Model Code:
GC8, GDB, GRB, GVB
Production Years Covered:
1993-2015
Chassis Codes:
GC8, GC6, GC4, GF8, GM6, GD2, GDA, GDB, GRB, GVB
Engine Codes:
EJ20G, EJ20K, EJ207, EJ205, EJ255, EJ257, EJ25D (naturally aspirated variations also included for context)
Market Position:
The Subaru Impreza WRX STI represents a halo model for Subaru, positioned as a performance-oriented, all-wheel-drive compact sports sedan/hatchback, a key player in the affordable performance car segment.
Competitive Analysis:
Competes with vehicles such as Mitsubishi Lancer Evolution, Ford Focus RS, Volkswagen Golf GTI/R, Honda Civic Type R, and various other hot hatches and performance sedans. Its signature symmetrical all-wheel-drive and turbocharged boxer engine are key differentiators.
Key Features:
Symmetrical All-Wheel Drive (SAWD), turbocharged Boxer engine, performance-tuned suspension, advanced driver-controlled center differential (DCCD), rally-bred DNA, strong aftermarket support.
Performance Focus:
The WRX STI is designed for spirited driving, emphasizing acceleration, braking, and handling on diverse road surfaces, drawing heavily from its WRC heritage.
Coverage Areas:
North America, Europe, Japan, Australia
Page Count:
Estimated 7000+ pages (comprehensive compilation)
Manual Type:
Workshop Service Repair Manual
Format:
Digital Download (PDF)
Systems Covered:
Engine Mechanical, Engine Control (ECU), Fuel System, Ignition System, Exhaust System, Cooling System, Lubrication System, Intake System, Turbocharging System, Transmission (Manual & Automatic), Drivetrain (All-Wheel Drive System), Suspension (Front & Rear), Steering System, Braking System (ABS, VDC), Electrical System (Wiring Diagrams, ECUs, Components), Climate Control System, Body & Chassis, Interior Trim, Exterior Panels, Safety Systems (Airbags, Seatbelts), Diagnostics & Troubleshooting
Procedures Included:
Routine Maintenance, Scheduled Servicing, Engine Overhaul, Transmission Rebuild, Differential Service, Suspension Component Replacement, Brake Caliper Rebuild, ABS/VDC System Diagnosis, Electrical Component Testing, Turbocharger Maintenance and Replacement, ECU Flashing and Programming, Body Panel Repair and Alignment, Interior Component Removal and Installation, Diagnostic Trouble Code (DTC) Procedures, Wiring Harness Repair
Technical Depth:
Comprehensive; covers basic maintenance to full engine and drivetrain rebuilds, including advanced diagnostic procedures and wiring schematics.
Diagnostics Coverage:
Detailed diagnostic procedures for engine management, ABS, VDC, airbag systems, and other electronic modules. Includes diagnostic trouble codes (DTCs), their meanings, and troubleshooting flowcharts. Access to On-Board Diagnostics (OBD-II) data interpretation.
Body Chassis Coverage:
Detailed information on chassis construction, body panel removal/installation, door mechanisms, glass replacement, rust prevention, and collision repair procedures.
File Format:
PDF, Searchable Text, Bookmarked Chapters
Print Quality:
High Resolution Illustrations, Photos, and Diagrams
Binding Type:
N/A (Digital Download)
Paper Type:
N/A (Digital Download)
Completeness:
Extremely comprehensive, covering all aspects of vehicle maintenance, repair, and diagnostics across the specified model years and variants. Includes factory service procedures and specifications.
Usability:
Organized into logical sections, with a comprehensive index and search functionality within the digital format for quick access to specific repair or diagnostic information.
Primary Engine:
2.0L and 2.5L Turbocharged Subaru Boxer (EJ series)
Horsepower Range:
207 hp to 305 hp (depending on year and market)
Torque Range:
250 lb-ft to 393 lb-ft (depending on year and market)
Fuel Injection:
Multi-Point Fuel Injection (MPFI) and Sequential Multi-Port Fuel Injection (S-MPFI)
Fuel Type:
Premium Unleaded Gasoline (91 octane or higher recommended)
Turbocharger Details:
Water-cooled, twin-scroll or single-scroll turbochargers (e.g., IHI VF series) with intercoolers.
Engine Layout:
Horizontally-opposed (Boxer) 4-cylinder
Engine Control System:
Subaru Engine Control Unit (ECU) with sophisticated fuel, ignition, and boost control strategies. ECU tuning and flashing procedures are often detailed.
