First off, I'm going to give some general info on fuel pressure regulators. Then I'll give a step-by-step on how to set the fuel pressure. If this sounds weird it's because I'm copying and pasting from an email I just wrote.

Althought just about any FPR can be made to work the SR NISMO one is the easiest. The PN is; 22670-RR580 and looks like this;

You will have to use a longer peice of hose as the angle on the outlet is wrong and you will have to loop it around to make it work. Many of us have been running them like this for years with out a problem.

In answer to your questions, no, the stock FPR isn't a rising rate, and you don't want a rising rate. They use rising rate FPR's on NA cars that have been converted to forced induction (turbo/supercharger). Since our ECU already has all of the info it needs to add the correct amount of fuel based on the input it's receiving from it's various sensors, all you need to do is give the fuel injectors 36psi static pressure and everything should be OK. If you use a rising rate FPR, your AFR's will get horribly rich as boost pressure increases. As for the 90° hardline, yea, you can remove it.

Static fuel pressure is the fuel pressure that is in the rail relative to the vac/pressure in the manifold. The purpose of a fuel pressure regulator is to give the injectors a relatively constant amount of fuel pressure so that the ECU is easier to program. Here is what I mean; under vacuum, with out a fuel pressure regulator, MORE fuel would be injected than normal since the manifold is "sucking" the fuel into the rail. To compensate for this, the FPR drops the pressure in the rail so that not as much fuel is available to be injectors. The opposite happens under boost. The pressure in the manifold pushes back on the fuel trying to come out of the injectors. With out a fuel pressure regulator, you would have to keep the injectors open longer, or use bigger injectors, which can make having a smooth idle difficult. With the FPR installed, when the boost pressure in the manifold increases the regulator increases the pressure in the fuel rail in a linear proportion so that the same relative amount of fuel is injected. AKA, with vac fuel pressure goes down, with boost, fuel pressure goes up.

It is nearly impossible to set static fuel pressure with the motor running, so don't bother trying. Here is how I do it;

Install new fuel pump

Install fuel pressure regulator

Install fuel pressure gage. It needs to come after the fuel filter, but before the fuel pressure regulator. Right after the fuel filter is the easiest.

Remove cover over fuse/relay behind the battery

Find the fuel pump relay. On my car it's green. Look at the diagram on the top of the cover to determine which relay is the correct one

There are two tabs holding it in. Depress the tabs and pull up on the relay. It should come out

You will now see 4 female spade connectors. 2 are close together and 2 are farther apart. It looks kinda like this;

Build a jumper wire. This is simply a short piece of wire with both ends stripped. Make sure it is of a decent gauge as the fuel pump pulls a moderate amount of amps

Insert the jumper wire into the 2 spade connectors close to each other

Turn on the ignition. DON'T START THE CAR! The fuel pump should come on and stay on

Using the adjustment on the fuel pressure regulator, set the fuel pressure to 36psi via the needle on your fuel pressure gauge

Turn off the ignition, remove jumper, reinstall the relay and cover, and start the car.

The fuel pressure at idle should be LESS than 36psi. When you are in boost it will be MORE than 36psi. If you've installed the gauge under the hood like I have, you won't be able to read it, but that's not a big deal as long as you've got a Lambda/AFR gauge.

Enjoy your properly fueled car!

Quote, originally posted by themadscientist »

Ask for directions to soapland, bring about Y50000 and don't take your mom.

I don't mean to nit-pick, but I believe that the Nismo Adjustable FPR Type-A is rising rate, 1:1 to be exact. That is the reason that there is a vacuum hose fitting on the regulator.

EDIT: Replying to a 3 year old post, noob is me.

Does that make more sense?

Ryan, this may help people too. This is how to properly install an adjustable fuel pressure regulator.

Edit: NVM found it... http://www.driftopia.com/2007/...r-fpr/

or a link to thread...i thoguht i saw one long ago...but that comp died... -_-;

tip : Fuel pressure hose is 5/16'' incase anyone needed to know...i did...lol

Modified by DALAZ_68 at 9:33 AM 12/28/2009

SoOn tO cOmE : honestly, i just dont know anymore

Modification list:
Walbro 255lph, Nismo FPR, CXRacing full 3" exhaust and manifold, FMIC, and radiator, electric fan, intake, Autometer Phantom Boost, Oil Temp/Press, Water Temp, AutoGage Fuel Pressure gauge, HKS Turbo Timer, Greddy Oil Adatper w/ Thermostat, HKS EVC-S EBC, VLSD, Top Fuel & Godspeed Oil Catch Cans, DIY Cooling Panel, KA Throttle Body, B&M Oil Cooler, ARP Head Studs

but i need some info on how to actually physically remove it... what are the easiest access point, over the manifold, under the manifold?

do i have to remove the manifold itself?

i pretty much need a walk on it, but my searching skills on this topic suck... :-(

and im running on 2 hours sleep for the last 2 days...

then remove the IACV, then the whole fuel rail and change it out that way. its the easiest way i've found.

is exactly what i will do...im assuming i should change out the O-rings while im at it...?

Definitely do this, such a smart thing to do while your in there. I hate injector o-rings.

Quote, originally posted by MeanGreenS13 »

A FIRE.

err,,,kinda how i lost the SOHC...

When injectors are tested they run ex. precision 43.5 or 50 psi not closed but open it has 50 psi when closed it probably spikes to 58psi closed at 1000cc's. This is what i was told.

but, then again you can't always believe what you hear.

Modified by warren540 at 2:32 PM 3/5/2010