I'm just trying to understand how these boost-referenced aeromotive regulators work. Do you just set the fuel pressure at the desired level, then when the boost kicks in, the fuel pressure rises a bit? If so, about how much?

 

I belive its 1:1 ratio, so for each # of boost fuel pressure rises 1 psi

 

Yep, exactly. Set the base pressure and connect the reference port to a vac source and you are good to go. When pressure rises in the intake, it goes through the line and pushes down on the top of the regulator. The regulator doesnt know the difference in you tightening the screw and boost forcing it down...they do the same thing.

For instance I have mine set at 50psi base, and at 8 pounds of boost my fuel pressure is 58lbs...

The reason you have boost referenced regulators is because when there is boost in the intake, it is forcing itself against the injector. At 10lbs of boost your 50psi injectors just turned into 40psi injectors, so you raise the actual fuel pressure to 60psi to maintain the injectors at 50.

 

Wow, this is some great info. Thanks guys. BTW, my plan is to make about 600+ with an LQ4. Would AN-6 feed line from the tank to the rails be big enough?

 

Stock fuel lines from my intank to my Reg. in the engine compartment and im 600 Flywheel horse.

BTW if you are going to buy a regulator or any other fuel components get them from Lonniesperformance.com

He is a tech sponser and KNOWS his stuff on these LS trucks, he hooked me up with a fuel labs boost ref. reg and fittings and was a big help on the phone, great guy.

 

on a 2001 with factory return and puel pressure regulator, what are the turbo guys using for a boost reference regulator...ive read on here but could be mistaken than we dont have to add one as the factory one is good for low boost, say less than 10psi?

im trying to do a very simple setup with an inline 044 bump and hotwire kit, but do i need to purchase a FPR

 

i have a mallory fpr but i do not use the boost reference, if you have a fuel pressure gauge you can keep your eye on it and make sure u dont get under 60 psi, my tuner dosent use it because of the complexites you run into... when the truck is under vacumm it actually will pull fuel and when its under boost it will add a 1:1 ratio....I have had good success with this *Had to edit* Both ways will work basically tuner preference

 

I am over 600 hp( via efi ) and am running on stock rails, fuel lines, reg with out a issue.. All stock stuff should be fine for this, up to 8xx hp with out a issue..

 

I make 600+whp, and am still on the factory return. Technically it is a boost referenced regulator. At idle mine sets at 60psi, and at 16# of boost it is at 78psi. It was very consistent while I was watching as it was being tuned on the dyno.

 

Umm, not quite. Boost referenced FPR's dont work the same way in vacuum as they do under boost. Think about what you said for a minute, if it were true there would be no point in setting regulators since it would only be right at one vac setting. That screw on top is a physical stop for the regulating mechanism, boost can push it down more, but vac cant suck it up any more because the screw stops it.