fuel pressure range for 750cfm carb set up for e-85?

[fast14]

What is common fuel pressure range to look for on 750cfm carb converted for e-85?
Thanks!

[crate late]

5.5-6.5psi 6psi ideally

[Matt49]

Based on your question it is probably worth clarifying that a carburetor does not effect fuel pressure, only the pump does.
That being said, cratelate is right on the money for what you want to feed a Holley with. Much more pressure than that and you're going to have trouble with seating the needle valves. Do NOT trust what the pump says its output is. Get yourself a $12 gauge and hook it up to the fuel log and find out for yourself. A regulator is also not a bad idea.

[50j]

The carb does affect fuel pressure in a way. If it's using more fuel volume, and it will with E-85 or especially methanol, some pumps won't put out enough volume to keep up and fuel pressure can fall off at wide open. Part of that is fuel line size too. I run E-85, and wouldn't want to try 5.5 psi. I use more, have never had any problems with needles and seats and have never ran the bowls dry like you will with inadequate delivery. What carb do you have fast14?

[brad hibbard]

E-85 likes 7 to 7 1/2 pounds --- here's the catch--- are you running a belt drive pump with a return type regulator or are you running a block mount pump with a dead head regulator?

E-85 set-ups should run an elevated pressure pump and high flow regulator

We have not been satisfied with block mounted pumps and return type regulators
I know plenty of folks use them but it's not our recommendation.

If you are spilling fuel at idle with 7 1/2 pounds you have the wrong needle valves

E-85 we try to run the same idle pressure as WOT even with a return system.

Brad

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