Radium Engineering Fuel Pressure Regulator Kit (Black), 2008-2021 STi

This kit replaces the OEM fuel pressure regulator and damper assembly. The factory STi fuel line routing uses a quasi-dead-end system that circulates fuel through the regulator, bypassing the engine. Fuel is only routed to the engine when there is demand.
The Radium FPR kit reroutes fuel to cycle through the fuel rails before reaching the regulator and returning to the tank. This is the preferred fuel line routing by Subaru tuners trying to address stumbling issues. The kit installs in the same location as the OEM fuel pressure regulator. Also included are vacuum hose and fittings to reroute the vacuum reference line from the #4 cylinder runner to the intake manifold plenum for a more stable vacuum signal. The optional pressure gauge kit 20-0386 (sold separately) can be installed into the unused 8AN ORB port on the regulator.
The regulator features the first tool-less pressure adjustment. A jam nut and set screw are no longer required. With a simple turn of the knob, pressure will be increased or decreased.

Included:
• Fuel Pressure Regulator
• Hoses
• Fittings
• Necessary Hardware for install

Features:
There are 4 interchangeable 10-32 threaded vacuum port fittings provided to cover all scenarios.
• Barbed Fitting: A black zinc-plated 3/16" (5mm) barb machined from high strength steel that is compatible with the following vacuum hoses: 5/32" (4mm), 3/16" (5mm), and 7/32" (6mm)
• 3AN Male Fitting: A black zinc-plated adapter machined from high strength steel that is compatible with 3AN hose ends
• Push-To-Connect: A nickel-plated brass fitting with Buna-N O-rings that is compatible with hard plastic 1/4" OD tubing
• Vacuum Plug: A black oxide stainless steel screw that is used to maintain a constant (non dynamic) fuel pressure.