I am new to the Scooby world of mods. But I was wondering if it would be good to run a boost dependent fuel regulator? Its one the bumps the fuel pressure a set amount per amount of boost... Let me know. I would like to safeguard my engine before I go bigger...

Scott

 

The WRX (like most cars) already has a 1:1 rising rate fuel pressure regulator. Modern EFI systems are designed to run with the fuel pressure at 43.5 psi (3 bar) above manifold vac/pressure. When the manifold has a vacuum of -10 (almost -0.07 MPa on the stock boost gauge), fuel pressure is about 33.5 psi. When the manifold is at 0 boost (0 on boost gauge or normal ATM pressure), fuel pressure is 43.5 psi. When the manifold is at 14.5 psi of boost (1 bar or 0.1 MPa), fuel pressure is about 58 psi.

The reason for doing this is to maintain the 43.5 psi pressure difference between the fuel pressure in the fuel rails and the air pressure at the tip of the injector. It also keeps the fuel injector flow rates stable for a given injector pulse width.