I can see putting a regulator in a system after the pump before the filter or for that matter any where you want on a dead head system. A fuel system with a return line that returns past all your injectors with out some sort of restriction such as a orfice, set check valve or a adjustable regulater would flow to tank without building a pound of pressure. The amout of area for the return with a return system is the same or greater than the supply. Be the same as returning the fuel to the ground if it was in the supply line before the injectors. There would be no way to control the leak.

 

Regulating after the injectors tells us that the highest drain point (last two injectors) are still getting the minimum fuel pressure required. Regulating in front of it tells us we have no clue what the last injectors are getting. Unless of course you're reading fuel pressure behind the heads.

To address your starvation theory, why is it with my fuel pressure gauge behind my heads, I drop down to 25psi on full throttle runs with something even like a mild street tune? I bet with my fuel pressure gauge up on the bowl, I'll be at 55psi.

 

Bernoulli's principle/equation, the science that all flow is based on, states that if pressure goes down, volume must go up. If you are 55 psi up front and 25 psi at the rear while you are on the load pedal, would have to say that the volume has gone up to meet the demand. I see a whole lot of energy spent arguing about pressure, but I see very little addressing volume. Fact is, because the two exist in opposites, it's pointless to discuss one without the other.

I have run hydraulic test stands at 3000 psi on F/A-18s and watched 500~700 psi drops when the flight control actuators moved. Demand was placed on the system, pressure went down, volume went up and work was done. This is very similar to what's going on in the fuel system that we are beating into the ground.

To put things into perspective, 55 psi is 84% of 65 psi and 2500 psi is 83% of 3000 psi.

 

Yep pointless your right if I was you I would regulate at the filter housing with a return system.

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The 6.0 liter ford is the same as a FA-18

 

It's called fluid dynamics and the principles of operation are the same regardless of whether it's water, hydraulic fluid, or diesel fuel.

 

I follow you Karl, a lot of people focus too much on static pressure and not dynamic pressure. My pressure dropping tells me my pump can't keep up with the volume needed to sustain 60is psi at a given RPM. That wasn't my main point though, I'm trying to make the point that readings in front of the heads are different than readings in back of the heads. My fuel pressure reading with nothing more than a mild tune on a new stock fuel pump, upgraded blue spring, and brand new fuel filters (the old style without the o-ring to boot) drops like a rock when I'm on the skinny pedal. This is reading behind the injectors. Everyone else I know with similar or even bigger setups who reads in front, sees their pressure as just fine...

That is why Dennis wants to regulate after the injectors, you're basically regulating at the end of the system, not 1/2 way through.

I think we're looking at the regulator the wrong way, or not on the same page. It seems to me that the pressure from the pump to the regulator is regulated, and after the regulator it sends the excess fuel back, that's the only way I can see it working behind the heads like that. If that's the way it did work, and it was in front of the heads, you'd really have no idea what your pressure is going to those last injectors. We've already proven a pressure does not equate to a volume...

 

And a Jet runs a gear style pump for its functions. Not PC, LSPC System? I'm not doubting you and I can tell you are one to never be wrong! Pretty sure this 6.0 liter diesel with a return system is no where in the same principal as a FA-18 hydraulic controls. Let me know when you plumb you fuel system like a FA-18 I would sure like to know the results.

 

Ya know what, this is going NO WHERE FAST! Mike, I kind of see where you're going about looking at the regulator backwards, but you have still yet to expain why path of least resistance wouldn't eventually hurt the system. We thought that Gillette spring was harmless, but now I am having second thoughts because of the LONG TERM EFFECTS.

My opinion is: I don't like the way these regulated return systems look/function, I don't care who's name is on it, they all essentially work the same. Until I find something better than what is on the truck now, like the AD100/HCFM Heavy Assault uses, it's staying the way it is.

Peace out.

Bernoulli Principle Animation | mitchellscience.com

Play with this for a minute, it's a neat interactive tool to help explain fluid dynamics.

As far as never being wrong, Mdub can tell you most certainly that not only have I been, I can F#$KING ADMIT IT.

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For the record, an F/A-18 hydraulic system consists of a reservior (tank), a pump, pressure relief valve (regulator), pressure and return lines, filters, and an actuator (or injectors for this comparison). Yes, it's basically that simple.

Hmmm, what does that sound like? Oh yeah, A 6.0 FUEL SYSTEM!

 

Well Einstein you are a true hydraulic specialist! The only thing, the injectors on the fuel side are nothing more than a controlled leak. You ought to go back to you instructor and discuss this with him. Im done talking about your comparison to your jet,

 

Not sure why everyone is getting their panties in a wad.

Karl, I'm not making known statements here, just talking it over with you because I'm trying to grasp the whole thing myself. Honestly I'm not really sure how the regulator works, I've never really played with one. Just bouncing ideas off of you.

What do you mean path of least resistance? I guess I didn't follow that one?

I understand full well how the stock system works and how most of the add on's work, but I've never really had my hand on one of these regualtor systems to fully understand it.

Now, my vegistroke is internally regulated. It sucks fuel from the tank, to the pump/filter area, and the return is right there (similar to stock), except mine is adjustable by a couple turns of a wrench and it then sends fuel up to the heads, and "deadheads" (sorry karl, don't know how else to explain it ) at the front of the heads using check valves. It's exactly how I think it shouldn't be done. Unfortunately using two separate fuel systems, feeding in from opposite ends of the heads, and using check valves to stop the flow going each direction, means adding a RR is going to be a major PITA with tons of extra valves that I don't want the headache of.

As for the RR, Dennis designed it and did a bunch of research and readings on the Ford systems trying to figure out how to maintain a minimum pressure to all 8 injectors. He definitely doesn't seem like he's trying to pull wool over anyone's eyes so to speak, I'm just trying to understand the whole system, and I'm a visual kind of guy. I need stuff in my hands to really understand it unfortunately.

No hard feelings here guys, just trying to learn like the rest of you!