Do Carter's really only need 3psi max????

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xLURKxDOGx

xLURKxDOGx

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I was curious because i was watching videos on carbs on youtube and kept running across a guy the makes a point of saying "caters need 3psi max" like he's getting paid to say it. Myth? I have a 500cfm and its pulling 6psi after the filter and 8 around 65. Could to much PSI within reason cause flooding/bad mileage??


Thanks!!!

Jake
 
No more than 5 has always been my rule of thumb.
 
RustyRatRod said:
No more than 5 has always been my rule of thumb.
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Ok thanks rusty!!! I figured that guy might have been onto something, seeing that he's been at it for 30 years. I ordered a pressure regulator and now tryng to figure out how to plumb it correctly. I have a stock mechanical pump. AN fittings seem to be what "in". Is 4an closer 3/8 or 5/16 as far as lines go??? Want to make sure i get it right.



Jake
 
Carters are more sensitive to fuel pressure for sure.
 
What were the factory fuel pumps rated at for fuel pressure on cars that came out with AFBs?

Hysteric
 
-6 an would be around 3/8"
 
For 3/8th you would need 6AN. Take the number and put it over 16. Reduce the fraction and you come up with the size.

Example: 6AN: 6/16 reduces to 3/8. Another example 8AN: 8/16 reduces to 1/2.

Google "Army Navy fittings" for more info.

Also, I was messing around on Epay the other day and searched "Nascar" in parts and accessories. Saw a lot of prebuilt AN type lines with insulation and all kinds of stuff. Too bad the fuel line from the regulator to the carb is way, way down on my list right now.
 
AN -4 (1/4") is way too small for a gas line. You'll have to use -6 which might seem large for a stock motor, but it works just fine. -6 is the most widely used size and has the largest variety of fittings, adapters, and hoses & hose ends.
 
oldkimmer said:
.................5.5-6.5...............kim........
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sireland67 said:
-6 an would be around 3/8"
Click to expand...

Dragonbat13 said:
For 3/8th you would need 6AN. Take the number and put it over 16. Reduce the fraction and you come up with the size.

Example: 6AN: 6/16 reduces to 3/8. Another example 8AN: 8/16 reduces to 1/2.

Google "Army Navy fittings" for more info.

Also, I was messing around on Epay the other day and searched "Nascar" in parts and accessories. Saw a lot of prebuilt AN type lines with insulation and all kinds of stuff. Too bad the fuel line from the regulator to the carb is way, way down on my list right now.
Click to expand...

69_340_GTS said:
AN -4 (1/4") is way too small for a gas line. You'll have to use -6 which might seem large for a stock motor, but it works just fine. -6 is the most widely used size and has the largest variety of fittings, adapters, and hoses & hose ends.
Click to expand...

Thanks for all the info, 6an it is.

Jake
 
The answers are "right in the book." Go over to MyMopar and download a few shop manuals over the years. 67 is a "good year" as that included B /RB with AFB and hemis. 69-70 would add in 340 with a Carter, "before" ThermoQueen came along.

I think the "fussy on pressure" deal came mostly with "modern" chineseoated needles and seats which don't seem to tolerate pressure like they ust'ha.

Below are 67, 69, 70, and 72 pump pressure specs Notice that some of them are over 7 1/2 psi.

In the 70's I never CONSIDERED running a regulator, or even bothering to check pressure unless I perceived a problem. I used to run a big solid state pump I can't remember the name of, and one of the Carter motor drive pumps when it first came out.
 

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67Dart273 said:
The answers are "right in the book." Go over to MyMopar and download a few shop manuals over the years. 67 is a "good year" as that included B /RB with AFB and hemis. 69-70 would add in 340 with a Carter, "before" ThermoQueen came along.

I think the "fussy on pressure" deal came mostly with "modern" chineseoated needles and seats which don't seem to tolerate pressure like they ust'ha.

Below are 67, 69, 70, and 72 pump pressure specs Notice that some of them are over 7 1/2 psi.

In the 70's I never CONSIDERED running a regulator, or even bothering to check pressure unless I perceived a problem. I used to run a big solid state pump I can't remember the name of, and one of the Carter motor drive pumps when it first came out.
Click to expand...

Thanks for the info!!!

Jake
 
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