Take a look at the Holley 12-1800 pump. It's a compact twin pump that flows 530lph and is rated for 18 volts and E85 use.

 

If you drop below the OEM reg pressure it will shut completely and the siphon will cease to operate at all. Yes, under vacuum pressure goes down, you would have to run at least 10-15PSI above the factory regulator to insure it will not shut under vacuum. This is different from the worries other people have about running low fuel pressure and the siphon working. They have a flow through in place of that regulator that constantly flows.

Also, I doubt that pump will handle 1200whp on its own.

Why would you tee the factory pump into the return line? That makes no sense.

 

To clarify this - only one regulator in the stock C6 fuel systems controls engine pressure and that is in the driver side primary fuel pump module module. The electric fuel pump itself also has a relief valve if an overpressure condition exists but that isn't a regulator. The passenger side regulator only impacts the operation of the jet pump/venturi pump. If pressure drops below the passenger side regulator pressure, the jet pump stops flowing fuel. When the jet pump is flowing fuel the pressure in the jet pump is controlled by the driver side regulator (main system pressure).

 

Not quite, they both connect directly to the output of the pump, the siphon doesn't come from through the driver side regulator. It goes pump output into a collection chamber with a small filters, than theres a line that goes from that to the driver side regulator which dumps directly back into the bucket, then there's another line that goes to the passenger side reg and siphon, and then theres another that goes to the front of the car. There's actually one more small one that runs a small siphon on the driver side as well.

 

I would hardly call it a half cocked rant, and in fact it is quite apparent from your contradictory statements you may be the one who needs to do some research before you go jumping down people's throats. What I posted was the typical and preferred EFI regulator installation for an aftermarket return style system. If you are too lazy to do some research I can post up some Fuelab, Aeromotive and Weldon diagrams on how to plumb a fuel system for the OP if he is confused by the useless back and forth in this thread. If you want to dump some more of your CARB or returnless regulator info though feel free.

 

I never said anything about which was more preferred, that's your opinion and you are fully entitled to it. I only made a comment about which is more common. I also did not contradict myself. Go ahead and call any of those guys and ask them if it's ok to install their regulators pre fuel rails. They will all give you the exact same response I did, it's perfectly fine and the only pressure difference will be from restriction of the lines so make sure you size them appropriately. Putting the regulator right at the fuel rail will limit the possibility of any pressure differential but is completely unnecessary if your lines are sized correctly.

What I replied to was your comment that it's the ONLY way you should install a regulator and why doing it the other "wont work". Which was completely wrong and inaccurate.

Again, this is complete BS and doesn't happen, it's not how a fuel pressure regulator works and I honestly can't begin to imagine how you came up with this in your head. This isn't how a return style regulator works, OR a deadhead regulator, or even a fixed orifice limiting valve, or any other kind of regulator I can think of. Again this is how a pressure referenced return regulator works, exactly.

You're simply wrong, but go ahead and dig yourself deeper and try to explain the bolded explanation.

 

If you replace the passenger tank regulator with an LPE block off which has small holes drilled into it, you can lower the base pressure even to 20 psi and the siphon pump on the drivers & pass side will work just fine.

I've bench tested the system at 20 psi and the pump works just as good at 20 as it does at 60 psi, just an fyi

Stock form it wont work because the stock regulator on the PASS side will close, but you take that regulator out and replace it with an LPE block off and you can run low pressure no problems.

Also... on side note, the stock pass regulator does control pressure 100% as well as the driver's. (example, with LPE block off on pass side, the system will NOT hold any pressure with pump off since it is a static fixed block with holes, so starting your car will take a few more cranks which is okay)

Pump feeds a bucket where the filter sits in the stock fuel module, that bucket then has a fitting that runs to driver's side regulator, and another fitting that runs directly to passenger side regulator. Both regulators are preset to 60 psi or so.

http://www.lingenfelter.com/mm5/merc...=#.UYE980qRd8E

 

I put an external 255lph Walbro off the drivers side tank and an external regulator set to 58psi on my LS3 car. Since I'm not using a vacuum/boost referenced regulator, I shouldn't need the block offs right?

 

You are correct on the MP4302 pump not being able to handle that level of power but the MP4301 or 4303 would work just fine, and the reason I had mentioned running the factory system into the return line on external regulator is that it would keep the stock system functioning but basically just being used to syphon fuel from one tank to another. As i type this I am contemplating just biting the bullet dropping the tanks installing the block offs and a walbro 450 pump inside the basket, and leaving my secondary fuel that I have now.

Ya there is no need to install the block off plates unless you are wanting to go to a boost referenced fuel system.

 

If you had a checkvalve in place it should, but also your regulator might be leakign down. I know a lot of aeromotive regulators don't hold pressure with the car off.

However, the pas regulator doesn't really "control" pressure, since the siphon jet is a very small orifice, very little flow is able to actually go through, so it's not able to actually regulate a high volume. It is not however hooked inline with the driver side regulator, it's it's own circuit. I think you knew that already, but the way you typed it was ambiguous.

Should work as long as that is indeed when that regulator is opening.

