Fuel Pump Requirements

Bill D

New Member
My plan is to use stacked EFI from TWM. I have noticed several posts where 3 pumps are used - 2 LP and 1 HP - and the use of a swirl pot (tank).

Since my intended use for this car is 90% street, can someone provide some useful guidance for a good dual fuel pump setup and where to locate the pumps and filters in the engine compartment? /ubbthreads/images/graemlins/confused.gif


Ron Earp

Staff member
Check with Hershal or other RF owners running EFI. RF provides everything, the pumps, fittings, hoeses, etc. and they do use three with a swirl pot. I'm using Webers on mine or I'd help more. RF for the EFI puts the pumps below the rear sills, that way they are close to the tanks and hidden.
Bill D,

I am just finishing up a carb to TWM EFI 8 stack manifold

change. I am using a single Carter LP pump, surge tank, and

TWM regulator above deck. I have a single Bosch HP pump and

changeover valve below deck, inboard of the right side

tank. This was given the OK, by the tech guys at TWM. If

you decide to go the TWM route, let me know. I learned a

few tricks along the way that will help.


New Member
Bill, Robert and Hershal will be at Knox Berry this weekend with a couple of RFs, so if you can get there you can get first hand information.

I have the FI system with three pumps. The low presure pumps act as transfer pumps to the swirl pot (a seperate section of the right hand tank). The high presure pump pulls from the swirl pot. It is pretty straight forward with the three pump system.
Like Bill Bayard, I am using a single LP pump drawing via a 2-way changeover valve from either tank (filter on each), feeding a swirl pot. From there, a HP pump delivers fuel to the EFI rails (via a final filter). Fuel return from the rails is via a regulator, then to the swirl pot, then back to the tanks via the other 2 ports on the changeover valve.

I am not sure that there is any really big advantage with either approach - dual LP pumps or single LP + changeover valve. The only thing to watch with a dual pump setup would be to make sure that the one active LP pump doesn't just back-fill the opposite tank (perhaps one-way check valves would be needed). The changeover valve approach avoids this problem.

Kind Regards,

Peter D.