Title pretty much says it all. Have a mechanical gauge hooked up and am currently pushing about 72psi. Any problem with that?

 

Though all trucks do not react the same to increased fuel pressure, I found that anything above 66 psi caused my mpgs to go down some. I currently have mine regulated to 62 psi with an adjustable regulator. It seems to work well there and I haven't experimented with any other pressures since it was lived tuned with 62 psi.

 

What Roland said. I wouldn't go over 65 myself and am currently running stock at around 58.

 

Hmm, so the higher pressure caused mpg's to decrease, interesting. Thanks Roland. I re-did my in-tank mods this past weekend and added the stainless line to push the returned fuel away from the pickup foot. The 5/16" stainless tubing I used has a bit narrower inside diameter than the stainless tube going back into the tank. This MAY be the cause of my increased pressure. And it does seem like my mileage has been bad this tank.

 

Crap, please don't tell me I have to drop my tank AGAIN!

 

Is there anything I can do to decrease the pressure other than removing the stainless return line I just installed? I like having it in there.

 

72 psi of fuel pressure isn't going to hurt anything, and it's not going to hurt mileage.

 

How much smaller was the I.D. of the tubing? I guess you could take a little off the regulator spring. You use the stock spring when you do the FRx, don't you? I could mail you my old one, if you want to experiment.

 

You don't.
Fuel pressure is controlled at the pressure regulator.
It's the same as amps and volts
Fuel pressure is the volts and fuel volume is the amps.

 

Bob at Diesel o-rings has a regulator with three different spring tensions. Not sure if he'll do it but maybe he could sell you just the springs. Each one is a certain PSI.

 

I'm doing a lot of searching now and was just reading up on installing a helper pump. Would doing this increase the volume of the fuel and make it easier for the stock pump to maintain the increased pressure? Thanks a ton for the help guys. I have been experimenting (for lack of better words) with my in-tank and prepump mods because I am still getting a little air in my fuel (that I can see in my clear prepump filter).

ETA : I should add that I am very hesitant to remove the FRx at the FPR because when we added this mod at RRE we stripped the threads on the FPR and had to tap the holes and use bigger bolts to get everything re-installed. Everything is sealed up right now and I'm afraid that if I mess with it too much it will cause a leak or something.

 

When I installed my Walbro, I got an increase of fuel pressure to ~100 psi. I had to go back to the stock housing and spring, from my DI shim and housing. The DI fpr housing had multiple holes, instead of one large opening, and created a restriction on the return side due to the increased volume of fuel. I still had ~ 72 psi with the stock parts. I drilled and tapped the DI fpr housing to accept a fitting and plumbed an adjustable regulator.

 

I hear ya. I have the helper pump on mine also. It may be what is contributing to an even higher volume of fuel and increased pressure. It may just aggravate the problem by adding an additional pump. My adjustable fpr allows me to compensate for the the additional fuel and bring my pressure in line.

 

So, you have a regulator on the return coming off of the FPR, but not a true "Regulated Return?" Or am I just being redundant?

I would like to hear more about your setup. Essentially I am trying to increase volume and decrease pressure, but I'm not exactly sure how to do that.

I was even looking at Dan's in-tank pump, but that may be a little over my head.

 

Pressure and volume are indirectly proportional to each other. If you increase the Area the pressure will decrease, and if you decrease the area of the applied pressure, the pressure will be automatically increased. So, pressure is indirectly proportional to area.

So basically, adding a helper pump will only drive your pressures higher. Rather than making things more complex than needed, I would just take a small coil off your spring in the FPR or correct your intank return tube sizing. By adding a restriction in the tank it can over come the FPR and become the regulating system instead.