Yeah. Your fuel pump maxes out at around 120psi, at 110 psi, its still usable for the HP #'s you'd be putting out. My guess would be that in my setup, if I was running 105-110psi at the fuel rail (that'd be around 9psi of boost using a 12:1 FMU) I'd be maxing the pump out back at the tank. That means I would be getting barely any volume of fuel up to the rail causing a lean condition even with the pressure being high enough. I used -06 AN fittings on my test port adapter because I will be upgrading to -06 stainless steel braided fuel lines with a high flow fule filter in the near future. That alone should stop my pressure drop.

I recall reading somewhere that the stock fuel filters are only good up to 100psi and can only flow around 2LPM(120LPH)@60PSI so its pretty much maxed out on any FMU setup, causing serious flow restrictions. I plan on using a high pressure(200psi), high flow (1500lb/hr)fuel filter like the aeromotive #12308. There are tons to choose from at jegs.com and summitracing.com

Jamie-
-AUTOMATIC turbo'd 95 Talon ESI@8psi (stock internals)14.0sec=1/4 mile

-2003 Mitsubishi Evo VIII