So of course it's better to have a return system, but exactly how many are running w/o one. Any problems? I understand that fuel pressure at idle will be high, but what's the real negative impact of it?

 

i would get aam basic fuel return if u dont want to spend alot of money....when i procharged - after 7psi the fuel pressure was all over the place and was real hard to tune...helps cause u can add one psi per psi of boost...so i would negative effect...harder to tune and then u wont get all ur hp u want out of it because it would have to be a "safer" tune
http://www.alteredatmosphere.com/mm5...y_Code=350Z_FS

 

I have 650cc injectors, and no fuel return. Everything is fine, no problems.

I hope this helps:

https://my350z.com/forum/showthread....rmance+Factory

 

I have 550cc injectors and no return system. No problems at all.

A good tuner will tell you what needs to be done. Some cases you can get by, others you can not. All depends on several factors.

 

+1

 

i have 20 cars running around with that same setup, mostly all stock motors...


we are about to push AJs car a little bit to see how the stock system holds up.

 

No return on my ride either.479WHP on stock motor and no problems for 28,000 twin-turboed miles

 

Should I just drop the Walbro in, or do I have to mod it?

 

are you F/I??

 

I have Vortech w/ newly installed 3.12 pulley, 440 injectors...fuel pump going in this week along w/ test pipes. Hope to get it tuned by this Saturday.

 

I would definatly get it tuned when you put it in

 

Yeah ever since putting in the 440's its been running super rich.

 

I have 440 + Walbro , no return and about 80psi fuel pressure at idle and slightly lower at driving .. At WOT the FMU and Aux fuel pump kick in and fuel pressure rises to around 95/100 psi.. Its tuned and runs well..

I would look into the Walbro mod's Tn recommends as well as Phunks mod to the swirl jet to bring the Fuel press down to around 50psi idle..Not sure what long term ill affects running a high fuel pressure might be...

 

One reason not to run real high fuel pressure with a walbro is flow. The flow falls off drastically with high fp.
Approximate flow from Walbro 255:
@50psi supports ~650bhp
@70psi ~588bhp
@90psi ~444bhp
@100psi ~325bhp
@110psi ~156bhp

 

With my Stillen kit, I was running a Walbro 255 and just the regular RC750 7th injector. With the Vortech, I'm running the 3.12 pulley, Walbro 255, and RC 440's. I'll let you know how it goes when I get down to fine tuning it...

 

I have been running a walbro pump w/o a return line on a stock motor for a year now with no problems. I believe I am a bit rich but nothing to drastic.

 

So you're running a Walbro 255 along with the Vortech FMU and auxiliary 155lph fuel pump?

 

Yes.. and RC 440 cc inj's..

 

I have the walbro 255 and no return fuel system.. Fixing to add some injectors.

JPC no need to run that aux. pump with the vortech if you are running the 440's, walbro and fmu.

 

I am sure you are correct but I have it tuned with this set up and would have to get it retuned w/o the FMU/Aux fuel pump....No return system. How is your A/F ? A dyno chart would be great..Do you have a fuel pressure gauge and what pressure do you see at idle and WOT?

Thanks