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Old 04-06-2018, 10:50 AM
tortuga tortuga is offline
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Default Fuel Pump Sizing

Not being one to leave well enough alone...I installed a fuel press (smiths in a period correct aux mount under the dash -removeable with no tell tale with two screws) on my SPF.

I noticed that at big throttle settings that the fuel press was dropping WAYYY off (kinda hard when trying to keep the rear wheels in back of you and look down at the gauge).

I have a 30 GPH Carter hot dog arrangement right now, with a regulator set to 5PSI.

SO if the floats are dropping and admitting fuel to the bowls when the boosters are at full song, the pressure SHOULD go down to some extent i would think? How much?

The inter-web cites a fuel pump calc that takes HP x BSPH/constant= necessary GPH of fuel flow:
Using BSPH=0.5 for a NA motor, and a constant of 6 i get about 45 GPH, a healthy 50% over what ive got...

Doing the algebra, my little 30 GPH will eventually starve the motor at anything above about 288 HP (at the crank using a driveline loss of !0.8)...

On my motor this occurs at ~3000 RPM according to the dyno curve.

Im thinking i'd better get a better pump?
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