Is it possible to run the 1995 FPR (Fuel Pressure Regulator) with the VQ35 Injectors and Fuel Rail? I assume it's at 3.0 bar like all the others so it should do the same job as the De-K or VQ35 FPR, right?

 

bump .

 

well i am running with a 96 fuel pump assembly and i have no problems at all.

 

What FPR are you running? (At the end of the fuel rail)

 

i never hooked up a frp to see but i am guessing that since i am using the 96 fuel pump assembly, same fp as a 4th gen max?

 

you don't have an fpr?

 

well i know that the 2k2 fpr is in the fuel pump assembly but where is it located on a 4th gen? i havea spare 2k2 fuel pump assembly that i am goign to put into my tank. i know that they idle at 51 psi.

 

I *think* the 1995 FPR, like the 2000-2001 FPR, is located at the end of the fuel rail. The pipe "passes through" the FPR and goes back to the fuel tank.

 

yes cause 4th gen and 5th gen have a return system and 5.5 gen have a returnless system. i am running a returnless system right now.

 

Here is what Nismo is doing (3.5 Rail with 2000-2001 FPR):



How do you run a returnless? You can't just seal off the end of the fuel rail, you need an FPR somewhere. Like you said 3.5 FPR is somewhere in the tank so I need another option.

 

and the whole reason is cause he is still going to use the return system? i dont see a problem for me because i have a complete swap with ecu so the ecu knows how much fuel is needed. plus i still have the dampners on the fuel rails.

 

i am using the 3.5 fuel rail and that whole system is returnless system so there is only 1 fuel line comming from the tank and it goes into the fuel rail. what i did with the other line that return to the tank on a 4th gen is i plugged it up so nothing would get into the line and into the tank.

 

I do not know if you are aware or not but the plastic tank baffle for the fuel pickup is completely different between 4th gen and 5.5 gen.

 

I don't understand how your car is running right without an FPR??

 

and why is that? i get no cel and i get 300-350 miles to a tank. and if the baffles inside the tank are different, i have a spare 5th gen tank in my garage so i will think of something. right now i am trying to get rid of my abs light.

 

It's running because the VQ35 ECU is programmed for 3.5bar and he's probably seeing just over 4bar or whatever the stock fuel pump SAFETY bypass opens at, which just means he's a bit rich during open-loop.

Running with the bypass open is not good for fuel pump life and fuel volume is going to vary, which is a concern if boosted but probably not for stock NA.

 

So I should be remotely okay w/ DE-K injectors, and FPR rite?

 

You'll be in the ballpark, I guess, but I would want to be able to adjust base fuel pressure up(get Walbro) or down and adjust AFC settings for fine tuning.

 

Why shouldn't he be able to tune his A/F?

Also will 1995 FPR work as good as the 2001 FPR on a return-style rail?

 

Other than closed loop (WOT), The ECU should be able to adjust the A/F by lengthening or shortening the injector pulse, right?

 

WOT is open loop....closed loop is where the ECU uses 02-sensor feedback.

Yes, during closed loop, ie warmed up and light throttle, the ECU will target stoich. However, that doesn't mean AFR won't be lean without a bigger injector or more fuel pressure to compensate for the 0.5L displacement bump.

 

lol, I knew I would get open and closed loop mixed up..:

 

I am planning on getting an SAFC-II to tune A/F. Will that solve the problem?

 

Different fuel setups guesstimate of supportable peak wheel horsepower....

Using 290cc DEK injectors and 3bar fuel pressure aka Nismo3112:
225whp@80%DC
281whp@100%DC

Using 270cc 5.5gen injectors and 3bar fuel pressure aka JClaw:
210whp@80%DC
262whp@100%DC

I'd have no problems pushing NA injectors to 90% DC, even a bit beyond. I think you guys will be fine with just an AFC for tuning open-loop.