Brian Crower

Subaru EJ257

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 #
	Street/Strip Specification Plug and play application. Short duration for nice street manners, slight lope at idle. Excellent all purpose spec. OEM spring OK.	BC0621 114°	272°/272°	222°/222°	.400”/.400”	10.16/10.16	BC0600
	Race Specification Longer duration profile, added rpm potential. Intended for fully built engine. Tuning and ECU mods recommended. Requires kit BC0600.	BC0622 114°	280°/280°	234°/234°	.425”/.425”	10.80/10.80	BC0600
	USDM EJ257 ('05-up STi)	Stock	256°/256°	204°/208°	.378”/.385”	9.60/9.78
	JDM EJ254	Stock	256°/256°	211°/209°	.374”/.371”	9.50/9.42

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

Spring Pressure:
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

• BC 4340 billet steel crankshaft (83mm stroke). Not a reworked OEM EJ25 crank.
• BC 4340 Econo or Pro Series steel billet rods w/ARP 220,000 psi fasteners.
• CP aluminum forged pistons (any bore size, any compression ratio).
• 9310 nickel carbon steel alloy wrist pins.
• Ductile iron plasma top rings, tapered second ring, low tension oil rings.
• Typically includes aluminum buttons/rail supports (not locks).
• Fully system balanced and ready to install.

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.

Stock Specifications:
EJ25 99.5mm Bore x 79mm Stroke - 7.913” Block Height

 

LEFT COLUMN