Click here to download installation instructions (PDF)
These plumbing kits are designed to compliment Radium Engineering Subaru EJ fuel rail installations. Both kits interface with the factory feed and return hard lines in the engine bay (near the LH strut tower) and provide all the underhood fuel plumbing. All necessary fittings and hoses are included, along with an adjustable high-flow fuel pressure regulator.
Two kits are offered; one that feeds the fuel rails in series, and another that feed the fuel rails in a parallel configuration. Both kits perform equally well. The end decision is based on personal preference. Scroll down for details on each kit.
Both kits are compatible with all Radium Fuel Rails for the Subaru EJ engines (excluding 20-0499 Fuel Rails).
IMPORTANT NOTES:
1. Neither kit includes a fuel filter.
2. Neither kit is compatible with Radium dual port injector fuel rail kit 20-0499.
3. Both kits are safe to use with alcohol fuels such as methanol, ethanol, E85 etc.
4. Both kits use 3/8″ (6AN) high pressure EFI fuel hose.
20-0578 FUEL RAIL PLUMBING KIT, SUBARU EJ, SERIES
This kit is compatible with Subaru platforms that use an EJ motor. For early vehicles with an engine bay mounted fuel filter, consult the installation instructions.
This kit interfaces with the factory hard lines near the LH strut tower using SAE quick connects or older hose barb connections. An adjustable Radium Direct Mount Regulator (DMR) and Radium 0-100psi fuel pressure gauge are included. The fuel pressure gauge can be installed at any of the 6AN junctions before the regulator using the included adapter. The 6AN swivel fuel rail fittings are low profile making them ideal for the tight spaces associated with the EJ motor. The variety of reuseable PushLok hose ends permit customizing (such as adding a flex fuel sensor) making installation quick and painless. The included 6AN fuel hose can be cut with standard tools and assembled without special skills. Unlike standard low-quality rubber fuel hose that degrades with alternate fuels, the provided hose is resistant to all fuels including E85.
The contents of the 20-0578 kit are shown in the photo below.
20-0584 FUEL RAIL PLUMBING KIT, SUBARU EJ, PARALLEL
Because of the regulator mounting location and OEM fuel filter placement, the parallel fuel rail plumbing kit is only compatible with the 2008+ Impreza (WRX/STi) and Forester platform. 
Because the hoses and fittings are consolidated, the parallel kit is a good option for cleaning up the engine bay. Each fuel rail is fed as shown in the photo above. The feed and return lines enter the Radium Multi-Port Regulator (MPR) from the rear and output through the front to the fuel rails.
As shown above, the regulator secures to the LH strut tower using the provided stainless steel mounting bracket. A Radium 0-100psi fuel pressure gauge is included for calibration. Fittings and 6AN hose are included to interface with the OEM feed and return hard lines. If aftermarket -AN hoses/lines have replaced the factory piping, this kit can still be used (contact [email protected] for details).
The contents of the 20-0584 kit are shown below.
