Radium Engineering 20-0978 Fuel Rail Plumbing Kit for 02-14 Subaru WRX/04-21 STi

Vehicle Fitment

• 2002-2014 Subaru Impreza WRX (EJ20/EJ25)
• 2004-2021 Subaru Impreza WRX STI (EJ25)
• Subaru Forester XT / Legacy GT with EJ turbo engines

Fitment Notes

• For use with Radium Engineering Subaru EJ fuel rails only
• Not compatible with Radium dual port injector fuel rail kit 20-0499
• Series plumbing configuration (fuel flows through both rails sequentially)
• Parallel version available: Radium 20-0984
• Interfaces with factory feed/return hard lines near LH strut tower
• Compatible with SAE quick-connect and older hose barb connections
• Early vehicles with engine bay-mounted fuel filter -- consult installation instructions
• Does not include a fuel filter
• Not CARB legal -- not for sale in California

Features

• Complete underhood fuel plumbing for Radium EJ fuel rails
• DMR-RA regulator with tool-less pressure adjustment
• 1 psi per detent incremental adjustment with haptic feedback
• 360° swiveling vacuum reference port (double O-ring sealed)
• 0-100 psi fuel pressure gauge included
• Low-profile 6AN swivel fuel rail fittings for tight EJ clearances
• Reusable PushLok hose ends for easy customization
• E85, methanol, and ethanol compatible
• 6AN fuel hose cuts with standard tools -- no special skills required

Specifications

• Part number: Radium Engineering 20-0978
• Type: Fuel rail plumbing kit (series configuration)
• Fuel line size: 3/8" (6AN) high pressure EFI hose
• Regulator: DMR-RA (Direct Mount, RA-series)
• Gauge: 0-100 psi liquid-filled
• Fuel rail plugs: 8AN ORB (for unused pulse damper ports)
• Factory interface: SAE quick-connect / hose barb
• Fuel compatibility: Gasoline, E85, methanol, ethanol
• Parallel version: Radium 20-0984
• CARB status: Not CARB legal

Included Components

• Radium DMR-RA direct mount fuel pressure regulator
• 0-100 psi fuel pressure gauge with adapter fitting
• 6AN high pressure EFI fuel hose
• 6AN low-profile swivel fuel rail fittings
• Reusable PushLok hose ends
• SAE quick-connect and hose barb adapters
• 8AN ORB fuel rail plugs
• All necessary fittings and hardware
• Installation instructions

Product Description

The Radium Engineering 20-0978 is a series-configuration fuel rail plumbing kit designed for Subaru EJ-powered vehicles equipped with Radium Engineering fuel rails. The kit provides all underhood fuel plumbing needed to connect Radium fuel rails to the factory feed and return hard lines located near the left-hand strut tower, using either SAE quick-connect or older hose barb fittings depending on the vehicle year. In the series configuration, fuel flows through one rail and then the other sequentially before returning through the regulator. The kit includes a Radium DMR-RA direct mount fuel pressure regulator featuring tool-less pressure adjustment -- a simple turn of the knob increases or decreases pressure with incremental detents providing haptic feedback at approximately 1 psi per click. The RA-series regulator also features a 360-degree swiveling vacuum reference port with double O-ring sealing. A 0-100 psi fuel pressure gauge is included and can be installed at any 6AN junction upstream of the regulator using the provided adapter. All fuel hose is 3/8" (6AN) high-pressure EFI rated, and the low-profile 6AN swivel fittings are specifically designed for the tight clearances around the EJ engine. Reusable PushLok hose ends allow easy customization, such as adding a flex fuel sensor inline. The entire kit is compatible with E85, methanol, ethanol, and standard gasoline. Compatible with all Radium Subaru EJ fuel rails except the 20-0499 dual port injector kit. A parallel plumbing version is available under part number 20-0984. Does not include a fuel filter. Not CARB legal.