The OEM tumble generator valves on the Subaru EJ engines create an air flow restriction. Radium Engineering TGV housings feature a smooth bore and permit the option to use secondary injectors for high fuel demands. These TGV housings were designed in-house and utilize die-cast manufacturing to achieve shapes and features not possible with other manufacturing methods. The inner bores are perfectly smooth without machining marks. Even with the extra features, they are 56% lighter than OEM TGVs and 14% lighter than CNC billet variations.

The outer mounting bosses on the TGV housing have been redesigned to provide additional clearance for larger turbo inlet pipes. Dual port injection (per runner) capability make these a good match for high power engines using alternative fuels. However, they can also be used in a standard single injector configuration. The eccentric threaded blocks make these TGV housings compatible with a wide variety of Subaru EJ intake manifolds.

NOTE: Because the TGV potentiometers and DC motors are removed, ECU tuning is required.



These TGV housings are bare aluminum with a satin finish. If the user would like to add a surface treatment of their own (paint, powder coat, etc) know that die-cast aluminum alloy is not compatible with anodizing.

These TGV housings utilize a Cerakote black coating originally formulated in Oregon, USA for the firearms industry. Cerakote is a state-of-the-art polymer-ceramic composite coating. It is only 0.001" thick and exceeds powder coat with resistance to abrasion, wear, chemical, and corrosion and is superior in impact strength and hardness.



The fuel rails are CNC machined from solid 6061 aluminum, black anodized, and laser engraved for a high quality surface finish. They are compatible with all fuel types including alcohol mixtures such as E85 and is a necessary modification for those using methanol on high powered engines. The end ports are manufactured with large high flowing 10AN ORB end ports.

The top auxiliary ports are threaded with 8AN ORB for ancillary accessories such as Fuel Pulse Dampeners. Press-fit spacers are included to thermally insulate heat transfer into the fuel rails.



Each fuel rail has 4 injector ports that are machined to permit injectors with 14mm O-rings.

Primary Lower Fuel Injectors:

Using the provided adapters, both OEM Subaru or 60mm Bosch EV14 style fuel injectors can be used. To reuse the OEM Subaru injectors, the provided top hat must be installed over the upper OEM injector O-ring and the provided injector seat must be installed over the lower injector O-ring. Below are compatible aftermarket injectors for the lower primary ports.

  • Injector Dynamics ID1050-60-14-14
  • Injector Dynamics ID1300-60-14-14
  • Injector Dynamics ID1700-60-14-14
  • Injector Dynamics ID2600-60-14-14


Secondary Upper Fuel Injectors

Only 34mm Bosch EV14 style fuel injectors can be used. Fortunately, many Subaru owners are currently already using Injector Dynamics XXXX.48.11.WRX fuel injectors. If the upper and lower billet caps are pulled off, the base injector is a 34mm Bosch EV14 which can be used. Below are the compatible secondary upper injectors.

  • Injector Dynamics ID1050-34-14-14
  • Injector Dynamics ID1300-34-14-14
  • Injector Dynamics ID1700-34-14-14
  • Injector Dynamics ID2000-34-14-14


Kit Includes:

Both 20-0689-00 and 20-0689-01 include the following:

  • Aluminum Fuel Rail Housings (x2)
  • Black Laser Etched Aluminum Fuel Rails (x2)
  • Injector Seats for Aftermarket Injectors (x4)
  • Injector Hats with Filter Screens for OEM Injectors (x4)
  • Insulating Press-In Spacers (x4)
  • Aluminum Eccentric Manifold Blocks (x2)
  • Dual Port Injection 2AN ORB Plugs (x4)
  • Cylinder Head Gaskets (x2)
  • Flanged JIS Hex Head Bolts (x4)
  • Stainless Steel Hardware
  • FKM O-ring Seals
SKU 20-0689-01
Brand Radium Engineering
Shipping Weight 2.0000kg
Unit Of Measure ea

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