Freemananana

iTrader: (3)

The question of whether or not you can run a Walbro 255lp in tank fuel pump with stock injectors and a stock FPR has been asked many times, both sides chime in equally.

My question is whether or not running a stock FPR with a Walbro 255 lp fuel pump, RC 750 cc injectors is okay if the motor is tuned. Will the fuel pressure possibly be higher? It shouldn't have any real effect since it is tuned on whatever the fuel pressure is, shouldn't it? I'm just wondering if I need to add an adjustable fuel pressure regulator on my stock B16A fuel rail or not. Or do I need to upgrade my return line? I just don't want to run into any unforseen issues. It's a very mellow set up, mostly stock, 250whp.

Car is tuned on Neptune Demon RTP. I don't think anything else should matter when speaking about the fuel system. But if I am missing something, let me know.

Thanks

turbohatch96y7

iTrader: (15)

You only need an adjustable regulator if you need to bump up the base fuel pressure to make more power.

Your already overkilling with 250whp and 750cc injectors.

Its fine as is. Leave it alone.

Freemananana

iTrader: (3)

If the walbro ups the fuel pressure, I won't run into any issues will I? I know the 750s are overkill...but I got a deal on em.

turbohatch96y7

iTrader: (15)

No it should stay at the stock pressure.

Plenty of people run a walbro with a stock fpr. I did. For a while.

Put a gauge on your feed line to make sure.

Charlie Moua

iTrader: (3)

fuel pressure may go up slightly, but nothing to worry about.
i kept my fpr stock with my walbro 255


when i installed the 400, fuel pressure went up to 60psi at idle.
I did not want to gamble on how long i could keep using a stock fpr so i got aem and turned it down to 45psi.

Freemananana

iTrader: (3)

Alright. Sounds good. 255lp is more than enough even for my extended plans.

Turbo-LS

iTrader: (4)

Stock regulator good for I believe up to the 400hp range in commonly used turbos in basic setups after that you Need an adjustable regulator

$MIKE$

iTrader: (13)

Should be good with oem I had a oem h22 fpr on my set up made 550

Tony the Tiger

The stock FPR diaphragm will tend to stretch over time under higher boost... If you are running above 14-15 PSI, it is better to upgrade it if the car sees frequent boosting. Smaller turbo guys with high boost levels are more prone to having this issue.

It also has trouble maintaining past 60 PSI of overall rail pressure; so if you are running 45 PSI base + 15 PSI of boost, any further boost will force you to compensate with more injector duty cycle and spray quality will go downhill from there.

Freemananana

iTrader: (3)

I'm running stock plus 10 PSI from the compressor housing, so it's probably more like ~8 at the throttle body.

As far as frequent boost, it sees it daily. But not for long periods or high PSI. I think I will get an adjustable FPR, but it's nice to know it isn't a current weak point. I'll keep an eye out for one.

What does everyone suggest for a adjustable FPR? I am sure I can find out by searching. Is it better to have a guage mounted on the fuel filter and the FPR in stock location? Or an all in one unit mounted in stock-ish location?

Axatax

There's no problem with this on these cars fuel systems.

My build was gradual, and I ran the Walboro 255 FP for probably around 1 year on a bone-stock Y7 2K DX before going with larger injectors and EMS.

Freemananana

iTrader: (3)

Preaching to the choir. My build has been gradual too. I guess I shouldn't have an issue with the fuel pressure for now at least.

Garrett

when I check all Honda that I tuned with boost on stock FPR, over the years I think that less than 20% were 1:1 fuel rising rate on boost.

since several years all Forced induction that I tune have aftermarket fuel pressure regulator