What kind of Fuel Pressure Regulators are you guys using on your Turbo cars? Do you guys keep the stock one, use a Nismo one (not sure if there is even a difference between the 2), or go with an aftermarket one? I will also be using a 300ZX TT Fuel Pump, JWT Rail, and MSD 50lb injectors along with a JWT ECU if that makes a difference. Thanks.

You don't need a FPR unless you opt for the 4 bar program.

if you do go with the 4 bar

I would recomend the Aromovite FPR as the best
Value.

The AEM one is just as good but is more expensive.

Aeromotive or SX! You will only need one if you are runinng the 4 Bar fuel program!

why is a fuel pressure regulator needed for the 4 bar program only? Why would I want to run less than 4 bar with the 4 bar program, is the fpr there to be used as way to control a/f ratio ?

Excuse my ignorance,

:confused:

Factory fuel pressure is 3 bar (43.5 psi)! JWT's standard turbo program runs 3 bar fuel preessure *UNLESS* you pay a little extra for the hardware that Clark has to solder onto the ecu and an adjustable fuel pressure regulator! The 4 bar(58 psi) fuel program requires you to crank up the static fuel pressure via an adjustable fuel pressure regulator!

When i got my computer done by JWT about 2yrs ago . that is all they had was the 4 bar program i thought that was the standard then now i here they have a 3 bar program . what is the differance beside more fuel pressure ?? did they play with fuel and timing maps so they would not have to run the extra bar of fuel pressure?? why the change ? which is better ? does the 72lb hr program run on the 3or 4 bar program ?

4 bar give you more pressure and elevates the Duty cycle of the injectors.

50 lb msd's max hp about 340 with 3 bar & up to 425 with 4 bar.

4bar requires a daughter board and a Adjustable Fuel Pressure Regulator. To Control the 58 psi fuel pressure.

If you have the FPR and the 4 Bar there not much better.

I personaly went with the 3 bar as my goal was 300 whp.

Maybe one day I'll up it to 4 bar.

Yes, 72lb Injectors run on the 4 bar

Actually, the 72lb/hr injectors run on 3 bar, not 4 bar!

Well i got a sx Adjustable Fuel Pressure Regulator(got it for 50.00 from my friend) I have it set at 43 psi with a 3 bar program. Do I need JWT To reprogram my ECu for the Fuel Reg? Also are you sure the 50 lb msd's can only handle only 340 hp?

340 is pushing the limit of the stock fuel pressure with 50's
if you use 4 bar to up the pressure the 50's will flow more.
thus uping the potential to 425.

Hey Louis I thought with 72's you have to get the 4 bar because you max out the cobra maf and need the daughter board to flow more through it. Please explain?

I understood that Ben had 72's with the 3 bar but that was an experimental stage and now the 4 bar is standard for 72's.

The MAF and injector programs are independent of each other. The reson they seem like they go together is beause the upgrades are typically performed together. When people go to 4bar fuel with the 50lb injectors, they ususally get the MAF subtractor circuit at the same time to read more air so they can use that extra fuel. With the 72lb injectors, you can run 3bar fuel (stock, don't have to get a regulator or anything) and the cobra MAF with subtractor circuit. The subtractor circuit and 4bar program are two seperate things that do not necessarily have to go together. I think the only people running 72lb injectors are using the 3bar program. I know Aaron and Zak are. I'm not positive about Shaggy..? One thing to note: the72lb injector program is not perfect yet, and is still a developmental program. The 50lb program is much more refined and the 50lb injectors have a better idle. The 72lb program still has a little bit of development left to go. Aaron's car was running out of fuel at only 360hp on the dyno, despite the fact that the injectors will flow a lot more. They are still fine-tuning the maps.

andris

i hope a few of you guys can answer this question .

i have the 4 bar program with the cobra maf and 50lb-hr injectors
i went to the dyno and this is a pretty reputable dyno in my area
and they did the a/f ratio meter in the tailpipe . it was a digital readout and it graphed the a/f across the rpm range and it was a dynojet wideband a/f meter.
okay here is the problem

when i turned up the boost to 19 psi my car was running 10-10.5 on the graph , my EGT was reading around 840deg celcius.
now that is really rich !?
i actually dropped my fuel pressure down 5lbs to get the a/f ratio to come up to around 11
now i called JWT and they could not explain it i even talked to jim himself and he told that he was 99 percent sure the a/f ratio that i just and graphed was not accurate . what gives ??? i have seen 850hp supra tune there cars on this dyno and jim is telling me it is not accurate . if it is not accurate then why havent these guys blown there motors??
now i also called sr20 development and they told me the 4bar prog always runs richer ?????
is there more power there by playing with the fuel pressure < only on race gas now>

Originally posted by QuickZeek
340 is pushing the limit of the stock fuel pressure with 50's
if you use 4 bar to up the pressure the 50's will flow more.
thus uping the potential to 425.



So i just need to go to the 4 bar and keep the 50's injectors?

Does someone make an adjustable fuel pressure regulator that I can hook up to the GTi-R fuel rail... other then a NISMO? I would much rather use a aeromotive or sx or something... but this fuel rail has this stupid flange... and i really dont feel like having to cut a matching flange and weld a fitting on to it so i can use normal regulators...

-charles

Thanks Andris for Clearing that up.

We need an SR20 Turbo FAQ

It would be a good Idea to start a Sticky Tread for everyone who has questions like these that are asked over and over again.

Originally posted by andris
With the 72lb injectors, you can run 3bar fuel (stock, don't have to get a regulator or anything) and the cobra MAF with subtractor circuit. The subtractor circuit and 4bar program are two seperate things that do not necessarily have to go together. I think the only people running 72lb injectors are using the 3bar program. One thing to note: the72lb injector program is not perfect yet, and is still a developmental program. The 72lb program still has a little bit of development left to go.
andris

When I ordered my ECU from JWT, Ben told me that they don't have a 4 bar program for the 72# injectors.
So, they still have idling issues with the 72# injectors? I was hoping they would have worked these out since they worked with Shaggy's car so much. Also, Mike K said that they had fine tuned the 72# program as well. I guess I'll see when I finally get it all together.

BTW, So it looks like I have a Aeromotive FPR for sale.