🏷️ Basic Information

Make:

Subaru

Model:

Impreza WRX STI

Model Variant:

WRX STI

Model Generation:

Third Generation (GR/GV)

Production Years Covered:

2006-2007

Chassis Codes:

GDB (for sedan variant, which WRX STI typically represents)

👋 Introduction

Segment:

Performance Compact Sedan/Hatchback (depending on specific body style in 2006-2007)

Niche:

Rally-bred performance icon, known for its turbocharged boxer engine and Symmetrical All-Wheel Drive system.

Key Competitors:

Mitsubishi Lancer Evolution, Subaru WRX (non-STI variants), Ford Focus RS (in some markets)

Performance Focus:

Engineered for performance driving, track days, and spirited road use.

AWD System:

Symmetrical All-Wheel Drive with Driver's Control Center Differential (DCCD) for adjustable torque split.

Engine Technology:

High-output turbocharged EJ257 Boxer engine.

Manual Availability:

Essential resource for owners and independent technicians to maintain and repair this specialized vehicle.

📋 Manual Details

Overall Coverage:

Complete A-Z repair and maintenance for all models

Specific Models Covered:

All 2006-2007 Subaru Impreza WRX STI variants

Estimated Page Count:

Varies significantly by specific release, typically 1500+ pages for comprehensive factory service manuals

Type:

Factory Service Manual / Workshop Manual

Language:

English

Format:

Likely Digital (PDF), though original factory manuals were printed. Specific product may be a digital reproduction.

📖 Manual Coverage

Engine:

2.5L EJ257 Turbocharged Boxer Engine, including diagnostics, repair, and overhaul

Transmission:

6-speed manual transmission (TY856WL1CA), differentials (front, center DCCD, rear), clutch system

Drivetrain:

All-Wheel Drive system, including Driver's Control Center Differential (DCCD)

Suspension:

Front struts, rear shocks, control arms, sway bars, bushings, alignment specifications

Brakes:

Front and rear disc brakes, ABS system, brake fluid specifications, bleeding procedures

Steering:

Power steering system, steering rack, tie rods, alignment

Electrical:

Battery, charging system, ignition, lighting, starter, fuses, relays, body control modules, power windows, locks

Fuel System:

Fuel pump, injectors, fuel lines, fuel pressure regulator, emissions control

Cooling System:

Radiator, coolant, thermostat, water pump, fan operation

HVAC:

Air conditioning system, heater, climate control

Exhaust System:

Catalytic converter, mufflers, exhaust manifold, turbocharger integration

Body:

Exterior panels, interior trim, doors, hood, trunk, glass, seals

Safety Systems:

Airbags, seatbelts, ABS, SRS diagnostics

Maintenance:

Scheduled maintenance, oil changes, filter replacements, fluid checks and changes

Diagnostics:

Troubleshooting guides for all systems, fault code interpretation (OBD-II)

Repair:

Detailed step-by-step instructions for component removal, installation, and repair

Overhaul:

Engine and transmission rebuild procedures

Adjustments:

Engine tuning, suspension alignment, clutch adjustment

Installation:

Component replacement and installation guidance

Depth Of Information:

Comprehensive, covering basic maintenance to full engine and transmission overhauls. Designed for professional technicians.

Diagrams And Illustrations:

Includes detailed diagrams, exploded views, and wiring schematics

Special Tools:

Lists specific Subaru special tools required for certain procedures

📊 Manual Specifications

Digital Format Quality:

High-resolution scans or native digital files, typically searchable text within PDFs.

Print Quality:

N/A for digital formats; original printed manuals had professional print quality.

Binding Type:

N/A for digital formats; original printed manuals were typically perfect bound or spiral bound.

Paper Type:

N/A for digital formats; original printed manuals used durable, coated paper suitable for workshop environments.

⚙️ Engine Specifications

Engine Code:

EJ257

Configuration:

2.5L Flat-Four (Boxer), Turbocharged, Intercooled

Bore X Stroke:

99.5 mm x 79.0 mm

Compression Ratio:

8.2:1

Valvetrain:

DOHC, 16 valves (4 per cylinder), Subaru Variable Valve Lift and Timing (VVL/T)

Horsepower:

300 hp @ 6000 rpm (approximate)

Torque:

290 lb-ft @ 4000 rpm (approximate)

Fuel Delivery:

Sequential Multi-port Fuel Injection (MPI)

Fuel Type:

Premium Unleaded Gasoline (91 octane or higher recommended)

Turbocharger Model:

IHI VF39 (or similar variant for specific market)

Engine Oil Type:

SAE 5W-30 Synthetic (API SN or newer)

Engine Oil Capacity:

5.8 US quarts (5.5 liters) with filter change

Coolant Type:

Subaru Super Coolant (Blue) or equivalent silicate-free, long-life coolant

🔧 Transmission

Type:

6-speed Manual Transmission

Transmission Code:

TY856WL1CA (typical for this model)

Dccd:

Driver's Control Center Differential (DCCD) with automatic and manual modes for torque distribution.

