Description
Radium Engineering developed the Fuel Pressure Regulator Kit for 2008–2021 Subaru WRX STI EJ257 around the needs of modified street and competition cars, where component compatibility and clean system layout matter as much as outright capacity.
Why This Upgrade Matters
Fuel pressure control is fundamental to injector consistency and repeatable tuning. A regulator must manage return flow while maintaining the pressure strategy required by the injectors and ECU, particularly as pump flow and engine demand increase.
Product-Specific Details
Radium Engineering 08-21 Subaru WRX STi (EJ257 Only) RA-Series Fuel Pressure Regulator Kit
Fitment & Application
Application: 2008–2021 Subaru WRX STI EJ257
Fitment style: Application-Specific
Technical Notes
Base pressure should be set with the system configured as required by the engine management strategy. Pump flow affects the regulator' operating range, and boosted applications may require a manifold-reference connection where the specific regulator supports it.
Radium Part Number
RAD20-0965
Enthusiast Notes
For tuned cars, stable pressure is part of stable fueling. Set the regulator with a gauge or sensor and validate pressure behavior under load rather than assuming the static setting tells the whole story.
Before Ordering
Confirm required base-pressure range, total pump flow, feed/return port sizes and whether vacuum/boost reference is required. A regulator should be sized as part of the complete fuel system.