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 Carter-Edelbrock emulsion 
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Joined: Wed Feb 13, 2013 4:04 pm
Posts: 63
My question is in regards to the differences in the Carter afb/avs emulsion tube designs with the fine holes and large opening verses and the later Edelbrock style emulsion with the larger tube holes and the smaller opening.

In the pic the 340 verses the Hemi

How do the differences play out in the fuel curve?


Hysteric


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Fri Feb 15, 2013 7:09 pm
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Joined: Fri Feb 08, 2013 2:37 pm
Posts: 1701
Somebody has done a nasty with that picture. It has been cropped and it is missing the caption. It was originally posted in the Innovate forum in March of 2007 and the caption was as follows:

"I probably shouldn’t have put these boosters on the T-shirt because the engines depicted (on the shirt) aren't related to the boosters. From left to right, they are F-M & Edelbrock 625 & 750 & 800 "AVS", Carter 3705S ('64 Max Wedge Cross Ram), 1967 335hp 440 and a '71Carter Competition Series 750 which is essentially identical to a '67 375hp 440."

The difference is the larger holes in the well tubes make for bigger bubbles in the nozzle stream and that tends to make the fuel discharge in larger globs instead of a smooth flow. A tube similar to the one with large holes under the 340 was used in some Pontiac AFBs but they only had .026” in the main air bleed tube and also had a fairly large surface in the exhaust heat exchange area in the floor of the plenum. On the other hand, some Chevrolet AFBs had tubes with no holes at all except for a kill bleed above float level. Many AFBs of all OE manufacturers had no tube in the secondary cluster. Remember, in AFBs the air comes into the well outside the tube and exits the well up the tube with the fuel.


Fri Feb 15, 2013 10:39 pm
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Joined: Wed Feb 13, 2013 4:04 pm
Posts: 63
Thanks Tuner,

Quote:
The difference is the larger holes in the well tubes make for bigger bubbles in the nozzle stream and that tends to make the fuel discharge in larger globs instead of a smooth flow.


I figured that would be the case. With the larger holes i would imagine as the larger bubbles coalesce it would manifest as an eratic afr as fuel distribution is inconsistant? Would the larger droplet size be more suitable for the majority of hotrod engines design parameters hence FM and Edelbrocks generic tube design?

Quote:
A tube similar to the one with large holes under the 340 was used in some Pontiac AFBs but they only had .026” in the main air bleed tube and also had a fairly large surface in the exhaust heat exchange area in the floor of the plenum


How does the .026" main air bleed play into this?

Quote:
Remember, in AFBs the air comes into the well outside the tube and exits the well up the tube with the fuel.


What difference does this make as opposed to how the Holley does it? Are there different factors at play in the different designs?

Thanks again

Hysteric


Sat Feb 16, 2013 7:03 pm
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Joined: Wed Apr 24, 2013 10:03 pm
Posts: 10
Which one actually resembles the one found in the Street Hemi OEM carburetors?

And, in your opinion, which one would be better for a Street Hemi?


Thu Aug 01, 2013 2:18 pm
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