A series of low-volume versions with even greater power and grip were built by Subaru's in-house modifier, Subaru Tecnica International (STi). STi versions of the Impreza, which produced 280 PS (206 kW) from new, are often raced, largely unmodified, in the Group N class in various rally championships to great success. Introduced in 1994, the STi has proven to be a very popular high-performance machine in the Japanese domestic market. Introduced to the United States in 2004, the US model STi features the larger displacement 2.5L (EJ257) that features AVCS.
Note: Intake camshafts are setup for non AVCS operation. If running AVCS, you must completely remove the four set screws located in the front of each intake cam (dowel pin side) using a 2.5mm Allen wrench. This will allow oil to actuate the Active Valve Control System.
|Stage||Description||Cam #||Adv. Dur.||Dur @ .050||Lift (in)||Lift (mm)||Kit #|
Plug and play application. Short duration for nice street manners, slight lope at idle. Excellent all purpose spec. OEM spring OK.
Longer duration profile, added rpm potential. Intended for fully built engine. Tuning and ECU mods recommended. Requires kit BC0600.
|USDM EJ257 ('05-up STi)||Stock||256°/256°||204°/208°||.378”/.385”||9.60/9.78|
Bucket Diameter: 1.220”
The above cams work with AVCS.
VALVE SPRING/RETAINER KIT
Designed for high rpm, BC valve springs are wound from only the highest grade, super clean, chrome silicone alloy and feature proprietary processing procedures for consistent pressures. BC titanium retainers are CNC machined from 6AL4V round bar titanium to exacting tolerances.
|Kit #||Spring #||Retainer #||Description|
|BC0600||BC1600||BC2300-16||Single spring, titanium retainer|
BC1600 Seat: 1.420” @ 60 lbs / Open: 1.000” @ 160 lbs / Coil Bind: 0.860” (no machine work required)
STAINLESS STEEL VALVES
BC valves are made from premium stainless steel, fully machined and swirl polished for ultimate air flow. Dished head for added weight savings and increased valve control at high rpm. Standard and oversize head.
|Part #||Description #|
|BC3620||36.0mm Intake (standard head diameter)|
|BC3621||32.0mm Exhaust (standard head diameter)|
|BC3624||37.0mm Intake (+1mm head diameter)|
|BC3625||33.0mm Exhaust (+1mm head diameter)|
SUBARU EJ25 2.71L STROKER KIT
|Kit #||Crank #||Rod #||Piston #||Desc.|
|BC0628||BC5629||BC6608||BC7629||83mm stroke w/ BC625+ rod|
|BC0629||BC5629||BC6609||BC7629||83mm stroke w/ bROD rod|
The BC stroker kit for the Subaru EJ25 engine utilizes a custom, 83mm monster stroke, steel billet crankshaft, not a reworked factory EJ25 crank. Depending on bore size that you decide, the BC kit will take you up to a 2.71L with a safe 102mm bore. As usual, each BC kit features custom CP forged aluminum pistons, premium alloy wrist pins, full ring pack and buttons. Big time power and torque gains. BC Econo rods rated to 600 horsepower, BC Pro Series rods rated to 800+ horsepower.
EJ25 99.5mm Bore x 79mm Stroke - 7.913” Block Height