Segment:
Performance Compact Sedan/Wagon
Competitors:
Mitsubishi Lancer Evolution, Honda Civic Si, Volkswagen GTI, Mazdaspeed3.
Brand Perception:
Known for its rally heritage, all-wheel-drive system, turbocharged performance, and driver engagement.
Drivetrain:
Symmetrical All-Wheel Drive (SAWD) with Driver Controlled Center Differential (DCCD).
Engine:
2.5L turbocharged Boxer engine (EJ257).
Transmission:
6-speed manual transmission.
Brakes:
Brembo front and rear brake system.
Suspension:
Performance-tuned independent suspension.
Engine Mechanical:
Detailed overhaul and repair procedures for EJ257 engine, including short block, cylinder heads, valvetrain, pistons, connecting rods, crankshaft, timing belt, oil pump, cooling system.
Engine Management:
ECU diagnosis, fuel injection system, ignition system, emissions control systems (EVAP, secondary air injection), sensor and actuator testing, wiring diagrams.
Transmission:
6-speed manual transmission (TY856WB1CA) overhaul, clutch system, gear selection mechanism, driveline components (driveshafts, differentials).
Suspension:
Front and rear suspension systems, struts, springs, control arms, sway bars, bushings, wheel alignment procedures.
Brakes:
Front and rear brake systems (Brembo calipers standard on STI), ABS, EBD, brake rotor/pad replacement, caliper overhaul, brake fluid bleeding.
Steering:
Power steering system, steering rack, steering column, alignment.
Electrical:
Complete electrical system, battery, charging system, starter, lighting, power windows, locks, mirrors, audio system, SRS airbag system, body control modules, comprehensive wiring diagrams.
Body:
Body panel removal and installation, exterior trim, doors, hood, trunk, bumpers, interior trim, seats, HVAC system, diagnosis and repair of body electrical components.
HVAC:
Air conditioning system, heater, climate control, refrigerant handling, component testing and replacement.
Safety Systems:
Airbag system diagnosis and service, seat belt mechanisms.
Maintenance:
Scheduled maintenance procedures, fluid changes (engine oil, coolant, transmission fluid, brake fluid, differential fluid), filter replacements, spark plug replacement, belt inspection/replacement.
Diagnostics:
Troubleshooting guides based on symptoms, diagnostic trouble codes (DTCs), on-board diagnostics (OBD-II) interpretation, component testing procedures.
Repair:
Step-by-step instructions for component removal, disassembly, inspection, repair, reassembly, and installation for all major vehicle systems.
Overhaul:
Complete engine and transmission overhaul procedures, including torque specifications, clearances, and critical assembly data.
Adjustment:
Clutch adjustment, parking brake adjustment, idle speed adjustment (if applicable), suspension alignment.
Calibration:
ECU relearn procedures, idle air control (IAC) valve relearn, throttle body relearn.
Depth:
Comprehensive. Covers everything from routine maintenance and diagnostics to complete engine and transmission rebuilds, detailed electrical schematics, and bodywork repair.
Target Audience:
Professional technicians and experienced DIY mechanics.
Engine Type:
Horizontally-opposed (Boxer), turbocharged, intercooled, DOHC, 16-valve.
Displacement:
2.5 Liters (2457 cc)
Horsepower:
305 hp @ 6000 rpm (JDM/Euro), 293 hp @ 6000 rpm (USDM)
Torque:
290 lb-ft @ 4000 rpm (JDM/Euro), 287 lb-ft @ 4000 rpm (USDM)
Fuel Delivery:
Multi-point fuel injection (MPI), sequential.
Fuel Type:
Premium Unleaded Gasoline (91 octane or higher recommended)
Turbocharger:
IHI VF39 (USDM), VF36 (JDM/Euro)
Intercooler:
Top-mount, air-to-air.
NHTSA Front Crash Test:
5-Star (2007 Impreza Sedan)
NHTSA Side Crash Test:
5-Star (2007 Impreza Sedan)
IIHS Front Crash Test:
Good (2007 Impreza Sedan)
IIHS Side Crash Test:
Good (2007 Impreza Sedan)
ABS:
Standard, 4-wheel Anti-lock Braking System.
Ebd:
Standard, Electronic Brake-force Distribution.
Traction Control:
Standard, with DCCD and AWD system integration.
Airbags:
Front dual-stage airbags, front side-impact airbags, side-curtain airbags (sedan).
Seatbelts:
3-point height-adjustable front seatbelts with pre-tensioners, 3-point rear seatbelts.
Child Anchors:
LATCH (Lower Anchors and Tethers for Children) system.
Engine Oil Change:
Every 3,000-5,000 miles or 3-6 months, depending on driving conditions (severe vs. normal).
Engine Oil Filter:
Replace with every oil change.
Air Filter:
Inspect every 15,000 miles, replace as needed or every 30,000 miles.
Cabin Air Filter:
Inspect every 15,000 miles, replace as needed or every 30,000 miles.
Spark Plugs:
Iridium type, replace every 60,000 miles.
Timing Belt:
Replace every 60,000 miles or 5 years (critical item for EJ engines).
Coolant Flush:
Every 30,000 miles or 3 years (using Subaru Super Coolant or equivalent).
Transmission Fluid:
Every 30,000-45,000 miles (manual transmission).
Differential Fluid Front Rear:
Every 30,000-45,000 miles.
Brake Fluid:
Every 30,000 miles or 2 years.
Engine Oil:
SAE 0W-30 (Synthetic recommended for performance applications), API SG, SH, SJ, SL, or SM certified.
Engine Oil Capacity:
5.5 US quarts (5.2 liters) with filter.
Coolant:
Subaru Super Coolant (Blue) or equivalent long-life silicate-free coolant.
Transmission Fluid:
API GL-5, SAE 75W-90 (synthetic recommended).
Differential Fluid Front Rear:
API GL-5, SAE 75W-90 (synthetic recommended).
Brake Fluid:
DOT 3 or DOT 4.
Engine:
Head gasket failures (less common on EJ257 compared to EJ253, but still possible), ringland failure under aggressive tuning/abuse, turbocharger wear (VF39/VF36), piston slap at cold start.
Transmission:
Clutch wear, synchro wear on certain gears (especially 2nd and 5th/6th) with hard use, differential wear with aggressive driving.
Suspension:
Bushing wear, premature shock absorber failure under aggressive driving, wheel bearing failure.
Electrical:
Alternator failure, MAF sensor issues, occasional ECU glitches.
