# aeromotive rrfpr instead of a fmu?



## EvilVento2.oT (Dec 1, 2003)

as it states set up is as folows aba obd2 custom chip g60 injectors and vortech "blue" fmu running 8-11 lbs 8.1/1 comp(2 hg's) {soon} want to run 12-15 but i need the fuel so i was thinking about this unit


----------



## EvilVento2.oT (Dec 1, 2003)

*Re: aeromotive rrfpr instead of a fmu? (EvilVento2.oT)*

ttt


----------



## MDTurborocco (Aug 24, 2003)

*Re: aeromotive rrfpr instead of a fmu? (EvilVento2.oT)*

Can you please explain what the Vortech unit does? I thought it was a RRFPR. I have read once that a 4bar FPR and G60s would give just enough fuel for 1 bar of boost. Thats really pushing those injectors but the guy says it was doable. Also that would leave you with a terribly rich low end. Im just throwing things out to bump this up cause I am also interested.


----------



## 1.9..16vTurbo (Jan 25, 2004)

*Re: aeromotive rrfpr instead of a fmu? (MDTurborocco)*

here's another bump b/c i too have yet to decide what to use and would like more info.


----------



## speed51133! (Aug 5, 2002)

*Re: aeromotive rrfpr instead of a fmu? (1.9..16vTurbo)*

not to be...mean....but
learn what a fuel pressure regulator does, and how it works.
your stock regulator is a rising rate regulator, as is a vortec, as is the aeromotive.
an FMU refers to a rising rate regulator that has a rate of above 1:1, like 2:1, 3:1, 4:1 etc.
your stock regulator and the aeromotive in the pic is only a 1:1.


----------



## MDTurborocco (Aug 24, 2003)

*Re: aeromotive rrfpr instead of a fmu? (speed51133!)*

Alright well tell me if im correct here than. Even if you got a aeromotive or whatever adjustable FPR mounted on the return line of the fuel rail the lowest pressure you could run would be what the stock FPR is set to (3 or 4 bar). The best thing I found was a drop in fuel rail adjustable FPR from ecstuning but it was 200$ a little high if you ask me. Is this a correct statement? 
Also when I took off my vacuum to my stock FPR Fuel pressure rose to 45 from 40. Does this mean when vacuum is hooked up fuel pressure is 40 until WOT than it goes to 45. I know im slightly wrong there. Thanks for any that will spread some knowledge, im still a newb i guess lol.



_Modified by MDTurborocco at 7:13 AM 1-26-2004_


----------



## SavageRocco (Apr 23, 2003)

*Re: aeromotive rrfpr instead of a fmu? (MDTurborocco)*

I am running the Aeromotive FPR along with a Cartech RRFPR after it. That gives me more option for tuning high end and controlling additional fuel under boost with out having to change the chip everytime. Takes more time to dail it in, but is more adjustable. That way I can run lower initial base fuel pressure for a smother idle and use the RRFPR to bring fuel on as I need it. I just started to get mine running better when I lost my 6th trans. I just pulled it tonight and will get my new trans with the Quaife installed tomorrow I hope. I have some pics on my website of the FPR RRFPR setup










