Edelbrock 1406 secondary venturi cluster

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Billbo

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Hi all I have posted two pics of secondary venturi clusters.
The first photo the well tubes have open ends on them while my ones have small openings which are smaller than the secondary jet. does this compromise the flow? Or is the well filled with aerated fuel which is factored in the design of the metering. the first photo I looked up on the net is an old AFB Carter carb. Reason is I am eliminating the secondary bog and came across this finding. Does anyone know if this is O.K.? or do they need to be drilled out for more flow. These holes in the well tube in the second pic are smaller the the 95 stock jets! how can the metering be controlled by the jet? there is effectively a smaller restriction further along.
Any comments will be appreciated.
Regards
Billy D...
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If you have "secondary bog" then there is something besides the design a fault.
More likely jetting or tuning (as in timing or advance)

Also when you mention pickup tube design differences, did you notice how that secondary second butterfly set works?
That design is so that that top set opens depending on air flow volume (so smaller tubes and jets are a must for that design, as the secondary venturi's have more vacuum on them)
 
Every single AFB ever made bogs to some degree. If somebody says they have an AFB that doesn't bog at all, they are either lying or they cannot feel it and don't know what to look for.

The AFB is designed to bog. The secondary air door is positioned under the boosters. As such, there will always be a delay in the time it takes for the booster to see the air signal from the secondaries opening.

The AVS on the other hand was created to solve this very problem. The air door was mover on top of the boosters. In this way, the boosters see a signal as soon as the secondary throttle plates are open.

You will be able to tune the secondary bog out of an AFB only so much.
 
RustyRatRod said:
Every single AFB ever made bogs to some degree. If somebody says they have an AFB that doesn't bog at all, they are either lying or they cannot feel it and don't know what to look for.

The AFB is designed to bog. The secondary air door is positioned under the boosters. As such, there will always be a delay in the time it takes for the booster to see the air signal from the secondaries opening.

The AVS on the other hand was created to solve this very problem. The air door was mover on top of the boosters. In this way, the boosters see a signal as soon as the secondary throttle plates are open.

You will be able to tune the secondary bog out of an AFB only so much.
Click to expand...

Huh, didn't know that. :)
 
The only exception to the rule is if the carb is too small. Or
If your RPM's are high enough on the primary side only and ready to accept the secondary door openings.

Take another look at the carb's pump shot and timing.
Leave the booster alone for now. There not a part you can purchase seperatly. If you screw it up, your now looking for a trashed carb for parts.
 
In regards to the secondary bog, I am not concerned much about that. I am curious of the fact the well tubes have tiny orifices compared to the older Carter well tubes. My question is does this restrict the jetting on the secondary circuit.

Regards
Billy D...
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seams to me that Rusty has a better grip on the AFB than most of us. IMHO you can trim the air valve weights to come in sooner. and i think there will be a fine line between to much and to little. here is a hint the AFB / AVS at the rear of the main casting is a vent from the float bowel to the other by pluging this vent with JB-weld will stop flooding on hard turns. there will still be enough venting from the other vents. got this hint from an old Corvett road racer.
 
Billbo said:
In regards to the secondary bog, I am not concerned much about that. I am curious of the fact the well tubes have tiny orifices compared to the older Carter well tubes. My question is does this restrict the jetting on the secondary circuit.

Regards
Billy D...
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Click to expand...

I think it is simply a different design. I usually have an AFB style carburetor, but I apologize. Right now I do not. I am pretty sure on the one with the large orifice opening, you will find that it has a restrictor inside somewhere between the large opening and where it enters the booster.
 
"It has more vacuum on that circuit due to the air flow actuated top set of butterflies. (that upper set opens by airflow overpowering the weights that hold them closed) (They are not mechanical)
Because of this, that opening is capable of a much higher flow than we would think by just looking at it.

If you were to open that tube up your 095 jet could very well act like a 120 due to less resistance.

If you really think there is a fuel supply issue there and you are determined to re design their carb for them, pull out those counterweighted butterflies and rejet bigger for the missing vacuum. (Then you may need to open those tube inlets up)
This way you will have more flow of fuel and air both through the secondaries.

You started this thread by saying you were trying to eliminate a bog situation, and then changed to say you were not concerned about the bog but were curious about the openings.

Seems both questions have been answered multiple times.


Ok, redo, mulligan or whatever you want to call it.
After reading your other posts on the two carbs 1405 and 6, it is now clear that you know more about it than your initial post got across.
I was under the impression that you were fairly new at this stuff from the question asked about the venturi tubes being different.
My oppologies, as this is clearly not the case.

Nice work.

Carry on. :D
 
Thanks guys for the info. Rusty I think I do recall the restrictions further in the tubes as I have had Carter models many years ago. Don,t get me wrong there is no way I am tampering with the tubes!
They are staying factory.

Kind regards
Billy D...
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