Market Position:
The Subaru Impreza STI (Subaru Tecnica International) is a high-performance, rally-bred compact sports sedan/hatchback known for its all-wheel-drive capabilities and turbocharged engine. It occupies a niche market segment for enthusiasts seeking a potent and engaging driving experience.
Key Competitors:
Mitsubishi Lancer Evolution, Volkswagen Golf GTI, Ford Focus RS (in later generations), Mazdaspeed3.
Key Features Of Vehicle:
Symmetrical All-Wheel Drive, turbocharged Boxer engine, performance-tuned suspension, aggressive styling, driver-focused interior.
Engine Systems:
Engine mechanical, lubrication, cooling, fuel injection, ignition, exhaust, emissions control, turbocharger system
Drivetrain Systems:
Manual transmission (TY75/TY85 series), all-wheel-drive system (DCCD), differentials (front, center, rear), clutch system
Chassis Systems:
Suspension (front struts, rear multi-link), steering system (power steering), braking system (ABS, EBD, brake calipers, rotors), wheel alignment
Electrical Systems:
Wiring diagrams, starting system, charging system, lighting, instruments, power accessories, fuse/relay locations, ECU diagnostics
Body And Interior:
Body panels, doors, windows, seats, HVAC system, interior trim, safety restraint system (airbags)
Maintenance Procedures:
Oil changes, filter replacements, spark plug replacement, air filter replacement, coolant flush, brake fluid service, differential fluid change
Repair Procedures:
Engine rebuild, transmission overhaul, brake caliper replacement, suspension component replacement, turbocharger service, clutch replacement, electrical component diagnosis and replacement
Troubleshooting Guides:
Diagnostic trouble codes (DTCs), symptom-based troubleshooting, common failure analysis
Technical Depth:
Comprehensive, covering routine maintenance, diagnostics, and complete mechanical and electrical repairs. Includes detailed component removal and installation procedures.
Engine Type:
2.5L Flat-Four (Horizontally Opposed) Turbocharged DOHC
Horsepower:
305 bhp @ 6000 rpm
Torque:
290 lb-ft @ 3500 rpm
Fuel Induction:
Sequential multi-port fuel injection (MPI) with Subaru's AVCS (Active Valve Control System)
Turbocharger:
IHI VF48 Twin-Scroll Turbocharger with intercooler
Bore X Stroke:
99.5 mm x 79.0 mm
Engine Oil Capacity:
4.8 US Quarts (with filter)
Recommended Oil Viscosity:
SAE 5W-30 (Full Synthetic)
Transmission Type:
6-Speed Manual (TY85)
Optional Transmission:
None for STI model
All Wheel Drive System:
Symmetrical All-Wheel Drive with Driver Controlled Center Differential (DCCD)
Center Differential Modes:
Automatic Mode, Manual Lock Mode (with 6 settings)
Manual Transmission Fluid Spec:
API GL-5, SAE 75W-90 (Subaru Extra-S or equivalent)
Rear Differential Fluid Spec:
API GL-5, SAE 75W-90 (Subaru Extra-S or equivalent)
Wheelbase:
103.2 inches (2620 mm)
Length:
173.8 inches (4415 mm) (Sedan) / 174.0 inches (4420 mm) (Hatchback)
Width:
70.1 inches (1780 mm)
Height:
57.7 inches (1465 mm) (Sedan) / 58.1 inches (1475 mm) (Hatchback)
Curb Weight:
Approx. 3373 lbs (1530 kg) (Sedan) / 3395 lbs (1540 kg) (Hatchback)
Gross Vehicle Weight Rating:
Approx. 4300 lbs (1950 kg)
Trunk Volume:
Approx. 11.6 cu ft (328 L) (Sedan) / 19.0 cu ft (538 L) with seats up (Hatchback)
Wheelbase Bolt Pattern:
5x114.3 mm (5x4.5 inches)
Standard Wheel Size:
18 x 8.5 inches
Standard Tire Size:
245/40R18
NHTSA Front Crash Test Rating:
5 Stars (for comparable models in this generation)
IIHS Moderate Overlap Front Rating:
Good (for comparable models in this generation)
Active Safety Features:
Anti-lock Braking System (ABS), Electronic Brake-force Distribution (EBD), Traction Control System (TCS), Vehicle Stability Control (VSC) with Sport Mode, Brembo performance brakes (front and rear)
Passive Safety Features:
Front dual-stage airbags, front side-impact airbags, curtain airbags (front and rear), front seatbelt pretensioners, crumple zones, high-strength steel body structure
Infotainment System:
Standard Subaru CD player with MP3 capability, AM/FM tuner, and auxiliary input jack. Optional dealer-installed upgrades or aftermarket head units were common.
Speaker System:
Typically 6-speaker system. Higher trims might have premium audio options.
Driver Assistance Features:
ABS, EBD, TCS, VSC. No advanced driver-assistance systems (ADAS) like adaptive cruise control or lane-keeping assist were standard on this model.
Connectivity Features:
Auxiliary audio input. Bluetooth connectivity was an optional dealer-installed accessory or found in aftermarket head units.
Oil Change Interval:
Every 3,750 miles or 3.75 months (severe conditions), or 7,500 miles or 7.5 months (normal conditions), but often recommended more frequently for STI models due to performance driving.
Engine Air Filter:
Inspect every 7,500 miles, replace as needed (often sooner with performance driving).
Cabin Air Filter:
Inspect every 7,500 miles, replace annually or as needed.
Spark Plugs:
Replace every 60,000 miles (iridium type).
Coolant Type:
Subaru Super Coolant (Blue) or equivalent silicate-free, long-life antifreeze/coolant.
Brake Fluid Spec:
DOT 3 or DOT 4
Power Steering Fluid Spec:
Subaru Genuine Power Steering Fluid or Dexron III ATF
Common Issues:
Head gasket failures (though less common on EJ257 than previous EJ25 variants), ringland failure in cylinders 3 and 4 under high boost/poor tuning, clutch wear due to performance driving, turbocharger wear/failure, attention to DCCD system maintenance.
Maintenance Importance:
Due to its performance nature, strict adherence to maintenance schedules and using quality fluids is crucial to prevent premature component failure.
Brand Rally Heritage:
Subaru's rich history in World Rally Championship (WRC), achieving multiple manufacturer and driver championships, directly influencing the STI's development and performance DNA.
Previous Generation Sti:
The 2008 STI represents the first generation of the Impreza STI to be officially sold in the United States, succeeding the more limited Subaru Impreza WRX STI (GD chassis) which was available in limited numbers previously.
Styling Change:
This generation (GE/GH/GR/GV) marked a significant departure from the previous 'bug-eye', 'blob-eye', and 'hawkeye' designs, adopting a more mainstream and less aggressive 'C-shaped' headlight design, though the STI retained its distinctive aerodynamic enhancements.
Production Location:
Gunma Plant, Japan
Performance Awards:
Consistently ranked highly by automotive publications for its performance, handling, and all-wheel-drive capabilities. Often featured in 'best performance car' lists within its price bracket.
Driving Enthusiast Ratings:
Praised for driver engagement, steering feel, and the effectiveness of its AWD system, particularly in challenging conditions.