I just got an Aeromotive FPR and fuel rails. I will be running -8AN feed and -6AN return lines. My question is what is the best way to plumb the fuel rails and FPR?
I have seen it done a couple ways.
1) Feed line to FPR then out of FPR to fuel rail and capped at the end of the second fuel rail.
2) Feed line directly to Fuel rail, through second rail and then into the FPR.
Which one of these is better? Is there another option I am missing?
I would think having the FPR after the rail would keep the pressure more stable.
Here is my ghetto diagram:
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'71 Chevelle - LS1/T56 swap - On the Street!!
#2 is a better setup and is how mine is run except I've got -8 going both ways. It'll provide more stable fuel pressure especially if you plan to make a lot of power. BTW, if you want a nice place to mount yoru fuel pressure gauge aeroquip makes a nice 3/8" NPT to -8 fitting that has a 1/8" NPT port coming off the side so you can mount your gauge on the front of one of your fuel rails.
One more good thing about option #2.. is the continues flow of gas through the fuel rail will also keep the fuel rail cooler resulting in a deleivery of a cooler charge of fuel. May get you a few extra..
My system is hooked up like the first picture. My pressure seems to be pretty stable that way.
__________________ 85 Monte Carlo SS, 5.3/4L60E Daily driver
84 Monte Carlo SS, LS3 418, 248/254 615/595 with XER and XE lobes. AFR 225, 1 7/8 Hedman headers from BRP. 200-4R. 9" Ford, 3:50 gears.
Don't forget the recommended way (from Aeromotive, anyway): pump is supplied via Y to both fuel rails, then both to the regulator, then return to the tank.
There have been several reports of this causing a slow rise in tank fuel temperature (due to engine heat being transported back to the tank via the fuel); eventually causing vapor lock. But this method is the best way to assure stable fuel pressure at the injectors.
Don't forget the recommended way (from Aeromotive, anyway): pump is supplied via Y to both fuel rails, then both to the regulator, then return to the tank.
There have been several reports of this causing a slow rise in tank fuel temperature (due to engine heat being transported back to the tank via the fuel); eventually causing vapor lock. But this method is the best way to assure stable fuel pressure at the injectors.
jp
what exactly vapor locks? i've had extremely high fuel temp but not sure of vapor lock?
Gasoline turns to vapor at around 130 degrees F. If your fuel gets that hot, it may disrupt the pump's action since it is designed to pump liquid, not vapor.
I am not familiar with the Aeromotive FPR, but be careful. The option 2 requires a "return" regulator, which is very different from either a bypass regulator (option 1), or a traditional in-line supply type regulator. I'm sure if you follow the manufacturers recommendations, you will be fine.
Aeromotive regs can be run both ways, the suggest option 2 is best but you can run them like option 1, mine is an aeromotive 13109 reg and I run it like picture 1, with constant 58psi supply.
Gasoline turns to vapor at around 130 degrees F. If your fuel gets that hot, it may disrupt the pump's action since it is designed to pump liquid, not vapor.
jp
How often does the gas in your tank reach 130 degrees? That is what the fuel pump is pumping. If the gas in the rail turns to vapor I would think that the injectors could handle that, in the old days carbs could not.
Jim
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57 Belair LS2/T56/Dana 44
2003 Harley FXD
2000 CLK430
I had a friend tell me that this regulator has to have vacuum reference hooked up to be adjusted and work correctly.......aeromotive told me, if my setup originally had vacuum reference to hook it up, but if it didn't.....don't hook it up. My setup is 6.0L/L92 head/02' camaro computer, L76 car intake with single fuel rail inlet. I was gonna hookup like pic #1......do I, or do I not, need to use vacuum reference on the aeromotive 13109 fpr?
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I have used the Aeromotive regulator without vacuum and the pressure was steady from idle to WOT.
__________________ 85 Monte Carlo SS, 5.3/4L60E Daily driver
84 Monte Carlo SS, LS3 418, 248/254 615/595 with XER and XE lobes. AFR 225, 1 7/8 Hedman headers from BRP. 200-4R. 9" Ford, 3:50 gears.
Increasing the pressure at the rail increases the effective lb rating of the injectors. For example SVO 30 lb injectors are rated at 30 lbs for ford vehicles but act more like 36 lb injectors at the gm fuel pressure. Of course there is a limit to how much you can crank up the pressure.
Does anyone have a part number for this? I want to mount mine on the fuel rail on the vette.
Quote:
Originally Posted by Skele4door
#2 is a better setup and is how mine is run except I've got -8 going both ways. It'll provide more stable fuel pressure especially if you plan to make a lot of power. BTW, if you want a nice place to mount yoru fuel pressure gauge aeroquip makes a nice 3/8" NPT to -8 fitting that has a 1/8" NPT port coming off the side so you can mount your gauge on the front of one of your fuel rails.
Fuel pressure regulator plumbing? 
aeromotive 13109 fpr question 
