Positioning:
The 2011 Subaru Impreza WRX STI is positioned as a high-performance, rally-bred compact sports sedan, targeting enthusiasts seeking exceptional handling, turbocharged power, and all-weather capability.
Competitors:
Key competitors at the time included the Mitsubishi Lancer Evolution, Volkswagen Golf GTI, Ford Focus RS, and similar performance-oriented vehicles in the compact segment.
Distinguishing Features:
Symmetrical All-Wheel Drive, Driver's Control Center Differential (DCCD), SI-Drive system, potent turbocharged Boxer engine, performance-tuned suspension, aggressive styling, and a legacy of motorsport success.
Engine:
2.5L EJ257 Turbocharged Boxer Engine
Engine Management:
ECU diagnostics, fuel injection, ignition system, emissions control
Transmission:
6-speed Manual Transmission (TY757)
Drivetrain:
All-Wheel Drive (Symmetrical AWD) system, differentials (front, center, rear), driveshafts
Suspension:
Front strut type, rear multi-link, springs, dampers, anti-roll bars
Brakes:
Front Brembo 4-piston calipers, Rear Brembo 2-piston calipers, ABS, EBD, brake fluid specifications
Steering:
Hydraulic power steering system
Electrical System:
Battery, alternator, starter, lighting, wiring diagrams, fuse box locations, relays
Climate Control:
HVAC system, A/C refrigerant, heater core, blower motor
Body And Chassis:
Body panels, doors, hood, trunk, interior trim, chassis components, chassis reinforcement
Safety Systems:
Airbag system, seatbelts, SRS components
Maintenance:
Scheduled maintenance, oil changes, filter replacements, fluid checks and top-offs, spark plug replacement, belt inspection
Troubleshooting:
Diagnostic procedures, fault codes, symptom analysis for all major systems
Repair:
Component removal and installation, engine overhaul, transmission rebuild, suspension component replacement, brake caliper rebuild, electrical component repair
Diagnostics:
Detailed diagnostic flowcharts, component testing procedures, use of Subaru Select Monitor (SSM) or equivalent tools
Calibration:
Alignment procedures, steering angle sensor calibration, other necessary system calibrations
Depth:
Expert level, suitable for professional technicians and advanced DIY enthusiasts. Includes detailed specifications, torque values, special tool requirements, and step-by-step instructions.
Engine Type:
2.5-liter turbocharged, horizontally opposed (Boxer) 4-cylinder
Bore X Stroke:
99.5 mm x 79.0 mm
Valve Train:
DOHC, 16 valves, AVCS (Active Valve Control System)
Horsepower Hp:
305 hp @ 6000 rpm
Torque Lb-Ft:
290 lb-ft @ 4000 rpm
Fuel Type:
Premium Unleaded Gasoline (91 octane or higher recommended)
Fuel Delivery:
Multi-point fuel injection, Turbocharged by a twin-scroll IHI VF48 turbocharger
NHTSA Front Impact:
5-Star
NHTSA Side Impact:
5-Star
IIHS Frontal Offset:
Good
ABS:
Standard Anti-lock Braking System
Ebd:
Standard Electronic Brake-force Distribution
Vcs:
Standard Vehicle Stability Control
TCS:
Standard Traction Control System
Airbags:
Driver and front passenger airbags, front side-impact airbags, side curtain airbags
Seatbelts:
3-point front and rear seatbelts with pretensioners and load limiters
Audio System:
Standard AM/FM/CD stereo with auxiliary input and SiriusXM Satellite Radio capability. Optional upgraded Boston Acoustics audio system.
Navigation:
Optional factory-installed GPS navigation system.
Si Drive:
Subaru Intelligent Drive (SI-DRIVE) system offering three distinct engine and drivetrain response modes: Intelligent (I), Sport (S), and Sport Sharp (S#).
Bluetooth:
Available Bluetooth hands-free phone connectivity and audio streaming on equipped models.
Oil Change Interval:
Typically every 3,750 miles or 3.75 months for severe driving, or 7,500 miles or 7.5 months for normal driving (refer to owner's manual for specifics).
Engine Oil Type:
Synthetic SAE 0W-30 or 5W-30 (meeting API SN or ILSAC GF-5)
Engine Oil Capacity:
5.8 US quarts (5.5 liters) with filter change
Coolant Type:
Subaru Super Coolant (Blue) or equivalent silicate-free, long-life coolant
Brake Fluid:
DOT 3 or DOT 4 brake fluid
Transmission Fluid Type:
API GL-5, SAE 75W-90 (Synthetic recommended for STI)
Differential Fluid Type:
API GL-5, SAE 75W-90 (Synthetic recommended for STI)
Head Gaskets:
While less common on EJ257 compared to earlier EJ25 engines, head gasket integrity is a point of vigilance. Regular coolant checks and proper engine operating temperatures are crucial.
Piston Ringland Failure:
Can occur in high-performance applications due to detonation or improper tuning. The manual details engine inspection and repair procedures to mitigate this.
Clutch Wear:
As with any performance manual transmission, aggressive driving can lead to accelerated clutch wear. The manual provides clutch inspection and replacement procedures.
Turbocharger Wear:
Regular oil changes with quality oil are critical for turbocharger longevity. The manual covers turbocharger inspection and replacement.
