i just got this adjustable fpr from a friend and i had a couple of questions. which spout is the inlet and which is the outlet? what fuel pressure should i run at? my car info is in my sig. btw, i have a walbro 255 fp if that matters.

 

i believe stock fp is around 40psi.

 

Stock static fuel pressure is 36psi. Unless you have a fuel controller or standalone, you should stick to that.

 

ok, thanks ill stick to 36psi. also, it looks like it has a vacuum nipple. does that make it a rising rate? what about the inlet and outlet?

 

anyone?

 

does the vacuum nipple make it a rising rate? what about which is the inlet and outlet?

 

the nipple at the top of your picture, the bottom of the regulator, farthest from the adjustment screw is the outlet that returns to the fuel take. The one that is on the back side opposite of the gauge should be the inlet. You can tell because the outlet is farthest from the adjustment screw.

Also, the nipple on the side of it is used for a vacuum source, that is so when it pulls vac the pressure is lower, and when it senses boost it pushes up the fuel pressure extra to compensate.

 

No, all FPR's need to be connected to a manifold pressure source or they'll do nothing. The FPR's job is to keep the fuel pressure a constant amount above manifold pressure.