How do you determine the fuel pressure setting?

[dr.occa]

If I might add a suggestion:

A return style fpr if you haven't already done so for consistent pressure and reading e.g. Aeromotive 13301

[j9fd3s]

Originally Posted by RX MIDGET

The plot thickens...
I have just installed the Mallory 4207 Fuel pressure regulator with matching Mallory gauge. This regulator has a range of 4 - 12 PSI. It was installed exactly as per instructions - super easy!

How come I can set it for 2 PSI?

I have set the Reg at 4 PSI which is half way in the Reg adjustment. (I expected it would be at the minimum setting!)
Whilst it serves the purpose set at 4 PSI, I am now wondering if the fuel pump (which I was told is 7 PSI) is actually running alot less PSI????
Car ran well before hand and the reg was filled as a precaution.
Am I missing anything?
Is the reg working?

i went thru this on my car, which has a 48ida carter pump, and holley regulator.

with the results in reverse order, i found that the 72gph/6psi pump only delivers a little more than 4psi @ the carb, its also WAY short on volume.

so i got rid of the regulator completely, because mazdas comp spec for the weber is 4.3psi, and that's about what i'm getting.

so how much PSI can you run? i think the factory spec is 3.5, which should be fine. the float level is important. with the engine running you should be able to look down the venturi's and NOT see fuel dripping from the boosters at idle. if you are, the float is too high.

i set my float for 4+ psi, so dropping the fuel pressure might lean it out, i didn't do the testing in an order where i really know that.

oh yeah and i bought a 5" diameter 0-5psi gauge (the one mr yaw used to recommend, i think)