Segment:
Performance compact sedan/hatchback, rally-bred sport compact.
Key Selling Points:
All-wheel drive, turbocharged performance, rally heritage, driver engagement.
Rivals:
Mitsubishi Lancer Evolution, Volkswagen GTI, Mazdaspeed3, Ford Focus ST.
Wrx Features:
2.5L turbocharged EJ255 engine, symmetrical all-wheel drive, sport-tuned suspension, upgraded brakes, aggressive styling.
Sti Features:
2.5L turbocharged EJ257 engine (higher output), DCCD (Driver Controlled Center Differential), Brembo brakes, stronger engine internals, 6-speed manual transmission, more aggressive aero.
Powertrain:
Engine mechanical, lubrication, cooling, fuel, ignition, exhaust, emissions control, turbocharger systems, and engine management (ECU).
Transmission Drivetrain:
Manual transmission (TY756 for WRX, TY856 for STI), clutch, differentials (front, center, rear - including DCCD for STI), driveshafts, axles.
Chassis Suspension Steering:
Front and rear suspension (MacPherson struts front, multi-link rear), steering system, wheel bearings, hubs.
Brakes:
Front and rear brake systems (including Brembo for STI), ABS, EBD, brake fluid, hydraulic lines, parking brake.
Electrical Electronics:
Battery, charging system, starting system, lighting, instrumentation, power accessories, body control module (BCM), ECU/ECM diagnostics, CAN bus communication.
Body Exterior Interior:
Body panels, doors, windows, sunroof, seats, interior trim, HVAC, airbags, safety restraints.
Maintenance:
Scheduled maintenance, oil changes, filter replacements, fluid checks and changes, spark plug replacement, belt inspection/replacement.
Diagnostics Troubleshooting:
Systematic troubleshooting guides, diagnostic trouble codes (DTCs) and their meanings, electrical circuit diagrams.
Repair Overhaul:
Detailed step-by-step instructions for major component removal, installation, and overhaul (e.g., engine rebuild, transmission repair, brake caliper replacement).
Special Tools Procedures:
Identification and usage of specialized tools required for specific repairs and adjustments.
Depth:
Comprehensive. Covers everything from basic fluid checks and tire rotations to in-depth engine mechanical repairs, electrical system diagnostics, and bodywork adjustments. Suitable for professional technicians and advanced DIY enthusiasts.
Wrx Engine:
2.5L (2457cc) EJ255 flat-four, turbocharged, intercooled.
Sti Engine:
2.5L (2457cc) EJ257 flat-four, turbocharged, intercooled, with AVCS (Active Valve Control System).
Wrx Horsepower:
265 hp @ 6000 rpm
Wrx Torque:
244 lb-ft @ 4000 rpm
Sti Horsepower:
305 hp @ 6000 rpm
Sti Torque:
290 lb-ft @ 4000 rpm
Injection Type:
Multi-point fuel injection (Sequential).
Fuel Requirement:
Premium Unleaded (91 octane or higher recommended).
Radiator Capacity:
Approx. 7.4 US quarts (7.0 L).
Oil Capacity W Filter:
5.8 US quarts (5.5 L).
Recommended Oil Viscosity:
5W-30 (check manual for climate variations).
Wrx Transmission:
5-speed Manual (TY756).
Sti Transmission:
6-speed Manual (TY856).
Availability:
No automatic transmission offered for WRX or WRX STI in 2011.
Sti Dccd:
Driver Controlled Center Differential with Auto mode for variable torque distribution.
Differential Type:
Symmetrical All-Wheel Drive with front helical LSD, rear viscous LSD (WRX); Front helical LSD, rear mechanical LSD with DCCD (STI).
Manual Transmission Fluid Type:
GL-5 75W-90 Synthetic (check manual for specific Subaru-branded or approved fluids).
Manual Transmission Capacity:
Approx. 2.4 US quarts (2.3 L).
NHTSA Front Crash Test:
5-Star (for 2011 Impreza models overall).
IIHS Top Safety Pick:
Yes (for 2011 Impreza models overall).
Traction Control:
Yes (Subaru VDC - Vehicle Dynamics Control).
ABS:
Standard Anti-lock Braking System.
Ebd:
Standard Electronic Brake-force Distribution.
Airbags:
Front dual-stage airbags, front side-impact airbags, side-curtain airbags.
Seatbelts:
3-point height-adjustable front seatbelts with pretensioners and load limiters, rear 3-point seatbelts.
Chassis Design:
Ring-shaped reinforcement frame for enhanced crash protection.
Oil Change Interval:
Every 3,750 miles or 6 months, or 7,500 miles/12 months under severe driving conditions (check owner's manual for specifics).
Engine Air Filter:
Inspect every 15,000 miles, replace as needed.
Cabin Air Filter:
Inspect every 15,000 miles, replace as needed.
Spark Plugs:
Replace at 105,000 miles (Iridium type).
Coolant Replacement:
First replacement at 60,000 miles or 5 years, then every 30,000 miles or 2.5 years. (Subaru Super Coolant required).
Brake Fluid:
DOT 3 or DOT 4.
Power Steering Fluid:
Subaru Genuine ATF-HP or equivalent Dexron III/Mercon compatible fluid (check manual for exact specification).
Engine Ring Land Failure:
Prevalent issue in EJ25 engines, particularly with aggressive tuning or detonation. The manual will detail proper maintenance and diagnostics.
Clutch Wear:
Can be accelerated with aggressive driving, as expected for performance models. Manual will cover clutch inspection and replacement procedures.
Turbocharger Maintenance:
Proper warm-up and cool-down procedures are critical. Manual will cover turbocharger checks and potential issues.
Subaru Rally Heritage:
Subaru's long and successful history in the World Rally Championship (WRC) directly influences the engineering and design of the WRX and STI models.
Third Generation:
The 2011 model is part of the third generation (GE/GH/GR/GV) Impreza, which introduced more distinct styling and chassis improvements.
Wrx Vs Sti Distinction:
The STI historically represents the pinnacle of Impreza performance, featuring more advanced mechanicals and higher output compared to the standard WRX.
Manufacturing Location:
Japan
