Fuel Related Questions:

[chrismo240sx]

Whats up guys? Im in the process of dropping my gas tank to replace it with a used one froma junk yard. Im sending the tank off tomorow to get it hot tanked and cleaned. I was going to order a high flow walbro pump since im there doing it and i still have the 15 year old stock pump in there so might as well change it for 89 bucks shipped right? Anyways, here's my questions....

1) Will i notice any gains or improved gas mileage or anything from the pump?

2) If I decided to get an adjustable FPR, would it benefit me with an NA Ka motor?

3) If yes to Q #2, when do the stock injectors reach its limit, and will my car be running pig rich with the FPR?

To make things easier....i have a 93 240 with Ka24de with simple bolt-ons.

Intake, Header, Exhaust, High-flow Cat, Crank Pulley, JWT ECU, and E-Fan.

As always, thanks in advance,Chris

[hellzknight]

I dont believe youll see improved gas mileage.

Also youll need to run a FPR to bring it back to stock pressure or youll be running rich.

Correct me if im wrong.

[chrismo240sx]

really? the stock FPR won't do that, ECU too? Anyone else care to chime in

[liquid_cool]

im no expert..but....if your somwhat moded out..you might slightly benifit at the high end of your rpm range where most stock fuel pumps tend to not deliver whats needed and run the engine lean...thats why true race cars allways have larger fuel lines and a high flow fuel pump..its to eliminate starvation..running slightly rich wont hurt to much except in the wallet..but running lean..can couse system nightmares...and worst of all ..detonation falure..as in boom!..dead engine...with that said...stock ka24de sidefed injectors run at 9psi acording to my service manual....if you add a regulator..thats capable of going as low as 9psi..your in like flynn..there is another more expencive option thou....upgrading the fuel injectors them selves..and adding a regulator anyways...this unlocks a lot of potential for a turbo build into the upper psi ranges and horsepower ranges..but this is not cheep...take a look in my myspace pics..i just ran a high output fuel line that cost me well over $700 in line and fittings to date..not including the pump..hope this helps.

[carmo]

It all depends on which fuel pump you get. A walboro 255 will laugh at your factory FPR. I'd suggest the pump and an aftermarket FPR and then set the fuel pressure slightly higher than factory. Maybe around 50psi at idle. Oh, yea you also need to figure out a way to put a little fuel pressure gauge on the supply line to the rail. With the intake and full exhaust plus the JWT ECU this fuel upgrade should free up a few extra ponies. I suggest your next mod be a wide band air fuel ratio gauge and a retune on the ECU. This way you know your getting everything out of what you paid for so far.

[chrismo240sx]

wow thank you guys so much, the last 2 posts were great. I dont know about upgrading the injectors, but i think before i install the walbro 255, ill get a FPR too.

About the 50psi, whats stock psi levels at idle? Turbo might be in the distant future but for now im sticking with the bolt-ons, its cheap enough and fast enough for a 4 banger to break the @$$ end out!!! and not to mention a fun daily driver

[chrismo240sx]

oh yea, and i definately want to retune the ECU....one to get a few extra ponies and 2) to make sure the air/fuel levels are good and to improve the gas mileage.

what would be best for this?..... SAFC and a dyno?

[carmo]

talk to some of the guys at your local tuning shops, there might be a cheaper way. My accord is bored .20 over with port and polish, racing pistons, rods, and cam shaft and the tune only cost me $270. So that was an Integra LS computer chipped with Chrome and enough pulls on the dyno to get the thing to run right. I think the SAFC is double that alone. See if there's a company like Hondata but for Nissans. Once you chip the control unit, anything you do to the car after that is just a couple quick pulls on the dyno to tune it up.

And I'm not sure but I think factory fuel pressure is around 45 psi at idle.