Positioning:
The Subaru Impreza WRX STi is a performance-oriented compact car that competes in the enthusiast segment, known for its all-wheel-drive system, turbocharged engine, and rally-inspired heritage.
Competitors:
Mitsubishi Lancer Evolution, Volkswagen Golf GTI, Ford Focus RS, Mazdaspeed3.
Performance Focus:
This manual caters to owners and technicians who value the high-performance nature of the WRX STi and require detailed information for its upkeep and modification.
Diy Support:
Explicitly designed for both experienced DIY mechanics and professional technicians, offering comprehensive guidance.
Value:
Provides access to factory-level repair procedures and specifications, enabling owners to maintain or repair their WRX STi to original standards.
Powertrain:
Engine, fuel system, ignition system, exhaust system, transmission (manual and automatic options), drivetrain (AWD system, differentials, drive shafts).
Chassis:
Suspension (front and rear, including STi specific components), steering, brakes (including ABS and performance brake systems), wheels and tires.
Electrical:
Starting and charging system, lighting, instrumentation, power accessories, body control modules, engine control module (ECM), transmission control module (TCM), infotainment systems, wiring diagrams.
Body:
Exterior body panels, interior trim, climate control system, safety restraint systems (airbags), glass and mirrors.
Maintenance:
Scheduled maintenance, fluid checks and changes, filter replacements, lubrication points.
Diagnostics:
Troubleshooting guides, symptom-based diagnostics, fault code interpretation (OBD-II), component testing procedures.
Repair:
Detailed step-by-step repair instructions for all major vehicle systems, including engine overhauls, transmission rebuilds, brake caliper replacement, suspension component replacement, electrical component repair.
Assembly Disassembly:
Comprehensive instructions for component removal and installation.
Depth:
Comprehensive, covering everything from basic fluid changes to complete engine and transmission rebuilds, including detailed diagnostic procedures and wiring schematics.
Searchability:
Text-searchable PDF for efficient information retrieval.
Readability:
High-resolution scans of original factory documentation, ensuring clear text and diagrams.
Quality:
Designed for clear printing of all sections, including complex diagrams.
Type:
N/A (Digital Download)
Type:
N/A (Digital Download)
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
Valve Train:
DOHC, 16 valves, Variable Valve Timing (VVT).
Horsepower:
305 hp @ 6000 rpm (approx.)
Torque:
290 lb-ft @ 4000 rpm (approx.)
Injection Type:
Multi-point Fuel Injection (MPI) with Electronic Throttle Control (ETC).
Fuel Requirement:
Premium Unleaded Gasoline (91+ Octane Recommended)
Turbo Model:
IHI VF48 (or similar twin-scroll design)
Intercooler:
Top-mounted air-to-air intercooler.
Transmission Type:
6-speed Manual Transmission (STi specific)
Transmission Type:
N/A (STi models were exclusively manual for this generation)
AWD System:
Symmetrical All-Wheel Drive (AWD) with Driver Controlled Center Differential (DCCD) and Helical Limited Slip Front Differential (LSD) and Torsen Limited Slip Rear Differential.
Manual Transmission Fluid:
Subaru Genuine Gear Oil API GL-5, SAE 75W-90 (or equivalent)
Manual Transmission Capacity:
Approx. 3.5 Liters (3.7 US Quarts)
Length Hatchback:
4415 mm (173.8 inches)
Length Sedan:
4580 mm (180.3 inches)
Width:
1800 mm (70.9 inches)
Height Hatchback:
1475 mm (58.1 inches)
Height Sedan:
1475 mm (58.1 inches)
Wheelbase:
2625 mm (103.3 inches)
Curb Weight:
1505 kg (3318 lbs) - Hatchback (approx.)
Gross Vehicle Weight Rating:
Approx. 1950 kg (4299 lbs)
Wheel Size:
18 x 8.5 inches (standard)
Bolt Pattern:
5x114.3 mm (5x4.5 inches)
Tire Size Standard:
245/40R18 (standard)
NHTSA Front Crash:
5 Stars
NHTSA Side Crash:
5 Stars
IIHS Frontal Offset:
Good
Traction Control:
Yes (with Subaru Vehicle Dynamics Control - VDC)
Electronic Stability Control:
Yes (VDC)
ABS:
Yes, 4-wheel disc with Electronic Brake-force Distribution (EBD) and Brake Assist.
Airbags:
Front dual-stage, front side-impact, side-curtain (front and rear), driver's knee airbag.
Seatbelts:
3-point with pretensioners and load limiters, LATCH child seat anchors.
Head Unit:
Standard AM/FM/CD audio system, optional premium audio with subwoofer, Bluetooth connectivity (depending on trim and options).
Navigation:
Optional factory navigation system available on higher trims.
Cruise Control:
Standard cruise control.
Keyless Entry:
Standard keyless entry and ignition.
Bluetooth:
Available for hands-free calling and audio streaming.
Oil Change Interval:
Every 3,750 miles or 6 months (severe driving conditions), or 7,500 miles / 12 months (normal driving conditions), using synthetic oil.
Air Filter Replacement:
Every 15,000 - 30,000 miles or as needed based on conditions.
Spark Plug Replacement:
Every 60,000 - 105,000 miles (depending on plug type, iridium recommended).
Coolant Flush:
Every 30,000 miles or 2 years (using Subaru Super Coolant).
Engine Oil Spec:
SAE 5W-30 Synthetic (API SG, SH, SJ, SL, SM or SN)
Engine Oil Capacity:
Approx. 5.8 US Quarts (5.5 Liters) with filter.
Coolant Type:
Subaru Super Coolant (Blue) or equivalent Long Life (50/50 mix with distilled water).
Brake Fluid Spec:
DOT 3 or DOT 4.
Engine:
Potential for ringland failure or piston damage under extreme detonation (tuning related), turbo oil starvation if maintenance is neglected, valve seal leaks leading to oil consumption.
Transmission:
Clutch wear (especially with aggressive driving), potential for synchro issues in older transmissions, DCCD system quirks.
Suspension:
Premature wear of bushings and ball joints due to performance driving, potential for wheel bearing noise.
Electrical:
Infrequent issues with power window regulators, occasional sensor failures (e.g., camshaft position sensor).
Tip 1:
Regularly check and maintain the PCV system and breather hoses to prevent crankcase pressure issues.
Tip 2:
Use high-quality oil filters and ensure proper oil viscosity for the operating temperature.
Tip 3:
Monitor oil and coolant levels diligently, especially if the vehicle is driven hard.
Heritage:
Subaru's heritage is deeply rooted in motorsport, particularly in the World Rally Championship (WRC), which directly influenced the development and tuning of the WRX STi.
Generation:
This model represents the 'Third Generation' (GD/GG chassis for earlier models, GR/GV for this specific iteration) of the Impreza WRX STi, with significant chassis and styling updates.
Manufacturing Plant:
Ota City, Gunma Prefecture, Japan.
Model Year Range Covered:
Specifically 2008, with potential overlap and shared components with 2009 and 2007 models.
Rally Heritage:
The WRX STi nameplate itself is a recognition of Subaru's success in world rally championships.
Performance Reviews:
Consistently praised by automotive journalists for its handling, acceleration, and AWD capabilities.
Owner Satisfaction:
Generally high among enthusiasts who value its performance characteristics.
