Vehicle Segment:
Performance Compact Sedan/Hatchback (All-Wheel Drive)
Competitors:
Mitsubishi Lancer Evolution, Subaru WRX (non-STI variants), Mitsubishi Eclipse GT, Nissan Sentra SE-R, Volkswagen GTI
Key Selling Points:
Symmetrical All-Wheel Drive, turbocharged boxer engine, rally-bred heritage, performance tuning potential, driver-focused chassis dynamics
Manual Value Proposition:
Provides factory-level diagnostic and repair information, empowering owners and technicians to maintain and restore the vehicle to original specifications. Offers comprehensive coverage not found in generic repair guides.
Manual Uniqueness:
Factory-sourced data ensures accuracy and completeness for specialized performance systems unique to the WRX STI model.
Powertrain:
Engine mechanical, engine management, fuel system, exhaust system, cooling system, lubrication system, transmission (manual & automatic), drivetrain (AWD system)
Chassis:
Suspension (front & rear), steering system, braking system (ABS, EBD), wheel alignment
Electrical:
Wiring diagrams, charging system, starting system, lighting system, instruments and indicators, body electrical, power accessories, audio system, safety systems (airbags, immobilizer)
Body And Trim:
Exterior body panels, interior trim, doors, windows, seats, HVAC system (climate control)
Diagnostics And Troubleshooting:
Diagnostic trouble codes (DTCs), symptom-based troubleshooting, component testing, electrical diagnostics
Maintenance:
Scheduled maintenance, oil changes, filter replacements, fluid checks and changes, belt and hose inspection/replacement
Repair:
Engine rebuild procedures, transmission overhaul, brake caliper replacement, suspension component replacement, electrical component repair/replacement, body panel repair
Diagnostics:
Fault finding, system checks, measurement of electrical signals, pressure testing
Adjustment And Calibration:
Wheel alignment, throttle body cleaning/calibration, idle speed adjustment (where applicable)
Depth Of Coverage:
Comprehensive: covers basic maintenance to complete engine and transmission rebuilds, detailed diagnostic procedures, and electrical system troubleshooting.
Target Audience:
Professional technicians, experienced DIY enthusiasts
Engine Type:
Horizontally-opposed (Boxer) 4-cylinder, turbocharged and intercooled
Displacement:
2.5 Liters (2457 cc)
Bore X Stroke:
99.5 mm x 79.0 mm
Valvetrain:
DOHC, 4 valves per cylinder, AVCS (Active Valve Control System)
Horsepower:
305 hp @ 6000 rpm (U.S. Market)
Torque:
290 lb-ft @ 4000 rpm (U.S. Market)
Fuel Type:
Premium Unleaded Gasoline (91 AKI or higher recommended)
Fuel Delivery:
Multi-point Fuel Injection (MPI)
Turbocharger:
IHI VF48 Twin-Scroll Turbocharger
Transmission Type:
6-speed Manual Transmission (TY757)
Transmission Type:
None for WRX STI in this generation
Drivetrain:
Symmetrical All-Wheel Drive (SAWD) with Driver Controlled Center Differential (DCCD)
Differential Type:
Front: Helical limited-slip; Rear: Viscous limited-slip
Clutch Type:
Hydraulically actuated, single dry plate
Length:
179.3 inches (4555 mm) (Hatchback - GR), 179.5 inches (4560 mm) (Sedan - GV)
Width:
70.7 inches (1795 mm)
Height:
57.9 inches (1470 mm) (Hatchback - GR), 57.1 inches (1450 mm) (Sedan - GV)
Wheelbase:
103.0 inches (2615 mm)
Front Track:
60.2 inches (1530 mm)
Rear Track:
59.8 inches (1520 mm)
Curb Weight:
Approximately 3375 - 3417 lbs (1530 - 1550 kg) depending on body style
Gross Vehicle Weight Rating:
4564 lbs (2070 kg)
NHTSA Overall:
Not specifically rated for STI, but Impreza models received 5-star ratings in some tests.
IIHS Front Crash:
Good (for Impreza)
ABS:
Anti-lock Braking System with Electronic Brake-force Distribution (EBD)
Traction Control:
Vehicle Dynamics Control (VDC)
AWD System:
Driver Controlled Center Differential (DCCD) for active torque distribution
Airbags:
Front airbags, front side-impact airbags, curtain side airbags
Seatbelts:
3-point ELR front and rear seatbelts with pre-tensioners and force limiters
Child Anchors:
LATCH (Lower Anchors and Tethers for CHildren) system
Head Unit:
Standard AM/FM/CD player with auxiliary input, optional navigation system available.
Audio System:
Optional premium audio system with subwoofer.
Cruise Control:
Standard cruise control
Keyless Entry:
Standard keyless entry with remote locking/unlocking.
Usb Port:
Not standard on all models, some later variants may have auxiliary input.
Oil Change Interval:
Every 3,750 miles or 3 months (severe driving), 7,500 miles or 6 months (normal driving) - consult manual for specifics.
Major Service Intervals:
Timing belt replacement (if applicable, consult specific engine variant), spark plug replacement (e.g., 60,000 miles), brake fluid flush (e.g., 30,000 miles or 2 years).
Engine Oil:
SAE 5W-30, API SN or higher, ILSAC GF-5 or higher (synthetic recommended, e.g., Mobil 1 5W-30)
Transmission Fluid:
Subaru Extra-S Gear Oil (75W-90) or equivalent API GL-5 synthetic
Differential Fluid Front:
API GL-5 (75W-90) or equivalent
Differential Fluid Rear:
API GL-5 (75W-90) or equivalent
Coolant:
Subaru Super Coolant (Blue) or equivalent ethylene glycol-based antifreeze/coolant (50/50 mix)
Brake Fluid:
DOT 3 or DOT 4 brake fluid
Engine Related:
Head gasket failures (less common on EJ257 than earlier versions, but possible), piston ring land failures, turbocharger wear/failure, oil consumption.
Drivetrain Related:
Clutch wear, DCCD system issues (rare).
Suspension Related:
Rattles or clunks from strut mounts, premature wear of bushings.
Engine Break In:
Proper break-in procedures are critical for turbocharged engines; avoid hard acceleration and high RPMs during the initial 1,000 miles.
Performance Maintenance:
Regular inspection and replacement of air filters, spark plugs, and coolant are vital for maintaining optimal performance of the EJ257 engine.
Motorsport Roots:
Subaru's extensive success in the World Rally Championship (WRC) heavily influenced the development of the WRX and WRX STI models, establishing their performance credentials.
Previous Generation:
Second Generation (GD/GG) Impreza WRX STI
Key Changes 2008-2011:
Introduction of the 'wide-body' chassis for better handling and stability, revised aerodynamics, upgraded DCCD system, and increased engine power.
Body Styles:
Available as a 5-door hatchback (GR) and a 4-door sedan (GV).
Manufacturing Location:
Ōta, Gunma, Japan
Car And Driver 10Best:
Subaru WRX models (including STI variants) were frequently recognized on Car and Driver's 10Best lists for their performance and value.
Sport Compact Car Of The Year:
The WRX STI has historically received numerous awards and accolades from automotive publications in the performance compact segment.
Emissions Certification:
Meets EPA and CARB emissions standards for the model year.
