[MaxHax]

If the Walbro only flows about 20 or so more than stock and is the exact size as stock why would you need an FPR and vaccum line inside your car up to the engine bay on our returnless fuel system?

Wouldn't it just dump any extra back into the tank?

If you are just barely lean and want to add a little more fuel at what point do you need to go return line and why?

Max

 

[toykilla]

wow that is jumping into some deep waters right away!

i am a newbie at engine mods but i am learning every day and later this year i hope to be doing some FI on mine.

your experience is welcomed here max

 

[MaxHax]

Thanks for having me.

I guess I should start off by saying I have a scer with 9 pounds of boost and retarded the timing and all of the other safety buffers people reccomend.

What I found was when you gewt a larger fuel pump on a returnless fuel system like our beloved Z and you add too much fuel like say a 280L SARD you will have extra fuel.

The returnless system doesn't know how to regulate it so you can buy an FPR
Fuel Pressure Regulator.

My findings from 2 sources show that the stock pump flows like a mofo!

It's a tiny little thing (picture a can of Red Bull.) It is about that size exactly so it's moving some fuel!

The replacemnt that drops right into it's spot is a Walbro 155 and is the exact same size, even the same color!

It flows more but not obscene amounts more. I was in LA and saw 5 fuel pumps laid out. SDome were obscene when you see how dinky the stock and Walbro are.

Like picture a Monster Energy DRink can or .5 Farad Audio Capicitor as a visual guide.

The regulator and line is almost 300 more and I am trying to see if I can just drop the Walbro in there without an FPR and a line run through my car (tearing apart the inside of my car for like the 5th time.)

So I guess that will help make it make sense.

If the Walbro just adds enough to keep you inline with a 11-12 A/F ratio (what my ECU has been reflashed to run) would the FPR still be necassary?

Just thought I would throw this out for discussion, meanwhile I am waiting to get paid before I decide so if I find out more I will keep the thread alive.

 

[toykilla]

I am a bit confused.

You said the stock pump flows plenty, but yet you are still running lean? and need a larger pump?

This is a good topic, because we all Know what happens when FI runs lean.. i followed your issues awhile back

 

[Richard 350z]

Hey Max -

Great info. Too bad it went right over my head. LOL

 

[Daking350Z]

I would guess you are running out of injector...The 380's are (in my opinion) Not large enough to flow the fuel requirements you need..Another thing I found is that the fuel, on a returnless style fuel system(which is designed with only emmisions in mind) the fuel dead heads in the fuel rail and heats up. On a return style system you are dumping any unused fuel back into the tank and always getting a fresh supply of COOLER fuel..Hot fuel can lead to detonation in the warmer months..Thats why the preffered method in performance cars is return style fuel systems..As for you going a bit lean up top,why cant TS reflash the injector duty cycle??Are the injectors at their maximum flow rate or is the fuel pump not doing its job??I bet the injectors are juts too small...

 

[MaxHax]

Update:


I went with the Walbro 190L and everything is perfect and in spec and I am no longer lean even at WOT 9PSI.

I am coordinating a video shoot to be made on some WOT runs with EJ as the co-pilot for the camera.

TBA soon!