_Modified by SavageRocco at 12:40 AM 1-26-2004_


----------



## speed51133! (Aug 5, 2002)

*Re: aeromotive rrfpr instead of a fmu? (SavageRocco)*

with the exception of some craze new stuff on the market like EFI with no return line.....
any fuel injected regulator will be rising rate. but the rate is 1:1. if it has a vacuume nipple on it, its a rising rate. this means if you boost 5psi with a turbo, and you set your fuel pressure to 55psi, you will maintain that 55psi. if you did not hook up the vacuume nipple, when you boost 5psi, your fuel pressure would fall by that 5psi. The turbo compresses air against the entire poost pipe/intake manifold. that air pressure is pushing against the pintle of the fuel injector. so the fuel has to overcome that 5psi just to get into the manifold, where normally it doesnt have any pressure, it has a vacuume pulling it in.
Understand?
ok, so now you got that, some regulators have a rising rate of MORE than 1:1. lets say you go with 8:1 as your rising rate. that means for every 1psi of boost, your fuel pressure will rise 8psi. so if you run 5psi, your fuel pressure is now 8x5=40psi on top of your base pressure.
So your stock fuel pressure regulator is say 60psi, you run your car at 5psi of boost, and have a cartech regulator set to 8:1. when your in full boost your actually running about 60+5+40=105psi of fuel pressure.
I may be a bit off here, as im not sure how accurate the regulatos are, but thats the basic idea of how it all works. Buying an aeromotive regulator like the one above, and slapping it on your stock rail, that already has the stock regulator, will accomplish absolutley NOTHING. both are just 1:1 regulators. It would allow you to adjust your base pressure, but thats it. if that what you want to do, id say buy a billet rail, and mount just 1 regulator like the aeromotive. i make rails


_Modified by speed51133! at 7:16 AM 1-26-2004_


----------



## pqgti (Oct 27, 2003)

*Re: aeromotive rrfpr instead of a fmu? (speed51133!)*

good info








but 8 times 5 is 40


----------



## speed51133! (Aug 5, 2002)

*Re: aeromotive rrfpr instead of a fmu? (pqgti)*

edited, hahahah


----------



## EvilVento2.oT (Dec 1, 2003)

*Re: aeromotive rrfpr instead of a fmu? (speed51133!)*

great info!! gonne switch to a 4 bar reg. anf see what happens !!! learned alot from this!!


----------



## Jefnes3 (Aug 17, 2001)

*Re: aeromotive rrfpr instead of a fmu? (speed51133!)*


_Quote, originally posted by *speed51133!* »_with the exception of some craze new stuff on the market like EFI with no return line.....


speed: The regluator is in the tank, its part of the module. Cost saving measure 
for OEMs... one less fuel line per car.
(I used to design In-tank modules for 'Walbro') 
Pain for NA/FI conversions since the rail pressure is now 'fixed', 
no manifold pressure reference on the backside... http://****************.com/smile/emthdown.gif 
Jeffrey Atwood


_Modified by Jefnes3 at 5:41 PM 1-26-2004_


----------



## speed51133! (Aug 5, 2002)

*Re: aeromotive rrfpr instead of a fmu? (Jefnes3)*

cool, i thought it was regulated by the pump rpm.


----------



## Marty (Jul 14, 2000)

*Re: aeromotive rrfpr instead of a fmu? (Jefnes3)*


_Quote, originally posted by *Jefnes3* »_
speed: The regluator is in the tank, its part of the module. Cost saving measure 
for OEMs... one less fuel line per car.
(I used to design In-tank modules for 'Walbro') 
Pain for NA/FI conversions since the rail pressure is now 'fixed', 
no manifold pressure reference on the backside... http://****************.com/smile/emthdown.gif 
Jeffrey Atwood

_Modified by Jefnes3 at 5:41 PM 1-26-2004_

I believe they put the FPR in the fuel filter module on the new Audis.


----------



## SavageRocco (Apr 23, 2003)

*Re: aeromotive rrfpr instead of a fmu? (Marty)*

Actually, yes there is a bypass style regulator in the tank right off of the fuel pump on the new returnless style setups, but they are also trying to keep from heating up the fuel as it runs constantly through the hot fuel rail in the engine compartment. That reduces evaporative emissions. Ever seen the seen the squiggily air coming out you tank on a hot day when you open it? Yes the EPA monitors that too. As a bonus, fuel filters are now lifetime parts since they only filter the gas one time instead of endlessly.
But back to the controlling fuel pressure. Mostly on fords, but becoming more comon is a variable voltage to the pumps to decrease load and heat. There is a rail pressure sensor mounted where the regulator used to be and the computer controlls the pump via a duty cycle signal. There have been system aftermarket that boosted voltage to the fuel pumps. Whipple supercharger kits came with a device like that. Under boost, there was a solenoid that restricted the retunr line and raised fule pressure and the boost-a-pump increased voltage with transformers by 4-6 volts. Kind of an odd system. Solved a problem of raising fuel volume when you have a sucky in tink system.


----------

