Turkey Pan

[Machiavelli]

Ah yes, the much debated "Turkey Pan".
User feedback requested, fuel injected need not respond.

True or False, you tell me - the below pulled from an undisclosed web location.

Turkey pans are one of the most misunderstood engine accessories. Today with all the high tech stuff we undertake, we as a group don't often give credit to the racing people of the 60's. They did something quite unique in getting a sports car with the aerodynamics of a barn door to go 160+ mph.

Doing the Turkey Pan Mathematics

The "Turkey Pan" (cold air box) was one of the reasons that the 427 performed like it did. Doing the math helps us understand why. A hood scoop opening of 2"x10" or 20 sq. in. moving through the air for one mile at 60 miles an hour takes in nearly 8,000 cubic feet of air. Your 427 cu. in. engine, traveling the same speed, turning 2500 rpms is only using 350 cubic feet or so of air. When sealed against the hood with a rubber gasket (which most folks don't like doing because the gasket chafes the paint) forms a high pressure area between 2-5 psi of cold air pressure, depending on how fast you are moving. The excess cold air spills out through the bottom opening, thus cooling the intake manifold and the air charge running through it. It creates "free horsepower" and the only drawback to this is that you must be moving!!

I read a forum post one time where two cobra guys where talking about turkey pans and got a little chuckle when one said "I don't think the turkey pan helps at all." To make such a statement is idiotic at best. "Every" high performance intake system uses cold air under pressure to gain a horsepower and fuel mileage increase!!!

[gsharapa]

My opinion is this;

. First of all it looks great!
. Anytime you can get a cold air intake charge the better!
. Turkey Pan will keep more of it around the carb vs letting all of it just flow freely in the total engine compartment.
* The draw back has always been adjustments to the carb or when you need to change jets etc. With these new Turkey Pans that have the removable sides like the one I
have, this eliminates that concern.

[Machiavelli]

Thanks Gary, what size scoop are you using with that monster 496 AL FE?

[FIA-ERA]

"I don't think the turkey pan helps at all." To make such a statement is idiotic at best.

Well I think this statement is a little off. I can tell you with out mathematics and with a better instrument gauge, the seat of my pants, where the problem lies. It's not the turkey pan that's the problem, it's the air filter we put on top of it! The original Stellings just plain sucks! Even the KN filter as shone above still has it's limits to how much air can come in. Just do the math on the cfm flow of the air filters. They never ran filters on race motors did they. Why because they slow down the amount of air the engine needs. On the street and in most cases we have to run filters to protect the longevity of the motors. I would say most don't take the motors out every 600 miles or so to freshen them up. My car runs A LOT better with out the Stellings filters BUT I can't run around here with out a air cleaner because of all the road work and dust. I like the looks of the turkey pan, I appreciate the performance side, but after a lot of trying both ways I went away from the turkey pan. My car is happier and runs a lot better. The Turkey pan was very hard on my motor just idling around town. There wasn't enough air coming in to help it run down low. Like you said, you have to be moving to get the best use of it. I'm going to get some popcorn now. Matt

[gsharapa]

Stock scoop on my car. I'm running a Victor single plane with the carb platform cut down 1/2 inch, air cleaner base is 9 inch flat base, K&N 2.75 filter and K&N extreme top....

[Machiavelli]

Thanks Gary, any low speed vs. high speed mixture issues as described by Matt above?

[patrickt]

For predominantly street-driven cars, the real benefit of a Turkey Pan is that it seems to eliminate heat soak percolation, which can be a real PITA on these cars. My car starts fine even when really hot, in 100+ degree temps, and after sitting in the sun.

[rodneym]

I have a question:

My experience is that air is coming out of the scoop at about 40 mph. My old SPF backfired and smoke came OUT of the scoop. Doesn't this mean that air is coming out? Seems like the seal of a TP would HAVE to be pretty solid to work as designed.

But as gsharapa said, it's pretty awesome looking.

[patrickt]

Originally Posted by rodneym

I have a question:

My experience is that air is coming out of the scoop at about 40 mph. My old SPF backfired and smoke came OUT of the scoop. Doesn't this mean that air is coming out? Seems like the seal of a TP would HAVE to be pretty solid to work as designed.

Surely you remember those Chevelles with the little door that opened up in front of the windshield on the scoop that was backwards? But regardless of whether it works better or not, a backwards hood scoop looks dumb.

[vector1]

the cold air part helps, i have used an air filter that was sealed to the hood and on a moderate approx 70 deg. day the carb will be absolutely chilled form the air moving through it.

the smaller scoops used on the cobras i don't believe provide much benefit of the ram air effect, if at any speed. my thoughts are the intake must be positioned away from the boundary layer into undisturbed air, but again, i could be wrong.

