Click Here to download installation instructions (PDF).
Depending on the vehicle's country of origin, this fuel rail kit is compatible with the following Subaru models:
2002-2014 Impreza WRX (that came with top feed injectors)2007-2015 Impreza WRX STi (that came with top feed injectors) 2007-2012 Legacy GT (that came with top feed injectors)2007-2012 Outback XT (that came with top feed injectors)2006-2013 Forester XT (that came with top feed injectors)JDM STi Spec-C Intake Manifold (when used with this adapter HERE)Each rail features a large internal diameter bore to suit even the most fuel hungry engines. They are CNC machined from solid 6061 aluminum, black anodized, and laser etched for a high quality surface finish. All 3 ports on each fuel rail are tapped with -8AN ORB.
For thermal insulation, machined phenolic spacers and washers are included to completely isolate the fuel rail from heat transfer via the TGV housings and mounting bolts.
Two sets of these press-fit phenolic spacers (8 total) and matching hardware are included to suit different height fuel injectors. All must use 11mm diameter upper O-rings just like the OEM Subaru top feed injectors. The fuel rail kits are compatible with all fuel types including popular alcohol mixtures such as E85.
-Black Anodized Laser Etched Aluminum Fuel Rails (x2)-Phenolic Thermal Insulating Press-In Spacers, Tall (x4)-Phenolic Thermal Insulating Press-In Spacers, Short (x4)-Phenolic Thermal Insulating Press-In Bolt Washers (x4)-Stainless Steel M8x1.25 Mounting Bolts, Long (x4)-Stainless Steel M8x1.25 Mounting Bolts, Short (x4)
-Black Anodized Laser Etched Aluminum Fuel Rails (x2)-Phenolic Thermal Insulating Press-In Spacers, Tall (x4)-Phenolic Thermal Insulating Press-In Spacers, Short (x4)-Phenolic Thermal Insulating Press-In Bolt Washers (x4)-Stainless Steel M8x1.25 Mounting Bolts, Long (x4)-Stainless Steel M8x1.25 Mounting Bolts, Short (x4)-Black Anodized Aluminum 6AN Male Fittings (x4)-Black Anodized Aluminum 8AN ORB Plugs (x4)
The 20-0167-01 kit includes enough to plumb the rails in "Parallel, Flow-Through" or "Series". Refer to the More Details tab above for more information. If -8AN male fittings are required, they can be purchased here 14-0152. Two of the plugs can be used if the fuel rails will be plumbed in "Parallel, Dead End", as shown. The other two plugs can be used for the lower center ports if a fuel pulse damper is not used.
NOTE: Neither fuel rail kit comes with hoses.
The opening and closing of the injectors creates pressure pulses in the fuel rail, which can lead to unstable fuel pressure. In order to achieve a safe and consistent rail pressure, a pulse damper should be used (especially with high flow injectors). The internal diaphragm will absorb oscillating pulses and stabilize fuel pressure. This correction can be measured throughout the RPM range and can often help an erratic surging idle. The optional Radium 20-0176 fuel pulse damper can be used in any of the three -8AN ORB ports on the Subaru fuel rails.
If the OEM 2-bolt flanged FPR will be reused, select one of the OEM FPR options above. The 20-0301 OEM FPR adapter is commonly used with EJ20 engines and 20-0303 is used with EJ25 engines (excluding STi). MEASURE YOUR OEM FPR BEFORE ORDERING. These adapters can be used in any of the ports and permits properly clocking for appropriate fitment.
Subaru Fuel Rail Plumbing
Because there are multiple ways to configure fuel hose routing, Radium Engineering does not include hoses in the Subaru kit. Radium offers a selection of pre-made PTFE hoses HERE, but does not offer custom made hoses or bulk-hose. To adapt -6AN hoses to the OEM feed and return hoses, use two Radium 14-0146 5/16" SAE quick disconnect fittings. Note: Subaru used barb fittings on early models.
Hose routing can be configured to mimic the factory flow path, as shown below. This is referred to as a flow-through series configuration. The Radium FPR adapter must be purchased if using the stock fuel pressure regulator.
Similar to the OEM flow-through configuration, the rails can also be used in series with an aftermarket regulator, as shown.
Alternatively, the feed line can be split before it reaches the rails using a "Y" fitting, as shown. This creates a parallel flow-through system. The lines would then join back together after the fuel rails with another "Y" fitting or with the Radium Multi-Pump Regulator.
The last configuration is a parallel dead-end system, as shown below. If the regulator is mounted in the rear of the vehcile, another "Y" fitting could be used to split the feed line into two in the engine bay.