forget, the cooler fresh air will most likely require more jet.

Couple guys here who have 1968 Hemi a-body type scoops on their race cars have made some air relief cuts or holes drilled in the back side. Maybe too much air coming in at speed messes up the carburetor signal?

My brother put an air pan on one of his cars years ago as it was burbling and not running totally smooth at the top end. It went slightly faster afterwards, but that may have been due to it being able to run clean all the way thru the quarter vs the pan being a speed adder all by itself.

A friend had a '65 Satellite with a sealed Hemi style scoop, no air filter and a flat air pan over a 360. Car ran well but occasionally slowed up on a run, then went back to what was expected. He cut a few "vents" in the sealing foam and the car stopped the random slower runs. We figured it had something to do with turbulence. I'm sure a good filter assembly or at least a good baseplate helps minimize any possible turbulence.

There's likely some good testing that was done back in the day as to the best execution on your car and scoop in the old DC chassis book. I know there's general hoodscoop practices chronicled which include scoop placement and inner scoop ideals. It's worth something for sure when it's done right. Outside air versus a mixture of radiator and header air is one. Not having air running over the carb and affecting the booster signals is another.

I riveted the pan to a drop filter base. That enables an inlet radius, the ability to use the original filter assembly and lowers the entire assembly.

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