aftermarket fuel pressure regulator return line or not

[cumminsfarmer]

I have sumped the tank I have 1/2 line a fass 95gph pump I got for free. I want to run a boost referenced fuel pressure regulator . my question is should I run one that has a fuel return line or not? Its raises fuel pressure 1psi for 1psi so I'm thinking about running a bleeder on the boost line to bleed air off so I can get .25-.5psi of fuel per pound of boost. Any help is appreciated I tend to ramble when it comes to first gens

[PToombs]

Why not just get the 15psi spring for the FASS and not use the regulator?

[cumminsfarmer]

I'm wanting to keep case pressure up in the pump in the higher rpms . so was thinking raising fuel pressure with boost I may be able to keep it close to 15

[PToombs]

Pressure drops because of lack of supply. The FASS should supply plenty if you have a big enough line to the IP. They usually come with 1/2 inch lines if you get the kit, so that should be plenty of fuel.

[BC847]

It has been my experience that, yeah, you need a bypass type regulator so as to ensure a constant/minimum flow of fuel through the electric fuel pump as that flow is what cools the pump's motor. And, you need to size the return line just as large as the supply line as a minimum. One size larger would be ideal.


- My OEM fuel pickup module is somewhat modified.
- I've a Walbro 392 pushing from the frame-rail next to the tank's pickup, into the OEM fuel filter in the head, into an Aeromotive boost referenced bypass type regulator, and finally into the IP.
- All the fuel supply plumbing is 6AN (3/8" ID).

At one time, I had the regulator's bypass return line simply Tee'd into the stock/OEM return line (5/16" OD).

- It supplied fuel just fine at the time. The problem was; At WOT, if I side-stepped the throttle, fuel would spit from the regulator's case O-ring (a result of the spike in supply pressure when I quickly got off it).



To fix that, . .. now . . .

- I've a 6AN return from the fuel pressure regulator's bypass.
- I've a 4AN return from the IP.
- I've a 4AN return from the fuel injector's return rail.
- The above three returns play into a small aluminum fuel manifold (adjacent to the battery).
- The above manifold has an 8AN return headed back toward the fuel tank.
- Just ahead of the driver's rear tire, in the fender space, there's a fan assisted fuel cooler. (IIRC, it's actually 10AN bushed down to 8AN).
- The above plays back into the modified fuel pickup module (8AN).

No more fuel spitting from the regulator.

[cumminsfarmer]

Thank you! Ordered the regulator with return line. Hopefully get it all together soon as I get intercooler piping