If I am running with a walbro 255lph in the tank and not the auxiliary in-line fuel pump supplied with the kit, how does my fuel line hook-up change? Someone tried explaning it to me, but it didn't quite make sense (in essence, his explanation made it sound like the FMU was to be attached on the outlet side) A diagram would be helpful.

If I am doing prelim part installs (i.e., everything but the blower), I assume I can hook-up the FMU completely. However, I need to hook up the vacuum lines, too, right? How do I close those off effectively if I don't have the BOV in place?

 

Stock:
in-tank fuel pump > filter > rail w/ stock FPR > return

With normal Stillen kit:
in-tank fuel pump > filter > in-line fuel pump > rail > FMU > return

With Walbro and FMU:
in-tank Walbro > filter > rail > AFPR* > FMU > return
*an Aftermarket Fuel pressure regulator is a good idea to lower the pressure back down to stock at idle.

An FMU will not affect anything unless there is boost pressure going to it, so hooking it up NA will do absolutely nothing good or bad.

 

Thanks a lot. do you have a recommendation for a good aftermarket FPR? I assume it completely replaces the stock unit.

 

You'll want to find something that will bring the fuel pressure to 34psi at idle.
I picked up an Aeromotive fpr but it could not bring down the psi below 38. I picked up an AEM fpr to replace it but haven't installed it yet.

Update: I got the Aeromotive fpr down to 34psi so its good!

 

So you went with the AEM universal? Just checking to make sure I pick the right stuff for this application. How do you adjust fuel pressure for idle?

 

Most fpr's have an adjustment screw on top like the AEM one:


You just use a hex key to turn the screw to lower the psi. There are some fpr's out there that don't have an adjustment screw.

 

The Aeromotive one I picked up was advertised that it would go down to 30psi but I could only get as low as 38psi.


Update: I got it down to 34psi.

 

To aid my understanding of how this works fundamentally... this fpr is hooked up exactly the same way as the stock fpr? or does it require additional connectors. I guess my question is, how does this thing determine your car is at idle...

 

My setup:
Fuel Filter ===>Front Fuel Rail/Back Fuel Rail===>AFPR===>FMU===>Fuel Return Line.
I'm not reusing the Vortech FMU.

The stock fpr is replaced by a fuel rail adapter (example)
The adapter in the pic is slightly different than the one I got from the member, SXR7, which is a hose barb and so I have to use a rubber hose.

 

Pics aren't showing up , anyone have them saved ? There's got to be a tee or something I'm not seeing , because how does the vortech fmu increase fuel flow/pressure beyond what the afpr is set at?