THE TECH

iTrader: (154)

I have been searching around about this. I have read several posts about how when people put a Walbro in, the fuel pressure wasn't stable. I'm wondering why this is. Has anyone come to some sort of conclusion on that? I've put Walbros in several other cars and you don't need to add an aftermarket FPR for everything to work right. Does it have something to do with the returnless fuel system the Z has? I'd like to just drop a Walbro in for the added safety but don't necessarily want to have to add an FPR to the car as well.

jpc350z

I added a walbro and 440inj's.. My fuel press is up to 80 psi.. Reason I believe its that high is the OEM press reg can't reduce it due to the higher flow rate out of the walbro...A return system would resolve it and bring it down to low 50's...Only problem with 80 is you don't have good low engine load control...somewhat jerky/not smooth at low rpm's particularly in stop/go traffic..

THE TECH

iTrader: (154)

So then all you really need is an adjustable FPR right? Can you fit 440s in the stock rail? You are using the flash to control the injectors then I assume from your mod list?

jpc350z

If you go with a fuel return I believe an 1:1 fuel regulator is included.. The stock rails are compatible with RC440's and I had the car dyno tuned to control the inj's for a A/F ratio around 11.5..

THE TECH

iTrader: (154)

So you're not using anything to counteract the high fuel pressure? I believe that AAM sells an FPR fitting that will replace the stock regulator that will allow the use of an aftermarket FPR. I believe that this would remedy and sort of fuel pressure issue.

jpc350z

AAM did the work and assured me running this high a pressure is not a problem..However it scares me when I see the pressure on the fuel gauge..I'll have to enquire about there fitting and aftermarket FPR...Thanks

phunk

iTrader: (21)

take out the fuel pump assembly.

using a downward force carefully pry the little yellow plastic part off the bottom of the fuel pump assembly canister. it will snap out.

using a .070" drill bit, increase the inside diameter of just the tiny little pinhole. reassemble everything.

this should solve your problem.

THE TECH

iTrader: (154)

Does this mod somehow allow the stock FPR to work correctly?

phunk

iTrader: (21)

it might

THE TECH

iTrader: (154)

I'm confused. How do you endorse a mod that "might" fix the problem? I'm not bashing, just asking.

phunk

iTrader: (21)

because i dont know if it will do the trick or not. so it might work, but it might not. if the regulator itself is the return flow restriction then it will not work or it will not work 100%. however, what i am telling you to drill out is a known restriction that needs to be addressed when a walbro 255 is used but the stock regulator isnt even there. ive never tried it while keeping the stock regulator in place.

but i can tell you that even if the regulator was not a problem, what i am instructing you to do is a problem. so fix the known problem, and if it doesnt get you all the way there, then look at the regulator itself or send it to me and i will modify it for you.