Radium 20-0965 RA-Series Fuel Pressure Regulator Kit for 08-21 Subaru WRX STI

Vehicle Fitment

• 2008-2021 Subaru WRX STI (EJ257, 2.5L H4 Turbo)

Fitment Notes

• Direct bolt-in replacement for OEM fuel pressure regulator
• Compatible with OEM fuel rail configuration
• Supports both return and returnless-style systems when modified accordingly
• Not compatible with FA20DIT or WRX non-STI models

Features

• Precision RA-series regulator designed for high-flow fuel systems
• Compatible with gasoline and ethanol-based fuels (E85 safe)
• Adjustable base pressure from 18-120 psi
• Boost reference port for 1:1 fuel pressure compensation under boost
• Machined from 6061 aluminum with black anodized finish
• Includes integrated 1/8" NPT port for optional fuel pressure sensor or gauge
• Factory-style mounting bracket for OEM-like installation
• Preassembled with fuel fittings and hoses for plug-and-play setup

Specifications

• Series: RA-Series
• Fuel Compatibility: Gasoline, ethanol blends (including E85)
• Adjustment Range: 18-120 psi
• Port Size: 6AN ORB inlet/outlet
• Reference Port: 1/16" NPT vacuum/boost fitting
• Sensor Port: 1/8" NPT (plug included)
• Material: CNC-machined 6061 aluminum
• Emissions Compliance: Not CARB legal -- not for use on pollution-controlled vehicles

Included Components

• 1x RA-Series fuel pressure regulator
• 1x OEM-style bracket and mounting hardware
• 2x Pre-cut fuel hoses
• 4x Fittings for 6AN ORB ports
• 1x 1/8" NPT plug
• 1x Vacuum reference fitting
• 1x Installation instructions

Product Description

The Radium Engineering 20-0965 RA-Series Fuel Pressure Regulator Kit is a high-performance drop-in solution for the 2008-2021 Subaru WRX STI with the EJ257 turbocharged engine. This regulator delivers consistent fuel pressure in high-horsepower builds while maintaining full compatibility with the factory fuel rail layout. The RA-Series regulator provides adjustable pressure and a 1:1 vacuum reference port for precise fuel tuning under boost.

Engineered for demanding applications, this kit includes preassembled hoses, fittings, and a vehicle-specific bracket for true plug-and-play installation. It supports fuels ranging from pump gas to ethanol blends like E85. Whether you're building a high-boost street car or a dedicated track machine, the 20-0965 delivers the flow, reliability, and adjustability required for serious Subaru performance builds.