[Richard Hudgins]

Originally Posted by vector1

my thoughts are the intake must be positioned away from the boundary layer into undisturbed air, but again, i could be wrong.

You are quite correct. The boundary layer on the bonnet at 100 mph is over an inch thick at the scoop opening.

Not to mention the turbulence from the radiator opening flow stalling at 80 mph and the resulting pressure waves in the stagnate flow of the boundry layer.

[BAsque1]

Originally Posted by Machiavelli

Ah yes, the much debated "Turkey Pan".
User feedback requested, fuel injected need not respond.

True or False, you tell me - the below pulled from an undisclosed web location.

Turkey pans are one of the most misunderstood engine accessories. Today with all the high tech stuff we undertake, we as a group don't often give credit to the racing people of the 60's. They did something quite unique in getting a sports car with the aerodynamics of a barn door to go 160+ mph.

Doing the Turkey Pan Mathematics

The "Turkey Pan" (cold air box) was one of the reasons that the 427 performed like it did. Doing the math helps us understand why. A hood scoop opening of 2"x10" or 20 sq. in. moving through the air for one mile at 60 miles an hour takes in nearly 8,000 cubic feet of air. Your 427 cu. in. engine, traveling the same speed, turning 2500 rpms is only using 350 cubic feet or so of air. When sealed against the hood with a rubber gasket (which most folks don't like doing because the gasket chafes the paint) forms a high pressure area between 2-5 psi of cold air pressure, depending on how fast you are moving. The excess cold air spills out through the bottom opening, thus cooling the intake manifold and the air charge running through it. It creates "free horsepower" and the only drawback to this is that you must be moving!!

I read a forum post one time where two cobra guys where talking about turkey pans and got a little chuckle when one said "I don't think the turkey pan helps at all." To make such a statement is idiotic at best. "Every" high performance intake system uses cold air under pressure to gain a horsepower and fuel mileage increase!!!

I swear by turkey pans, we are old but it works, Same thing with the cool cans with dry ice or alcohol to avoid bubbling inside the fuel lines. These technologies worked then, why not use them now?
BAsque1

[Machiavelli]

Thanks Richard, glad you took the time to run some flow tests on the JBL, you can never argue with the data.

Even more relevant to my setup which will use the SMALL scoop, the below taken from another thread -

"... we did test the small scoop configuration as well. This unit provided no flow enhancement. It actually reduced pressure at the annulus. This was due to boundary layer effects. In other words, at 100 mph, the flow is over the unit due to thickness of the boundary layer, therefore giving a net reduction in pressure."

So it seems the ONLY benefit of a turkey pan on a reasonable facsimile of a cobra is cooler air being sucked through the intake (and that's with good size scoop). The question I have is - with the small scoop, is there any cooling at all? If I understand you correctly, it would be negated completely by that reduction in pressure at the scoop mouth?

[PurpleVenom]

Originally Posted by patrickt

My car starts fine even when really hot, in 100+ degree temps, and after sitting in the sun.

Not running a turkey pan - So does mine. Seems to me for any effect, you have to be moving. JMO

Tim

[Machiavelli]

was wondering, anyone ever think about those rarely used air ducts for the brakes? a little creative plumbing and ... who knows?

[patrickt]

Originally Posted by Machiavelli

was wondering, anyone ever think about those rarely used air ducts for the brakes? a little creative plumbing and ... who knows?

A lot of us route that duct work in to the top of the foot boxes for a little fresh air down in the footsie area.

[GMS]

Here is a photo of cold air intake duct work I put on a supercharged 4.6 I started a carb top for duct work but never finished. Richard and I have often discussed the hood scoop and airflow situation.

Larry

[Machiavelli]

Hi Larry,
How's your snow blower running? Mark my words, the start of the next ice age has begun! Where do you stand on the "turkey pan" question? Hey, while you're here - seeing how the JBL Comp Chassis wheelbase is 94.3", how long would you make your sidepipes so they end neatly at the rear wheel well

[vector1]

Originally Posted by Machiavelli

Thanks Gary, any low speed vs. high speed mixture issues as described by Matt above?

running a 14" air cleaner and just changing the base from a drop to mid height changes the a/f ratio. bit more sensitive then i would have believed.

btw, i can still fit a normal scoop if desired and the jbl large scoop allows a 12" x 2 air cleaner if i remember right, i'd have to check to be sure.

[Machiavelli]

I've been looking at the K&N XStream assemblies, looks like that one will flow a lot of air. I've also been looking to see if anyone is making a micro-screen filter like in some oil filter applications http://www.kandpengineering.com/tech...ghlights.shtml I imagine a micro-screen type would give the best possible flow, seems to be the least restrictive of any filtering element out there - I wouldn't recommend in dusty environments. I do intend to use the K&P replacement for the Moroso on my motor.