Do I *need* a fuel pressure regulator?

Ghettoraid · 12-02-2002, 12:08 AM

Sorry in advance for my newbness.. but I was recently told by.. ehh.. cant remember he's a regular here, sold me some injectors.. heh that in order to run the boost I'm looking for, and to run these larger injectors I will want/need a fuel pressure regulator.

What I'm wondering is... how did my car get by BEFORE all the new mods? Prior to the last few weeks, before I set out to rebuild it all, it had JE Pistons, ran 6 lbs on low, 9 lbs on high. Same turbo, same fuel pump. Ran fine, no problems... not a FPR in sight...

But now, with my aspirations to run 15 on low, 18-20 on high.. with new injectors I'm going to need a new FPR?

I believe there is something back underneath car very near fuel tank that looks like a regulator, its anodized blue...I described it to the guy I mentioned earlier, he said it probably came with the kit (didnt really come in a kit but ohtay) and was most likely 12:1.

Thanks!!

I'll try to get a picture of the blue reg i mentioned if it'd help.. doesnt have a gauge on it or nething.

Also... which FPR's, specifically, would anyone reccommend? (assuming I need to buy one)

larryd · 12-02-2002, 12:41 AM

wether or not you need a fuel pressure regulator depends on your fuel pump, not the injectors or the amount of boost you intend on running.

insane147 · 12-02-2002, 12:43 AM

not only that, your running more boost now and the stocker NA one dont cut it. you need a rising rate fpr on her.

larryd · 12-02-2002, 12:46 AM

not necesarily.. you can run alot of boost on a T25 and be fine on the stock FPR becuz odds are your still on a stock fuel pump as well.. Ofcourse if you put a big fuel pump in then you need the FPR to be able to adjust the rate.

Formz · 12-02-2002, 09:45 AM

Quote:

Originally posted by Ghettoraid's sig
HKS/Turbonetics T04R Turbocharger.....ACD 500cc Injectors

TO4R and 500cc injectors? That can't be a good combo.

Ghettoraid · 12-02-2002, 10:23 AM

Quote:

Originally posted by Formz

TO4R and 500cc injectors? That can't be a good combo.

550cc.. just put 500 in when I thought thats what I was buying.. heh..

It's a supra T78 fuel pump (maybe from the GReddy kit??). Dunno if it's sufficient...

insane147 · 12-02-2002, 10:37 AM

"not necesarily.. you can run alot of boost on a T25 and be fine on the stock FPR becuz odds are your still on a stock fuel pump as well.. Ofcourse if you put a big fuel pump in then you need the FPR to be able to adjust the rate"

he has a eclipse rs which i would assume does not come with a boost friendly fpr since it has the neon motor.

Ghettoraid · 12-02-2002, 10:41 AM

Quote:

Originally posted by insane147
"not necesarily.. you can run alot of boost on a T25 and be fine on the stock FPR becuz odds are your still on a stock fuel pump as well.. Ofcourse if you put a big fuel pump in then you need the FPR to be able to adjust the rate"

he has a eclipse rs which i would assume does not come with a boost friendly fpr since it has the neon motor.

is anyone reading about the "blue anno'ed" thing that I believe is a FPR near my fuel tank?

At idle there's a good deal of unexplained noise back there.. and I'm guessing mitsu wouldn't want a noisy fuel pump.. ya know?? So I'm inclined to believe that it is an aftermarket fuel pump making all the noise..

Ghettoraid · 12-02-2002, 08:51 PM

But.... if I leave the OE injectors, don't turn up boost any more, I won't need one right??

talonted_one · 12-02-2002, 09:44 PM

I don't even see where the debate about this is.

YES you need an AFPR. I thought that was a given.

IMHO if i were you since you seem to be serious about this, i would do the entire fuel system.

talonted_one · 12-02-2002, 09:49 PM

Quote:

Originally posted by Formz

TO4R and 500cc injectors? That can't be a good combo.

oh and i share in Formz concerns. 550 cc sounds very skimpy for a TO4R.

Ghettoraid · 12-02-2002, 10:02 PM

It.... ran.... fine... in fact it was too RICH if anything.. hell.. I was spraying gas out of my exhaust... using STOCK INJECTORS...

=-\

I'm not looking for a debate. I'm asking:
1.) Will I need one to run more than 6/9psi
2.) Will I need one just to run 6/9psi? (it didn't before the new, lower compression pistons)

Ghettoraid · 12-02-2002, 10:10 PM

ppl know this is a 420a, right??

i had this in 2.0 turbo forum orginially... :roll:

DrZiplok · 12-03-2002, 11:56 PM

You may need a new fuel pressure regulator for one of two sensible reasons:

- You want to run a base fuel pressure other than the default.
- Your pump outflows the stock regulator's ability to bypass.

Conventional wisdom for the 4G63 DSMs is that if you go over 200lph in pump capacity, you will want a new FPR due to the stock regulator having an undersized return orifice.

I don't know anything about the 420a's FPR. You should get a fuel pressure gauge and measure it yourself, or go attack a Neon forum to find out at what point they tend to switch over, since you're going to find more people there that know what's going on.

btw, your setup is pretty impressive; nice to see someone doing something other than desk racing with a 420a DSM.

talonted_one · 12-04-2002, 12:05 AM

im not sure if the 420a's regulator can handle 6lbs of positive manifold pressure. the car is nautrally aspirated stock so why would it have to.

every turbo and supercharger kit will normally include a fuel pump, AFPR and maybe even injectors.

You are bolting on a pretty big turbo with a pretty big fuel pump and pretty big injectors. why not give yourself the extra security and maybe even better performance by getting the regulator?