Radium Engineering Top Feed Fuel Rail Upgrade | 2001-2006 Subaru WRX / STI EDM/JDM (20-0577-02)

The EJ's factory fuel rails were never sized for the injectors a built Subaru actually runs.

Big top feed injectors need a rail with volume and real ports behind them. The Radium Engineering Top Feed Fuel Rail Upgrade for factory top feed EJ engines is a machined aluminum rail pair with three 8AN ORB threaded ports per rail, six total, ready for feed lines, a direct mount regulator, pulse dampers, or gauge adapters in whatever arrangement your system calls for. This is an upgrade rail, meaning your factory or OEM-equivalent injectors carry over. Thermal insulating spacers keep manifold heat out of the fuel. The rail your EJ fuel system should have started with.

What You'll Feel

• Stable fuel delivery across all four injectors with volume the factory rails lack
• Real plumbing freedom, with six 8AN ORB ports to configure feed, return, damping, and monitoring
• Cooler fuel from thermal insulating spacers isolating the rails from the hot intake manifold
• A straight swap using your existing factory-size injectors
• Clean integration with Radium's Subaru parallel plumbing kits and regulators

Features

• Machined aluminum fuel rails for Subaru EJ engines with factory top feed injectors
• Three 8AN ORB threaded ports per rail (six total) accepting Radium adapters, direct mount regulators, dampers, and gauge fittings
• 20-0567-02: 8AN ORB port machined in the underside center of each rail
• Upgrade-style rail: compatible with factory or OEM-equivalent injectors (same height and O-ring dimensions)
• Thermal insulating spacers included to limit intake manifold heat transfer
• OEM 2-bolt flange regulator reusable with Radium adapter 20-0303 (sold separately)

The Details

Radium builds two families of Subaru rails, and knowing which you need saves a return. Upgrade rails, like this one, fit engines that already run top feed injectors from the factory and reuse OEM or OEM-equivalent injectors; conversion rails are for switching side feed or air-assist engines to top feed and are a different product. Injector selection follows one hard rule: same height and same upper and lower O-ring diameters as OEM, and Radium defers to your injector supplier and tuner for brand and flow specifics. One clearance note decides between the two variants of this rail: the center lower port bulge on the 20-0567-02 can interfere with the early AVCS solenoids on the EJ207 and JDM EJ205, and those engines should use the top-port 20-0577-02 instead, which shares identical mounting and injector spacing but relocates the third port to the top of each rail. Certain JDM STI and EJ253 applications running the 20-0577-02 also require the 20-0372 adapter set. Fittings, plumbing, and injectors are sold separately.

Kit Includes

• 2x Machined aluminum top feed fuel rails (port location per selected variant)
• Thermal insulating spacers and mounting hardware
• Fittings, plumbing, and injectors NOT included, sold separately

Applications

• 20-0567-02: 2002-2014 Subaru Impreza WRX (USDM), 2007-2014 WRX (JDM/EDM), 2007-2021 WRX STI, 2006-2013 Forester XT, 2001-2003 Legacy GT (JDM), 2007-2012 Legacy GT and Outback XT, 2005-2006 Saab 9-2X Aero
• 20-0577-02 (top port): 2001-2006 Impreza WRX (JDM/EDM), 2001-2006 WRX STI (EDM), 2001-2002 WRX STI (JDM); with 20-0372 adapters: 2003-2006 WRX STI (JDM), 2004-2011 Impreza EJ253, 2005-2010 Forester EJ253, 2005-2012 Legacy EJ253, 2006-2009 Outback EJ253
• Factory top feed EJ engines only; EJ207 and JDM EJ205 with early AVCS require the 20-0577-02 top-port variant