Positioning:
The 2004 Subaru Impreza WRX STI (GDB) represented the pinnacle of Subaru's rally-bred performance and homologation specials for the compact car segment, directly competing with vehicles like the Mitsubishi Lancer Evolution.
Competitors:
Mitsubishi Lancer Evolution VII/VIII, Honda Civic Type R (EP3 - though different class/powertrain), Ford Focus RS Mk1.
Performance Enhancements:
Larger EJ207 engine, twin-scroll turbocharger, DCCD, reinforced chassis, larger brakes, specific STI suspension tuning, aggressive aerodynamic body kit.
Rally Heritage:
Designed with World Rally Championship (WRC) homologation in mind, sharing many characteristics with Subaru's successful WRC cars.
Engine:
EJ207 (2.0L DOHC Turbocharged Boxer), including timing, lubrication, cooling, fuel injection, ignition, emissions, and turbocharger systems.
Transmission:
6-speed manual transmission (TY757), including clutch, driveline, and AWD system (Driver Controlled Centre Differential - DCCD).
Suspension And Steering:
Front MacPherson struts, rear multi-link suspension, power steering system.
Brakes:
Front and rear disc brakes (including potential Brembo caliper specifics if applicable to 2004 STI), ABS system.
Electrical System:
Wiring diagrams, fuses, relays, battery, charging system, lighting, instruments, ECUs, body control modules.
Body And Chassis:
Body panels, interior trim, glass, structural components, corrosion protection.
HVAC:
Heating, ventilation, and air conditioning systems.
Maintenance:
Oil changes, filter replacements, fluid checks and top-offs, spark plug replacement, belt inspections.
Repair:
Engine component rebuilds (pistons, rods, bearings), turbocharger service, transmission overhaul, suspension component replacement, brake caliper/rotor service, electrical component diagnosis and repair.
Diagnostics:
Troubleshooting guides, diagnostic trouble codes (DTCs), symptom-based diagnostics.
Installation:
Component replacement procedures, accessory installation guidelines.
Depth:
Comprehensive: Covers basic maintenance to complete engine and transmission rebuilds, including detailed diagnostic procedures and specifications.
Engine Type:
Horizontally Opposed (Boxer), 4-Cylinder, DOHC, 16-Valve
Displacement:
1994 cc (2.0 Liters)
Bore X Stroke:
92.0 mm x 75.0 mm
Horsepower:
265 PS (approx. 261 hp) @ 6000 rpm (JDM specification, may vary slightly for export markets)
Torque:
343 Nm (approx. 253 lb-ft) @ 4000 rpm (JDM specification, may vary slightly for export markets)
Fuel Delivery:
Multi-point fuel injection (MPI)
Turbocharger:
IHI VF37 (Twin-scroll)
Fuel Type:
Premium Unleaded Gasoline (95 RON or higher)
NHTSA Crash Tests:
Specific NHTSA ratings for 2004 STI are not widely publicized or may vary by market; later GD chassis models received varying ratings.
Traction Control:
Standard Subaru All-Wheel Drive with DCCD, ABS.
Brake Assist:
Likely included with ABS depending on market.
Airbags:
Front airbags (driver and passenger), potential side airbags depending on market/trim.
Seatbelts:
Pre-tensioner seatbelts
Chassis Reinforcement:
Enhanced chassis rigidity for rally performance.
Head Unit:
Factory fitted radio/CD player; often upgraded by owners for modern features.
Gauges:
Performance-oriented instrument cluster including boost gauge and DCCD indicator.
ABS:
Anti-lock Braking System (ABS) standard.
AWD System:
Subaru's Symmetrical All-Wheel Drive with Driver Controlled Centre Differential (DCCD) offering manual and automatic locking modes.
Original Connectivity:
Basic; no integrated Bluetooth or USB ports in the factory system.
Oil Change Interval:
Every 3,750 miles (6,000 km) or 3 months, whichever comes first (severe driving conditions often recommended for performance vehicles).
Timing Belt Interval:
Every 60,000 miles (96,000 km) or 4 years (critical for EJ series engines).
Engine Oil:
Subaru recommends 5W-30 or 10W-30 synthetic oil. Refer to manual for exact API service classification (e.g., API SN or newer).
Coolant:
Subaru Super Coolant (Blue) or equivalent ethylene glycol-based coolant with corrosion inhibitors. Mixture of 50/50 with distilled water.
Transmission Fluid:
Subaru Extra-S Gear Oil (Hypoid Gear Oil, GL-5) for 6-speed transmission. Capacity approx. 3.4 L (3.6 US qt).
Differential Fluid Front:
Hypoid Gear Oil, GL-5 (API classification). Capacity approx. 1.0 L (1.1 US qt).
Differential Fluid Rear:
Hypoid Gear Oil, GL-5 (API classification). Capacity approx. 1.1 L (1.2 US qt).
Brake Fluid:
DOT 3 or DOT 4 brake fluid.
Piston Ring Land Cracking:
A known issue with early EJ207 engines in some conditions, particularly with aggressive tuning or sustained high-end use. The manual would detail proper piston inspection and replacement procedures.
Clutch Wear:
Performance driving can lead to accelerated clutch wear. The manual details clutch inspection, replacement, and proper bleeding procedures.
Turbo Failure:
Oil starvation or contamination can lead to turbo failure. Proper maintenance, oil changes, and cool-down periods are crucial. Manual provides turbocharger diagnosis and repair.
Suspension Bushings:
Wear on suspension bushings can affect handling. Manual covers inspection and replacement of all suspension components and bushings.
Brand Focus:
Subaru has a strong heritage in motorsport, particularly in rallying, which significantly influences the Impreza STI's design and engineering.
Generation:
Second Generation (GDB) Impreza, specifically the STI variant.
2004 Updates:
The 2004 model year marked a significant update for the GDB chassis, often referred to as the 'Hawkeye' or 'Blobeye' refresh depending on regional classification, introducing revised styling and mechanical enhancements.
Production Location:
Gunma Plant, Japan
