🏷️ Basic Information Identification Make: Subaru Model: Impreza Year: 2006 Model Variant: WRX STI Codes Chassis Code: GDB Engine Code Primary: EJ257 Engine Code Secondary Non Sti: H4SO (likely naturally aspirated EJ253 or similar) Engine Code Turbo Variant: H4DOTC (indicating Turbocharged, likely EJ257 for STI) 👋 Introduction Market Position Positioning: Performance-oriented compact car with rally heritage, targeting enthusiasts and performance drivers. Competitive Analysis Competitors 2006: Mitsubishi Lancer Evolution, Honda Civic Si, Volkswagen GTI, Mazdaspeed3 Key Features Performance Focus: Legendary turbocharged EJ257 engine, Symmetrical All-Wheel Drive, performance-tuned suspension and chassis. Rally Heritage: Direct lineage from Subaru's World Rally Championship success. Manual Value Proposition Value For Owners: Essential for owners seeking to perform their own maintenance, diagnostics, and repairs, ensuring optimal performance and longevity of their STI. 📋 Manual Details Coverage Areas Main Areas: Engine (STI H4SO, H4DOTC Turbo), Transmission, Chassis, Body, Wiring Page Count Estimated Pages: 1500+ Manual Type Type: Factory Service Workshop Repair Manual Language Language: English Format Format: Digital (likely PDF) 📖 Manual Coverage Systems Covered Engine Systems: Engine mechanical (EJ257, EJ253 variants), lubrication, cooling, fuel delivery, ignition, emissions control, turbocharger system, exhaust, engine diagnostics, ECU tuning parameters (for STI) Transmission Systems: Manual transmission (TY757/TY758 for STI), clutch system, driveline, AWD system (VDC - Vehicle Dynamics Control) Chassis Systems: Suspension (front strut, rear multi-link), steering, brakes (ABS, EBD), wheel bearings, frame/unibody structure Body Systems: Body panels, doors, windows, interior trim, exterior trim, lighting, safety restraints (airbags, seatbelts) Electrical Systems: Wiring diagrams (comprehensive), starting and charging, lighting, instrumentation, HVAC controls, power accessories, ECU pinouts, sensor locations, diagnostic trouble codes (DTCs) Procedures Included Maintenance Procedures: Scheduled maintenance intervals, oil changes, filter replacements, fluid checks and changes, spark plug replacement, belt inspections/replacement Repair Procedures: Engine component removal/installation (pistons, connecting rods, crankshaft, cylinder heads, valve train), turbocharger overhaul, clutch replacement, transmission rebuild, suspension component replacement, brake caliper overhaul, body panel repair, interior component disassembly Diagnostic Procedures: Troubleshooting common problems, symptom-based diagnostics, wiring harness testing, sensor testing, ECU diagnostic procedures, use of Subaru Select Monitor (SSM) or equivalent diagnostic tools Special Procedures: Engine timing belt replacement (if applicable to the specific engine variant, though EJ257 typically uses a timing chain or has a robust belt system), turbocharger balancing, AWD system bleeding, VDC calibration Technical Depth Depth: Comprehensive: Covers everything from basic maintenance and diagnostics to complete engine rebuilds, transmission overhauls, and body/electrical system repairs. Includes torque specifications, clearances, and detailed schematics. 📊 Manual Specifications File Format Digital Format: PDF (Searchable, high-resolution scans of original factory documentation) Print Quality Scan Quality: High resolution, clear text and diagrams Binding Type Binding Type: N/A (Digital Format) Paper Type Paper Type: N/A (Digital Format) ⚙️ Engine Specifications Primary Engine Model: EJ257 (STI) Type: 2.5L (2457cc) DOHC 16-valve turbocharged flat-four (Boxer) Bore X Stroke: 99.5 mm x 79.0 mm Compression Ratio: 8.5:1 Horsepower Psi: 320 hp @ 6400 rpm (approx.) Torque Lb-Ft: 330 lb-ft @ 4000 rpm (approx.) Turbocharger: IHI VF39 (twin-scroll, intercooled) Fuel System: Sequential multi-port fuel injection (MPI), Denso 550cc fuel injectors Ignition System: Distributorless ignition system (DIS) with coil-on-plug ignition Engine Code Secondary Non Sti: H4SO (likely referring to naturally aspirated models like the 2.5i) - typically 2.5L EJ253, 165 hp, single-scroll turbo not applicable. Engine Code Turbo Variant: H4DOTC (referring to STI's turbocharged engine - EJ257) Performance 0 60 Mph Times: Approximately 4.4 seconds 🔧 Transmission Standard Type: 6-speed manual (TY757/TY758) Optional Type: N/A for STI (Manual only) Features Drivetrain: Symmetrical All-Wheel Drive with Driver Controlled Centre Differential (DCCD) Gear Ratios Sti: Refer to manual for specific ratios (e.g., 1st: 3.636, 2nd: 2.235, 3rd: 1.520, 4th: 1.121, 5th: 0.911, 6th: 0.719) Transmission Fluid Spec: API GL-5, SAE 75W-90 (Subaru Extra-S or equivalent) 📐 Dimensions Exterior Wheelbase: 103.5 inches (2630 mm) Length: 173.8 inches (4415 mm) Width: 69.7 inches (1770 mm) Height: 57.7 inches (1465 mm) Weights Curb Weight: 3370 lbs (1528 kg) approx. Gross Vehicle Weight Rating: Refer to manual/vehicle placard Towing Capacity: Not rated/Recommended not to tow 🛡️ Safety Features Ratings NHTSA Front Impact: 5-Star (2006 model year) IIHS Side Impact: Good (2006 model year, specific structure depends on tests) Active Features Brake Assist: Yes (BA) Electronic Stability: Yes (VDC - Vehicle Dynamics Control) Traction Control: Yes (TCS) Passive Features Airbags: Front, Side, Curtain Airbags Seatbelts: Pretensioner and load limiter equipped front seatbelts Child Anchors: LATCH system 💡 Technology Features Infotainment Audio System: AM/FM stereo with CD player, premium audio options may include subwoofer and amplifier. Driver Assistance ABS: Yes, with Electronic Brake-force Distribution (EBD) Vdc: Vehicle Dynamics Control (stability and traction control) Connectivity Bluetooth: N/A (Not standard on 2006 models) Aux Input: Likely available on higher trims or aftermarket installations. 🔧 Maintenance Service Intervals Oil Change Interval: Every 3,000-5,000 miles or 3-6 months (severe use may require more frequent changes, consult manual) Engine Oil Filter: Subaru OEM Part: 15208AA031 or equivalent Spark Plugs:...