Running higher Fuel Pressure than OEM Spec
 

Hello
I did a few search on the subject but couldn't find a definite answer.
Base on FSM, ~51psi is the OEM spec for fuel pressure at the rails.
Im going to be running around 58 psi from my current pump+filter setup to the fuel rail, would this cause any problems?
I know running the engine rich will shorten the life of Cat and emission component, but wouldn't the ECM compensate for the addition fuel from higher pressure?
Just trying to avoid adding FPR and fuel return system, since i have no plan for FI or making much more power in the future.
Any help is appreciated.

How do you plan to increase the fuel pressure?

I second this as well... how? is there a way without a FPR?

I'm actually not using the stock pump or stock gas tank. The 370z engine will be in a 240z swap. Hence I'm not looking for more power n try to keeping it simple with the returnless system.

Also another question, in stock 370z Effective pressure at injector change base on engine speed but rail pressure should be the same right?

It will probably be fine... I would recommend getting a wideband on it so that you can monitor it yourself and if its running too rich anywhere you can address it then. I dont know how far the stock ECU & stock calibration will go to try and correct it, never really played with it in that way. But 6psi extra pressure with stock injectors isnt going to throw you all that far out to begin with.

6psi isn't too bad, it's a bit high but not extreme. The ECM should probably be able to compensate that I would think. Probably not even throw a cel, I'm betting fuel trim will be around a -8 to -10 and not sure about Nissan specifically but usually cel won't hit till around +- 15. So ECM will know something is up but not enough to throw a code or actually even run rich.

To add to this though what may become a problem is what fuel volume the pump can send vs stock. Pressure and volume are two totally different things so if the old pump can't supply the volume then you will have fuel starvation regardless of pressure and if you have a monster pump with high psi and volumn then you may start running rich. Not sure the oem flow rate of either pump so may want to look into that before you get carried away.

FWIW, the European model 350Zs had an adjustment dial.

I shipped a lot of 350z fuel systems to Europe over the years... never heard anything of the sort! Do you have any photos or detailed evidence of this? I would love to check it out just for curiosity sake.

It's been a few years, but I remember popping the hood of a 350Z in a German dealership's showroom floor, and the owner, who was also a meister mechanic, pointed out an adjustment dial (possibly a screw) along the fuel system which was visible in the engine compartment but wasn't in my US-spec 350Z HR. It had a lime green cap and was on the left side of the motor. He said he could "adjust" my fuel pressure for free to achieve the 315 hp Euro-spec output. Never really put much thought into it until now.

I think he was pulling your leg.

Sounds like he was pointing at the EVAP test port.

To have adjustment in the engine bay would require the car to have a return fuel system.

To confirm, I just went to the German ebay site and looked at half a dozen 350z fuel pump modules and they are the same units we have here in the USA.

Thanks Phunk n Jhill, I figured that pressure should be OK but just wanna confirm with the 370z gurus.

Regarding the pump flow rate it should be around 190lph. I'm using a ls1 Camaro tank. I figure it good enough for v8 then our v6 should be no issue. Just the higher pressure output.

Any1 know what would flow rate on the stock z pump be?