fuel pressure before and after rail?

[duduglanza]

Hi , does anyones know what is the fuel pressure of a walbro 255 pump before the fuel rail as i will be doing an inline gauge before the fuel rail

 

[AdamB]

The fuel pressure before the rail will be set by the fpr, as long as the fuel rail doesn't run dry it doesn't make a difference what the pressure is after the rail.
It is possible to run a fpr before the rail, this method is supposed run the fuel cooler, but never tested it myself.

 

[wildchild]

dunno about the pump but usually pressure is set at 3.5 at the gauge after the rail.