Regulated Return Pressure

Sixfoh · Jun 17, 2020

Ok so I have done a fuel bowl enhancement on my 6.4 which is to supply both hpfp's and regulated return fuel pressure. As far as I know the stock fuel bowl regulates return pressure to 3 psi +/- 0.5 psi. So my questions is if I should set it to the stock return pressure of about 3, or higher to be similar to the supply pressure of 8-10 psi?

Sixfoh · Jun 19, 2020

akf250 · Jun 19, 2020

I am wondering the same thing. Is there a test port or do you just put it a pressure gauge inline?

sootie · Jun 19, 2020

Why would you want pressure in the return? It's not like a heui system ...

White_monster · Jun 20, 2020

We have a terminology issue here. The fuel bowl ****** is regulating the return circuit of the fuel. Its regulating the system pressure not the pressure in the return line. This is called regulated return.
Set the system pressure to 8-10psi.

Sixfoh · Jun 20, 2020

Ok thanks for the information. I did kind of get the ideology mixed up in how this works. So to be clear a regulated return is taking the fuel supply, regulating it to the desired psi and dumping off any excess fuel? Just some side notes. RCD had suggested 6.5psi but said the lower you could get it the better. Also curious why the factory fuel bowl regulated the pressure to only 3psi. I certainly dont wanna starve my pumps. Was mostly worried about a volume to psi difference. Since they often work inversely.

sideactiondiesel · Jun 20, 2020

RCD had suggested 6.5psi but said the lower you could get it the better. Also curious why the factory fuel bowl regulated the pressure to only 3psi. I certainly dont wanna starve my pumps. Was mostly worried about a volume to psi difference. Since they often work inverse

Hmm never heard of them.

akf250 · Aug 28, 2020

I have a FASS 165 Pump with a Elite Diesel Fuel Bowl D3L3TE Kit and a Stock Fuel system after that.

I finally got a gauge hooked up to my fuel system to check system pressure. I plumbed the gauge into the front of the fuel bowl D3L3TE kit block (where the temp sensor goes) and key'd the truck on.

I was sitting at 4.5 - 5 PSI

We spun the nut on the top of the Aeromotive Fuel Regulator IN and were able to attain a system pressure of 6.5 with a spike to 8 when first being key'd on.

As far as I can tell the Fuel Regulator is maxed out.

How are you guys obtaining 8 - 10 PSI of system pressure? Different springs in the Low Pressure Fuel System? Different Low Pressure Fuel System all together?

I am trying to fix a issue I am having with my fuel pressure dropping rapidly under launch (4 wheel launch, burnouts, dyno hits, etc.)

No issues while driving at speed and doing WOT hits (even while towing) - holds a constant 26,000+ FRP when doing hits at speed.

Ran injector contribution tests alongside this and had one injector running +8 at times, the rest were withing spec.

White_monster · Aug 28, 2020

akf250 said:
I have a FASS 165 Pump with a Elite Diesel Fuel Bowl D3L3TE Kit and a Stock Fuel system after that.

I finally got a gauge hooked up to my fuel system to check system pressure. I plumbed the gauge into the front of the fuel bowl D3L3TE kit block (where the temp sensor goes) and key'd the truck on.

I was sitting at 4.5 - 5 PSI

We spun the nut on the top of the Aeromotive Fuel Regulator IN and were able to attain a system pressure of 6.5 with a spike to 8 when first being key'd on.

As far as I can tell the Fuel Regulator is maxed out.

How are you guys obtaining 8 - 10 PSI of system pressure? Different springs in the Low Pressure Fuel System? Different Low Pressure Fuel System all together?

I am trying to fix a issue I am having with my fuel pressure dropping rapidly under launch (4 wheel launch, burnouts, dyno hits, etc.)

No issues while driving at speed and doing WOT hits (even while towing) - holds a constant 26,000+ FRP when doing hits at speed.

Ran injector contribution tests alongside this and had one injector running +8 at times, the rest were withing spec.

I'd guess some trans slip would be the issue. But to up low pressure fuel system pressure you need to increase the pressure the lpfp puts out.

drdiesel · Aug 30, 2020

I have the rcd regulated return for the fass setup and was able to just run one straight hose from fass to kit. And it was half the price of some other kit out there.

sideactiondiesel · Aug 31, 2020

And it was half the price of some other kit out there.

Hell yeah thats awesome. You can probably buy Their stuff at walmart as well.:flush:

Shafer171 · Aug 31, 2020

Lmfao

akf250 · Sep 11, 2020

Does it make sense that when I raise system pressure at the regulator (tighten the adjustment screw on the regulator) that my Fuel Rail Temperature rises?

I put the screw in and it immediately changed my fuel rail temps. Normally they were around 100 degrees, never going above 120.

After I adjusted the regulator it immediately put the temps to 150+

I backed the screw out a turn at a time until it went back to a stable 104

More fuel circulating through the fuel rail and less fuel returning to the tank = higher temps I assume?

White_monster · Sep 11, 2020

Higher pressure higher temps. You have two regulators in your system. Putting any fluid over relief, what your regulator is set to, will create heat. My fuel temps once up to operating temp is 140f depending on ambient temp.