Manual Transmission Fluid Type:

Subaru Extra-S Gear Oil (or equivalent API GL-5 75W-90)

Manual Transmission Fluid Capacity:

Approx. 3.2 US quarts (3.0 liters)

Rear Differential Fluid Type:

API GL-5 75W-90

Rear Differential Fluid Capacity:

Approx. 1.0 US quart (0.95 liters)

📐 Dimensions

Wheelbase:

103.1 inches (2619 mm)

Length:

173.8 inches (4415 mm)

Width:

69.1 inches (1755 mm)

Height:

57.7 inches (1466 mm)

Curb Weight:

3397 lbs (1541 kg) (approximate, depending on trim/body style)

Gross Vehicle Weight Rating Gvwr:

4500 lbs (2041 kg) (typical)

Standard Wheel Size:

17 x 8.0 inches (standard WRX), 18 x 8.5 inches (STI)

Standard Tire Size:

225/45R17 (standard WRX), 245/40R18 (STI)

Bolt Pattern:

5x114.3 mm (5x4.5 inches)

Offset:

ET55 (typical for 18-inch STI wheels)

🛡️ Safety Features

NHTSA Front Impact Rating:

5-star (for 2006 model year, typical for Subaru safety focus)

NHTSA Side Impact Rating:

4-star or 5-star (depending on specific configuration)

IIHS Front Crashworthiness:

Good

ABS:

Standard Anti-lock Braking System (4-wheel disc brakes)

Traction Control:

Yes, integrated with AWD and DCCD systems.

Electronic Stability Control:

Standard (Vehicle Dynamics Control - VDC)

Airbags:

Front dual-stage airbags, front side-impact airbags, side-curtain airbags (optional/standard depending on trim)

Seatbelts:

Pretensioner and load-limiter front seatbelts

Child Seat Anchors:

LATCH (Lower Anchors and Tethers for CHildren) system

💡 Technology Features

Audio System:

Factory AM/FM/CD player, possibly with premium audio options (e.g., Infinity).

Display Type:

Digital clock display, possibly basic LCD for audio information.

Cruise Control:

Standard electronic cruise control.

Dccd Control:

Manual control over the center differential torque split via a rotary dial.

Auxiliary Input:

Optional auxiliary audio input jack, depending on trim and audio system.

Type:

Manual or automatic climate control depending on trim level.

🔧 Maintenance

Oil Change Interval:

Every 3,750 miles or 6 months, or 7,500 miles/12 months for synthetic oil depending on driving conditions (refer to manual for specific recommendation).

Air Filter Replacement:

Every 15,000 miles or 12 months, or more frequently under dusty conditions.

Cabin Air Filter Replacement:

Every 15,000 miles or 12 months.

Spark Plug Replacement:

NGK Iridium spark plugs (e.g., PFR7B or similar) typically at 30,000-60,000 miles, depending on application and condition.

Timing Belt Replacement:

N/A for EJ257; uses a timing chain (typically no scheduled replacement unless issues arise).

Coolant Flush:

Every 30,000 miles or 2 years.

Brake Fluid Flush:

Every 2 years, regardless of mileage.

Ej257 Ring Land Failure:

Prone to ring land failure in cylinders 3 & 4, especially with aggressive tuning or sustained high heat. Manual provides guidance on piston ring installation and torque specs critical for prevention.

Head Gasket Leaks:

While less common on later EJ engines than earlier ones, it's a potential issue. Manual details inspection and replacement procedures.

Clutch Wear:

Can experience premature clutch wear due to high-performance nature and driving style. Manual covers clutch inspection and replacement.

Turbocharger Issues:

Potential for turbocharger failure if oil supply/return is restricted or if proper cool-down procedures are not followed. Manual details turbo diagnostics and replacement.

Dccd Failures:

The DCCD unit can develop issues over time; manual provides diagnostic steps.

Brake Fluid Type:

DOT 3 or DOT 4 (refer to manual for precise specification)

Power Steering Fluid Type:

Subaru Genuine ATF-HP or equivalent (check manual for exact spec)

📚 Vehicle History

Performance Legacy:

Subaru has a strong heritage in motorsport, particularly in the World Rally Championship (WRC), which heavily influenced the WRX STI's development and reputation.

Third Generation Introduction:

The 2006-2007 models represent the later phase of the second generation (GD) platform, with the STI receiving significant upgrades, including the EJ257 engine and the refined DCCD system, leading into the third generation (GR/GV) hatch/sedan introduced later.

Manufacturing Location:

Japan (Mainly Gunma Plant)

Production Numbers Sti:

Limited production compared to standard Impreza models, highly sought after by enthusiasts.

🏆 Awards & Recognition

Car And Driver 10Best:

The Impreza WRX (and by extension the STI) often received accolades for its performance and handling from automotive publications like Car and Driver.

Motorsport Legacy:

Continuously recognized for its rally-bred DNA and capability on and off the track.