OK i have a p1sc that i am about to install. my question is will my 110 GPH Holley mech. pump be enough to feed it at 8-12 PSI? it is a carb car and i do have a holley red electric pump also. I will be running an 8# pulley on the street and a 12# at the track. would it be a good idea to run the pumps inline? and run the electric to a switch so i only use it when i need? or should i ditch them both and get bigger electric?

thanks

Colt

 

Anyone????

 

No one can answer the question because both you and Holley didn't provide enough information about the setup.

1) You need to know the flow (GPH) of that fuel pump at 6 PSI(carb setup) + 12 PSI (boost setup) = 18 PSI. Holley doesn't give this info. They only give a general "who knows" PSI for the 110 GPH they advertise. Call them and ask what it flows for GPH at 18 PSI.

2) You listed a max. boost of 12 PSI but never stated your estimated HP. Suppose you have 350 HP without boost. Then at 12 PSI you will ROUGHLY have 635 HP if your IATs are kept in check. You will need a pump that flows ((635 * .57) / 5.8) * 1.2 = 75 GPH at 18 PSI of fuel pressure.
That is for a general 350 BHP boosted engine using 12 PSI with a 20% safety margin for the fuel pump.

Call Holley and find out what there pump flows for GPH at 8 PSI and 20 PSI of fuel pressure. I would guess that at 18 PSI that pump will not be enough for a 350HP engine with 12 PSI of boost.

 

Ok a little more info. car is a 383 with around 410 BHP.

If i get a bigger electric pump. say a 255 LPH pump and run it at 18psi, do i need to run 18 all the time where its a carb car or only under full boost? and if i only need to at 6 when not in boost but 18 at boost how do i accomplish that? FPR?

thanks

Colt

 

yes with a FPR that had a vacum line to the manifold that when it reads boost it bumps up fuel pressure. they 1 to1 ratios all over the place. for every pound of boost it reads it increases the FP by one. so if you have FP set at 8 and hit 12lbs then it will uip you FP to 20lbs when at full boost. hope this helps

 

easiest thing to do is to go boost ref. machanical. with a carter super strip, good to 16 psi, look on the turbo forums