Standard Transmission:
5-speed and 6-speed Manual Transmissions
Optional Transmission:
4-speed Automatic Transmission (less common on STI models)
Dccd:
Driver-Controlled Center Differential (manual transmission models), allowing manual adjustment of front/rear torque split.
Drivetrain:
Symmetrical All-Wheel Drive (SAWD) with various configurations including viscous coupling, Torsen limited-slip center differential, and Driver-Controlled Center Differential (DCCD).
NHTSA Ratings General:
Varies by year and testing methodology; generally good for its era, with later models achieving higher scores. Specific ratings require year-by-year lookup.
IIHS Ratings General:
Varies by year and testing methodology. Some generations received 'Good' or 'Acceptable' ratings.
Active Features:
Symmetrical All-Wheel Drive, Anti-lock Braking System (ABS), Electronic Brake-force Distribution (EBD), Traction Control System (TCS), Vehicle Dynamics Control (VDC - later models), Brembo performance brakes (STI models)
Passive Features:
Front Airbags, Side Airbags, Curtain Airbags (later models), Three-Point Seatbelts with pretensioners, High-Strength Steel Body Structure.
Brake System:
Front: Ventilated Discs, Rear: Solid or Ventilated Discs. STI models feature Brembo calipers.
Infotainment Systems:
Base stereo systems with CD players in early models; upgraded infotainment systems with touchscreens, navigation, Bluetooth, and smartphone integration in later generations (e.g., Subaru Starlink).
Driver Assistance Features:
Limited in early models; later generations offered features like rearview cameras, adaptive cruise control, Subaru EyeSight driver assist technology (on select trims/years).
Connectivity Options:
Auxiliary input jacks, USB ports, Bluetooth hands-free calling and audio streaming in later models.
Instrumentation Features:
Multi-function displays, boost gauges (STI), gear shift indicators, advanced driver information systems in later models.
Oil Change Interval:
Typically every 3,750 to 7,500 miles (6,000 to 12,000 km) or 6-12 months, depending on driving conditions and oil type. Consult manual for specific recommendations.
Timing Belt Replacement Interval:
For models with timing belts (EJ20G, EJ20K, EJ25D), typically every 60,000 miles (96,000 km) or 5 years. Later models with timing chains have different maintenance requirements.
Engine Oil Specification:
SAE 5W-30, 10W-30, or 10W-40 synthetic or semi-synthetic oil. Refer to owner's manual for specific viscosity based on climate.
Coolant Specification:
Subaru Super Coolant (Blue) or equivalent ethylene glycol-based coolant with Subaru anti-corrosion additives.
Transmission Fluid Specification Manual:
API GL-5, SAE 75W-90 synthetic gear oil. Specifics vary by transmission type (e.g., STI 6-speed).
Transmission Fluid Specification Automatic:
Subaru ATF-HP or equivalent.
Differential Fluid Specification:
API GL-5, SAE 75W-90 or 75W-140 synthetic gear oil for front and rear differentials. Center differential fluid requirements vary by DCCD type.
Known Issues:
Head gasket failures (pre-2005 models), piston ring land failures (ringland fatigue), turbocharger failures, clutch wear, differential issues (especially in high-performance driving), spark plug blowouts, catalytic converter failures.
Oil Filter Example Part Number:
Subaru 15208AA031 (Note: Part numbers vary by year and engine; manual will provide definitive lists).
Air Filter Example Part Number:
Subaru 16546AA050 (Note: Part numbers vary by year and engine; manual will provide definitive lists).
Engine Oil Capacity:
Approximately 4.8 US quarts (4.6 L) for 2.0L turbo, 5.1 US quarts (4.8 L) for 2.5L turbo. Consult manual for exact capacity and filter.
Coolant Capacity:
Approximately 7.5 US quarts (7.1 L). Refer to manual for specific capacities by model year and radiator size.
Brand Heritage:
Subaru's lineage in motorsport, particularly rallying with the Subaru World Rally Team (SWRT), heavily influenced the development and marketing of the WRX and WRX STI models. This rally pedigree is a core part of the brand's identity.
Model Evolution:
The Impreza WRX STI has evolved through several generations (GC8, GDB, GRB/GVB). Key changes include chassis updates, engine power increases, adoption of electronic driver aids, introduction of hatchback variants, and refinements in interior and exterior styling. Each generation has aimed to enhance performance and handling while maintaining its AWD identity.
Production Locations:
Primarily Japan (Gunma Plant), with some models for specific markets assembled or adapted elsewhere.
Model Variants:
WRX (tuned performance), WRX STI (higher performance, DCCD, Brembos, different engine tuning), WRX STI Type RA, S203, S204, S207, spec C, etc. (special editions).
