OK guys , I have a question. First I will tell you what I did. My stock lift pump was pushing 12-10-2 so I bought one from Cummins and put it in along with a purolator fuel pump rated at 4-6 psi 35 gpm. With this set-up my pressures were 18-12-6. I dis-assembled, cleaned and re-assembled the old pump. I then made a bracket to mount the pump inside the frame next to the fuel tank, and used the stock wiring to trigger a relay. I put the used one back at the motor and the new pump by the tank, running 3/8 fuel hose where I cut the hard line by the tank, to the engine mounted pump. I took it for a test run and here are the numbers: 32-29-22 ( 22 psi @3k rpm uphill acceleration.) Oh and by the way, my gauge is a 0-30. Is this gonna be too much for the VP44? Could I use a regulator or should I remove 1 of the pumps?

 

The amount of pimary side pressure a VP44 can handle varies by the condition of the delivery valve and the stator. You will get a hard start condition when the pressure is too great. Some guys have made claims that they can spring leaks, but I have yet to see that happen.

I have run them with a V-10 gas in-tank pump pushing over 50 psi, and never had a problem. Then I install a FASS with 26 psi and have to back it down on a different rig. I figure try what works, and if you run into problems, then drop the pressure and try again.

 

OK, what would be the best way to drop the PSI? Where and how bad are these leaks? Are we talking about blowing seals inside the VP44 or just seal washers on the banjos?

 

As long as the minimum pressure of 5 PSI is being met I would say it's good!

On that setup you got I would add a fuel regulator and set it for about 15-18 PSI and see if you can met the minimum 5 PSI at WOT. Then you would be set and be able to keep the VP44 happy with a good constant flow of fuel without the extra pressure.

 

UPDATE: I left the engine mounted pump on the engine, but disconnected the wire and the fuel hose from the banjo at the fuel filter housing. I then disconnected the fuel hose from the frame mounted pump, and plugged both ends of the engine mounted pump hoses. I ran 3/8 hose from the frame pump straight to the filter housing. I am back to the 15-13-8 ratings. I would like to find a regulator, I would like to be around 20-16-12. At least now if my psi drops, all I have to do is re-hook the engine pump to the circuit.