my car fuel pressure is at 40psi and under boost it holds at about 40 and drops to 36 and goes back up to 40... it fluctuate a little but its mostly in at 40 psi... from my understanding is that each lb of boost the fuel pressure is suppose to go up 1 psi. and when i pull off the vacuum for the fpr it only goes up 3 psi... isn't it suppose to go up 10+psi? i changed my fuel filter, injectors, fpr, checked the lines and fuel pump back to stock and still the same thing. i also checked the voltage on the fuel pump and it was reading 12v and i am also running a resistor box. anybody know what else it could be? could it be a vacuum leak? my setup is listed below.

greddy 720cc injector
hondata 2b w/3 bar
aem fuel rail
aem fpr
bbk 255 lph fp

 

you need a bigger pump

 

y u say i need a bigger pump?? i'm only aiming at about 350whp

but at the time i was on the dyno it was doing a base run @ 255whp only @ 10psi

 

if you've changed everything else and you have your vacuum lines on correctly, that leaves only the pump.

 

well i checked the vacuum lines and i dont think its the vacuum source... how can i make sure its not the vacuum? is there a way to do this?