Unregulated or Regulated return

madman1234509 · Sep 27, 2013

So with recent topics of fuel systems and returns, i want to know what you guys are running for a return, regulated or unregulated. Maybe also describe whos kit, injector pump set up and nozzle size. Any issues? Surging? Holding rail pressure? Maybe also the theory behind why you did what you did, or why it needs to be regulated. Im doing my own set up on my build and am unsure whether I want to regulate the return or not.

Please only vote if you have done one of the options.

tbsimmons · Sep 27, 2013

All mine have been on gas engines. Regulated return even for dedicated fuel for nitrous. The reason is so the same pressure is at the rails all the time. Dont have solid proof the other way would not have worked but have always put the regulator after the need for fuel.

Morgan@Midwest Diesel & Auto · Sep 27, 2013

Unregulated on all our setups that we are doing. No problems, cooler fuel temps.

madman1234509 · Sep 27, 2013

I can see how, if you keep pressure after the rails, on the return fuel, in theory when you have a high injection duration, at a high rate, and your motor is sucking in the fuel, it almost causes a reservoir and keeps fuel from flowing out of that system when its needed.

tbsimmons · Sep 28, 2013

I am sure it works both ways. I have just seen on nitrous setups that when the regulator is before it can drop fuel pressure for a split second then it comes back. Put it after I have not see it move. The reason is the instant need for fuel. But we are only talking less than 5 PSI, which when running 45-50 PSI it is not that big of a deal.

madman1234509 · Sep 28, 2013

Im going to have a low pressure fuel gauge on my truck after its done. If we dont get a huge dicussion going here, i may try it without it being regulated and watch my frp, and low pressure, if I have problems with either or see an brief drop try regulating it after to see.

CT9AIX · Sep 28, 2013

I have the feed only regulated, but my set up is fairly mild compared to others. Stock nozzles, 1 pump, factory fuel cooler in place with the return plumbed directly back to tank. Fuel temps have been cooler than ever, no surge, no drop in RP.

simonton6.4 · Sep 29, 2013

Mines regulated its Marylands kit but I haven't took the time to mess with it and get it set right to know if its doing anything

Stroked777 · May 7, 2014

Sorry to bring up a old thread. But the point of a regulated return is so that there is a little pressure to keep the fuel from free flowing thru the heads and injectors?

madman1234509 · May 7, 2014

Kind of what I thought. It's a good theory. I put a 2nd regulator on my truck for the return out of the pumps and heads. Its regulated at like 3 psi. The return from that regulator goes through a fuel cooler on the way back to the fuel cell as well.

Stroked777 · May 7, 2014

This is just a wild thought, but is it possible to keep the pressure in check with a banjo bolt that had like a 2-3psi pressure release? Seems more simple than all the lines and what not

Morgan@Midwest Diesel & Auto · May 7, 2014

This is not a 7.3 or 6.0 that feeds injectors through the heads guys. They are a freaking common rail. No regulation is needed on the return, the same for and cp3-4 pumps engines either. You give the pumps 8-10 psi so they have a steady supply of fuel and the rest is history. Nothing to argue about here.

forcefed6.4ford · May 7, 2014

Didnt sleep well Morgan? LOL

Morgan@Midwest Diesel & Auto · May 7, 2014

Just the truth.

Radioflyer · May 7, 2014

Sledpull said:
This is not a 7.3 or 6.0 that feeds injectors through the heads guys. They are a freaking common rail. No regulation is needed on the return, the same for and cp3-4 pumps engines either. You give the pumps 8-10 psi so they have a steady supply of fuel and the rest is history. Nothing to argue about here.

This^

I'm running one just for user feed back and to clean up the engine bay. Will be putting a fuel cooler back on eventually before it gets really hot here (mine is MIA at the moment). Is it neccessary? No, does it cut down the costs of the fuel filters, yes if your running an aftermarket lift pump like a fass, fuel lab, air dog, etc with proper filters

Stroked777 · May 7, 2014

Sledpull said:
This is not a 7.3 or 6.0 that feeds injectors through the heads guys. They are a freaking common rail. No regulation is needed on the return, the same for and cp3-4 pumps engines either. You give the pumps 8-10 psi so they have a steady supply of fuel and the rest is history. Nothing to argue about here.

I know they are not fed through the heads. I'm not an expert on regulated returns and it was a though I had. I know people see a benefit from having son pressure on the return side of the fuel system, and I thought that that some pressure could be created by a pressure relief valve built into the banjos for the return from the heads to create a little pressure to hold fuel back

HOOV3R · May 7, 2014

In a common rail you do not want the fuel to be held at the return for the injectors. The extra fuel that is being returned from the injectors is used for cooling. You want the cooling fuel to be out of there as fast as possible to maximize cooling efficiency.

Stroked777 · May 7, 2014

HOOV3R said:
In a common rail you do not want the fuel to be held at the return for the injectors. The extra fuel that is being returned from the injectors is used for cooling. You want the cooling fuel to be out of there as fast as possible to maximize cooling efficiency.

Well isn't a regulated return doing the same thing? Holding fuel back

HOOV3R · May 7, 2014

Stroked777 said:
Well isn't a regulated return doing the same thing? Holding fuel back

Yes. That is why Morgan and others recommend doing an unregulated return.

Stroked777 · May 7, 2014

I never planned on doing one. It was just a thought I had for people that wanna run one. Isn't there a thread where they discovered seals popping out on the hpfp due to regulated returns?