Six pack to The summit

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K.O. SWINGER

Meeting in the alley since 1976
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I would like to start this thread for the six pack enthusiasts and gurus on this form. Six pack seem to be a bit of a hoodoo voodoo science. I have no interest in negative opinions of the setup only in helping those running them or that are interested in them understand and improve their systems. I will be the first to say I am just learning, but I love the setup and would love to hear any helpful facts or theories. I will start with this question what happens inside a six-pack manifold at wide open throttle I have heard the outboard carburetors take over does anyone know the percentage? Is that true? So let's begin
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Outboard carbs take over?
This isn’t true. The outboard carbs are of a higher flow rating than the center, true, but the center still contributes. I can see that the center carb, being in the center has less of a direct impact on what fills the cylinder over the outboard carb since it has a better placement over the runners path.

Once the carbs are open, there all moving air and fuel.

There is an excellent thread on this at FBBO.
 
There is a definite learning curve when dealing with a six pack setup. I had my trials & tribulations with them in the mid to late 70's street racing them here in Texas.
 
Thanks, this is a info share , I hope! then all carb intake air velocity at wide open throttle is the same on all carbs?
 
I guess my question is which carbs are feeding which cylinders or what role does the center carb really play at wide open throttle?
 
I never read or seen any concern over the amount of air velocity through any single carb. The amount of fuel delivered is determined through the amount of velocity above, through and below the carb, passed the fuel feeding booster. Since fuel delivered is dependent on the amount of air rushing passed and through the booster, the only way I can see an issue is if the carb itself is to large or small. Like you would on a 2 or 4bbl.

I really don’t think this is an issue.

The center carb is feeding air and fuel. At what percentage I do not know. But it is still contributing.
If you really wanted to find out, I’m sure there is some type of equipment out there that could measure it all. For us guys with no money or equipment, the best you can do is to do a lot of thinking on Venturi size and math that goes with it.

A similar thought pattern was introduced many years ago and questioned the validity of the TQ’s primary side at WOT, as some magazine put forth the theory that the primary side contributed nothing or near nothing when at wide open throttle. Which isn’t true and later proven otherwise.

IMO, your overthinking this.

If there was a way (which I’m sure you could rig up linkage to do so) to test each carb on the engine by itself or in pairs, while removing the other carbs and dyno test thereafter in order to see what’s going on, then you would have a clearer picture that I’m sure will generate more questions than answers and bring out some crack pots with there babbling theory’s.

(In which now become tied in with the JFK shootings, DB Cooper’s & Jimmy Hoffa’s where about’s as well as the super secrecy Insidious plan of aliens disguised as humans attempting to reorganize the world and mutate humans into there own form while creating a one world order to battle the evil empire on the other side of the galaxy.)
:rofl:
 
I totally agree Rob, now I will fill you in on why it is a concern I plan on running nitrous into a forged 340 six pack most likely through a plate type system and wanting to figure out fuel and air distributation at wide open throttle. I have an original ta manifold and have no desire to start drilling holes in it for a direct Port system.
 
I would like to start this thread for the six pack enthusiasts and gurus on this form. Six pack seem to be a bit of a hoodoo voodoo science. I have no interest in negative opinions of the setup only in helping those running them or that are interested in them understand and improve their systems. I will be the first to say I am just learning, but I love the setup and would love to hear any helpful facts or theories. I will start with this question what happens inside a six-pack manifold at wide open throttle I have heard the outboard carburetors take over does anyone know the percentage? Is that true? So let's beginView attachment 1715638536
all i know is the six pac is a great setup , good luck with yours wish i had bought a setip when they were priced low , complete setup for 1500
 
I have mine actually dialed in pretty well. With 64 Jets in the center and 78s on all four corners it's kind of set up for Max effort. It idles well and comes on like a freight train . I was just trying to give people an opportunity to ask questions or share info.
 
I totally agree Rob, now I will fill you in on why it is a concern I plan on running nitrous into a forged 340 six pack most likely through a plate type system and wanting to figure out fuel and air distributation at wide open throttle. I have an original ta manifold and have no desire to start drilling holes in it for a direct Port system.


That may be a bit of a problem. I would *THINK* you would want the plate under the center carb, unless you want to run a plate under each outboard carb and not under the center carb. I had to edit that because after I posted it it didn’t make sense how I wrote it.

That makes sense in my head so it’s probably wrong, and without have that manifold in front of me I can’t remember how the outboards feed the cylinders. I do think the distribution would be better just under the center carb.

