255 lph fuel pump question

[river]

my buddy is installing a 255lph high flow fuel pump into an otherwise stock fuel system in a 1G AWD. he does not have an safc, injectors, or a fuel pressure regulator. my question is, after hearing many different things, will he need a fuel pressure regulator or anything else to control fuel flow to the injectors? ive heard also that a high flow fuel pump on a stock system without a fpr will possibly flood the injectors. does anybody have any info on this? will it be okay to install the pump, and the pump only? will there be any problems? he is planning on taking the smaller screen out of his MAS to get away from fuel cut also. will this work? ive never done just a half install on any car ive worked on, so i dont know how putting in just a 255lph high pressure pump and hacking the MAS will effect the car. please help me out before i make a possibly stupid move helping him do this.

 

[ho bag]

well i added the 255 low preasure unit and it does over run my fuel system on the low end and idle. its very hard to tune the car and in your case you cant tune it at all. i suggest spending the money on some tuning devices first unless your fuel pump is dieing liek mine was

 

[ECLIPSE4x4]

I would not reccomned it without and S-AFC or and adjustable FPR like aeromotive.

 

[skoolz4loserz69]

i've got a 98 rs eclipse and installed the 255 walbro fuel pump and my car does seem to be slower. i do have the safc2 but put all of the settings on ZERO due to not enough knowledge on how to tune it correctly. could i get it dyno tuned to where the fuel pump actually comes to my advantage and gives me more hp?

 

[onegee]

Correct me if Im wrong, but I dont really see the need for a fuel pump upgrade on a NT unless you're running some kind of aftermarket force induction. You're more than likely running PIG rich hindering your car's power.

A fuel pump alone does not give you more horsepower. Turbo DSM's run a bigger fuel pump to run more boost, in conjunction with a properly adjusted base fuel pressure. As the boost goes up (air flow), the fuel needs to keep up as well. I've haven't really done alot of research or read much about NT cars upgrading fuel pumps unless they were moving a dramatic increase of air above stock levels.

 

[ACKERSON]

All very good points but don't forget to rewire the pump, there is a huge gain from a simple rewiring job. I measured less than 9 volts at idle on my car then rewired and measured 13 volts.

 

[guitarXgeek]

All very good points but don't forget to rewire the pump, there is a huge gain from a simple rewiring job. I measured less than 9 volts at idle on my car then rewired and measured 13 volts.

Word. I was getting around 16+ counts of knock from the middle to top of 3rd before I did my rewire. With the exact same tune settings and the same (relatively) ambient temps, the knock dropped to 3-5 counts after the rewire! Maybe something was wrong with my stock wires (besides them being too damn small), but it was a HUGE improvement. If that's not proof enough for you, then I don't what is

 

[skoolz4loserz69]

well i was in the middle of putting a turbo kit on my n/t until i noticed that the turbo was shot, so that's why i have the 255 fuel pump installed on my car. However; i figured since the computer regulates the fuel itself anyway and the pressure should always be the same, bigger fuel pump or smaller one, it shouldn't really matter what size it is. Is that correct?

 

[onegee]

well i was in the middle of putting a turbo kit on my n/t until i noticed that the turbo was shot, so that's why i have the 255 fuel pump installed on my car. However; i figured since the computer regulates the fuel itself anyway and the pressure should always be the same, bigger fuel pump or smaller one, it shouldn't really matter what size it is. Is that correct?

Incorrect. A fuel pump the size of a 255LPH is known to overrun the stock fuel pressure regulator. As far as turbo dsms go, installation of a higher flowing pump above the 190 (and some say even this pump overruns stock FPR) calls for an adjustable fuel pressure regulator.

AFAIK the ECU does very little regulation of fuel as far as the fuel pressure goes, its more the job of the fuel pressure regulator on the end of the fuel rail.

Hope you get it all sorted out.

pz

 

[skoolz4loserz69]

Incorrect. A fuel pump the size of a 255LPH is known to overrun the stock fuel pressure regulator. As far as turbo dsms go, installation of a higher flowing pump above the 190 (and some say even this pump overruns stock FPR) calls for an adjustable fuel pressure regulator.

AFAIK the ECU does very little regulation of fuel as far as the fuel pressure goes, its more the job of the fuel pressure regulator on the end of the fuel rail.

Hope you get it all sorted out.

pz

Alright i appreciate the help man. I'ma put in my oem fuel pump and see if that really solves the problem. I'll post the results. Thanx

 

[skoolz4loserz69]

so i took the walbro out, put the stock one back in and it feels so much better. thanx guys

 

[onegee]

Glad to hear it worked out.

 

[THE_ARTIST_]

i would get at least a S-AFC and a logger before you put in a 255. i had them in before i put in my 255 and i had to lean out the fuel trims to get it running properly.