Radium Engineering Parallel Fuel Rail Plumbing Kit | 2008-2021 Subaru STI (20-0984)

Two rails fed evenly, one regulator on the strut tower, and an engine bay that finally looks planned.

The Radium Engineering Fuel Rail Plumbing Kit, Subaru EJ, Parallel complements a Radium EJ fuel rail installation by feeding each rail in a parallel configuration: the feed and return lines enter the MPR-RA regulator from the rear and output through the front to the fuel rails, with the regulator securing to the LH strut tower using the provided stainless steel mounting bracket. A Radium 0-100psi fuel pressure gauge is included for calibration, and fittings with 6AN hose interface with the OEM feed and return hard lines. Because the hoses and fittings are consolidated, the parallel kit is a good option for cleaning up the engine bay. All hose is resistant to every fuel type including E85. Fuel rails sold separately.

What You'll Feel

• Even delivery to both banks through the parallel feed architecture
• An engine bay cleaned up by consolidated hoses and fittings
• Pressure set with confidence, the included 0-100psi gauge handling calibration
• Factory hard lines interfaced directly, no line fabrication for the stock-piping install
• Adjustable regulation from the strut-tower-mounted Radium multi-port regulator

Features

• Feeds Radium Subaru EJ fuel rails in a parallel configuration (rails with 8AN ORB ports required, sold separately)
• Radium MPR-RA adjustable multi-port regulator with stainless steel LH strut tower bracket
• Radium 0-100psi fuel pressure gauge included for calibration
• Fittings and 6AN hose included to interface with the OEM feed and return hard lines
• Compatible with the 2008+ Impreza (WRX/STi) and Forester platform due to the regulator mounting location and OEM fuel filter placement
• All hose resistant to all fuels including E85

The Details

Radium offers series and parallel kits for the EJ, and both perform equally well, with the decision resting on personal preference: series echoes the factory routing through the Radium DMR, while this parallel kit consolidates everything at the MPR on the strut tower for symmetry and serviceability. Two installation notes from Radium's instructions matter at planning time: there are no provisions included for EVAP, so a new line replaces the hard line under the manifold, and installation places plugs in the rails' unused ports with the swiveling fittings in the rear ports, O-rings oiled throughout. Builds that have already replaced factory piping with aftermarket AN lines can still use this kit by changing the fittings on the regulator where the feed and return lines meet. Pulse dampers, if used, install in the rail bottom ports during the same session.

Kit Includes

• 1x Radium MPR-RA adjustable fuel pressure regulator with stainless mounting bracket
• 1x Radium 0-100psi fuel pressure gauge
• 6AN fuel hose and all fittings to interface with the OEM feed and return hard lines
• Fuel rails NOT included, sold separately

Applications

• 2008-2014 Subaru Impreza WRX STI (EJ)
• 2015-2021 Subaru WRX STI
• Radium Subaru EJ fuel rails with 8AN ORB ports; series version sold separately