I see what you're saying now, you're talking about running the stock pump to only function as a siphon and have it dump back into the tank instead of supplying the engine. That won't work either. The return line of a return style system is NOT PRESSURIZED. You need the 58+ psi of pressure in order for the siphon to operate with the OEM regulator in place. You would have to return the OEM pump through an addition regulator set to a static 58+PSI into it's own return into the tank. Now you're just making things ugly and defeating the purpose of your design in the first place (to be simple)

Additionally return lines are very sensitive to pressure changes (this is why it's actually often recommended to have a larger return line than supply line for the best pressure control).


Just FYI I have nearly the same as what you're trying to do, except I have the blockoffs and flow through regulators installed in the tank and my OEM supply is teed into the output of my secondary pump.

 

The passenger side and driver side regulators are not the same pressure rating. If I recall the passenger side regulator is about 30 or 50 kPa lower in pressure rating (350 vs 400 or something like that).

Also the passenger side regulator acts more like a check valve. When system pressure drops below a certain level, no more flow goes to the jet pump. This keeps the system from dropping pressure when you shut off the vehicle since the jet pump would be a leak and the system wouldn't hold pressure. Think of the passenger side regulator as being a pressure regulator with the return feed/discharge being to the jet pump.

Also, as someone else already pointed out, all of the bypass/return flow from the passenger side regulator has to flow through the jet pump orifice so it can only leak so much flow/pressure. The orifice size is fairly small so only a small volume/mass of flow can flow through the orifice, even at fairly high differential pressures.

Our passenger side regulator eliminator block allows the passenger side jet pump (that transfers the fuel to the driver side) to work at pressures below the normal passenger side regulator pressure. This is needed if you run a vacuum referenced fuel system or a system pressure that is below the passenger side regulator pressure (otherwise the passenger side jet pump won't operate). When you are using our passenger side regulator eliminator block it is assumed you are using an external regulator with a return line and check valve so that you can still hold pressure on key off.

 

Is your replacement a pass through, or is it actually a regulator that just opens at a lower pressure?

 

Yes that's what I was trying to get at.

I realize the regulator is slightly different, and yes if you use an external check valve after the stock pump you will hold line pressure between the check valve and fuel rail.

I like the less fittings the better, my fuel system I designed actually holds pressure, has no external check valve and still holds pressure key off ohh and its all in tank. I'll post pics of how I did mine.

 

I came up with this because that's how they work. I don't want to argue with you, I just want to make sure there is no false info out there for the new people. They are ball and seat type reducing valves with the ball operating off of diaphragm action. The diaphragm controls the distance that the ball is from the seat, which controls the amount of flow bypassed to set the correct upstream pressure. You raise the base pressure (upstream pressure) by adjusting tension on the spring forcing the diaphragm down and subsequently the valve (ball) closer to it's seat. Under vacuum the diaphragm is allowed to lift and be overcome by EXCESS pressure (below the preset value adjusted by the screw in the top of the FPR). When a car comes into boost it is allowed into the reference port and (with a 1:1 spring in the FPR) causes the ball to move closer to it's seat restricting downstream flow so that upstream pressure (whatever the pump is required to produce) is at the correct level so that the d/p across the injectors is the same as it is at idle.

As for me saying "preferrred method" I mean it's the only recommended method for a return style boost referenced fuel system. Feel free to call any of the aforementioned companies or kinsler or any other reputable/knowledgeable person if you want further clarification.

When I said contradictory statements I was referring to you saying they don't use any kind of orifice or limiting device (which they do as you can order replacement parts) then the next sentence you said they do use a orifice?

 

Return style regulators do not "restrict" through-flow to affect a pressure change. PERIOD.

If I make it huge will you actually read it and figure it out? look, you're wrong and this is getting so stupid. Go take apart your regulator. This is the last time I explain the same thing over again. The inlet and outlet of the regulator are not limited from each other, it is a straight through shot. The orifice is on a tee NOT inline. The pressure going into the regulator is exactly the same as the pressure going out. I understand this is hard for you to wrap your head around but it's a fact, you can test it if you would like. The regulator only bleeds excessive pressure.

Believe it or not the only difference between the pressure at the pump outlet in the rear of the car, and the pressure at the fuel injector is whatever the pressure drop of the line is.




Again, like I said, putting the regulator as close to the fuel rail provides the best possible pressure control. That's because it eliminates any variances from the pressure drop of improperly sized hoses. I could go into excruciating detail on this, but seeing as you can't even understand how the regulator works in the first place, I am not even going to bother.

The important thing to this point is it's completely unnecessary to place it after the fuel rails if your hoses are sized properly. The reason for doing this is to eliminate any variance in control pressure from pressure drop.

I never said anything of the sort, I said

Like I have gone over AGAIN at the beginning of this post, there is no limitation of flow "upstream" or "downstream" of the regulator, it's a straight through shot. period.

 

LMAO I get it now, you have it hooked up wrong. If you are using a 3 port regulator, the two ports which flow together with no restriction are both inlets, maybe you should read the instruction manual. This **** is comedy gold.

 

Direct from Aeromotive

 

Who are you trying to fool? You have dug yourself so deep trying to save face, now you are just trying to lie.

He wont link the actual install instructions because it says exactly what I have. By "optimum performance" they are referring to what I already talked about with the possibility of pressure drop through restriction (wont happen if your lines are sized properly). http://aeromotiveinc.com/wp-content/...3101-09-14.pdf

 

If anyone is wondering, the pressure drop through 5 feet of -10 line at 900lb per hour (Around 1kwhp of flow) is approximately .1 psi....

 

Dude read the instructions of what you just posted.