Of course, you could live large and put a plate under each carb.
 
all i know is the six pac is a great setup , good luck with yours wish i had bought a setip when they were priced low , complete setup for 1500
I got my street setup for $1500. Wieand Cross Ram for a big block. I also have another set of manual (Ford) carbs on the same intake. I'd love to take my car to the strip and test them both. Someday.

And yes, I realize this isn't the best intake to use. But I have them, so I will. :lol:
 
The original NOS (the company) systems used plates with bars under each outboard and a spacer under the center. Six barrel intakes are single plenum so whatever gets below the carbs can reach all the cylinders. If you really want big power and tune-ability run foggers in each port.
 
The original NOS (the company) systems used plates with bars under each outboard and a spacer under the center. Six barrel intakes are single plenum so whatever gets below the carbs can reach all the cylinders. If you really want big power and tune-ability run foggers in each port.


Interesting.
 
That may be a bit of a problem. I would *THINK* you would want the plate under the center carb, unless you want to run a plate under each outboard carb and not under the center carb. I had to edit that because after I posted it it didn’t make sense how I wrote it.

That makes sense in my head so it’s probably wrong, and without have that manifold in front of me I can’t remember how the outboards feed the cylinders. I do think the distribution would be better just under the center carb.

Of course, you could live large and put a plate under each carb.
Yes I have seen plates on the outboards only but now nitrous Express makes their kit just for the center carb? Which leads back to my initial question about what happens under full throttle inside a six-pack manifold in relation to air fuel mixture
 
The original NOS (the company) systems used plates with bars under each outboard and a spacer under the center. Six barrel intakes are single plenum so whatever gets below the carbs can reach all the cylinders. If you really want big power and tune-ability run foggers in each port.
Please read bottom sentence of post 7
 
I'm hoping to hear from Brian six pack that mod man set up of his looks off the hook. I know the mod man is a single plane sharing one large plenum but I would love to hear about it.
 
I got my street setup for $1500. Wieand Cross Ram for a big block. I also have another set of manual (Ford) carbs on the same intake. I'd love to take my car to the strip and test them both. Someday.

And yes, I realize this isn't the best intake to use. But I have them, so I will. :lol:
That is a badass setup. Kudos
 
I have never seen or heard of a study on air & fuel flow under the carb in the multiple 6 pack carb system.
Dual quad’s in there various forms, yes.
Single plane, yes.

Some of the fuel distribution of the six pack is obvious. Not all of it since under vacuum of a running engine, the air and fuel will not behave the way you think it would or should.

Pictured below is the high plenum side of the 6 packs center carb where we can see that the air and fuel will simply travel back and forth from under the carb. The same can be seen on the low side where the plenum is deeper, then a side shot showing the mostly central location on the intake. Predicting the air and fuel flow here is easy when only the center carb is operating. How well or how much that enters each cylinder is another story since there are 90* turns at different lengths away from the center.

You could just run the 2bbl. alone by removing the outboard carbs and making a block off plate I place of the carb to stop air leaks and effectively turn the intake into a two barrel carb to study the air and fuel flow.
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Please read bottom sentence of post 7

please state your goal for the system. Six pac intakes are short runner, single plane. Any mix in the plenum gets delivered in some percentage to each port. How much depends on where the mix comes from at that moment. Distribution during tip in of the outboards is spotty but it clears quickly as they come on board. The old system was a cheater solenoid which maxed out at 250hp iirc. That was old spray at tech, and I’d wager the NX plate is much better. But still limited by volume of a single plate. Hence the comment about port injection. I ran plates for a few years.
 
Is that a mod man manifold? Sure is pretty OMG is that plate and Port injected
I’ll have to look on the PC because the picture is larger and I can lighten the colors. BUT, IIRC, it is a regular 6 pack.

Im having internet problems of late and I waited about 15 minutes between hitting the reply button to the loaded page showing the post.
 
Hey Moper! Howz things!
please state your goal for the system. Six pac intakes are short runner, single plane.
Dual plane except the Mod Man....
Any mix in the plenum gets delivered in some percentage to each port. How much depends on where the mix comes from at that moment.
Exactly what I’m trying to show....

Distribution during tip in of the outboards is spotty but it clears quickly as they come on board.
In the following pictures I address that a little bit.
 
In the first photos above, I focused just on the plenum under the carb. Once you get past the Immediate area under the carb the first runners break off very sharply and quickly and not exactly at a 90* turn, but the end runners do. The inside runners are a shorter runner with less obstruction under two barrel power.

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Yes I spent a good amount of time staring down the ports wondering what went on in there during the transition from the inner carburetor to the opening of the outboards and full throttle distributions. It would be fascinating to see it in a clear manifold with smoke or something of that nature.
 
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