The 2004 Subaru Impreza WRX STI represents the pinnacle of the second-generation WRX platform, a model year highly sought after by enthusiasts for its balance of raw capability and daily usability. This specific iteration of the STI cemented its reputation with a refined chassis and a significant power increase over its predecessors. Understanding the precise specifications of this model is essential for anyone considering a purchase, a restoration, or simply an appreciation of its engineering. The 2004 model year offered a compelling mix of performance, technology, and rally-bred heritage that remains relevant today.
Engine and Performance Specifications
At the heart of the 2004 Subaru Impreza WRX STI is its legendary horizontally-opposed engine, a design that delivers a low center of gravity and excellent balance. This model year saw the introduction of the EJ257 engine, a substantial upgrade in power and reliability. The technical specifications of this powerplant are a key reason for the car's enduring popularity among gearheads.
Engine Details and Output
The 2004 STI’s power comes from the EJ257 2.5-liter turbocharged boxer engine. This unit was meticulously engineered to handle the immense torque generated by its forced induction system. The result is a driving experience that is both visceral and controlled, characteristics that define the Subaru WRX STI philosophy.
Engine Code: EJ257
Configuration: Horizontally-Opposed (Boxer), 4-Cylinder
Displacement: 2,458 cc (2.5L)
Forced Induction: Twin-Turbocharged (Turbocharged Side-Mount Intercooler)
Horsepower: 300 hp @ 6,000 rpm
Torque: 290 lb-ft @ 4,000 rpm
Drivetrain and Chassis Engineering
The power from the EJ257 is sent to all four wheels via a robust and precisely engineered drivetrain. This system is the cornerstone of the STI's renowned grip and stability, especially in adverse weather conditions. The chassis was also significantly upgraded for the 2004 model, focusing on improving handling dynamics and driver confidence.
Drivetrain Components
The symmetrical all-wheel-drive system is paired with a manual transmission, which is the preferred choice for driving enthusiasts. The inclusion of a limited-slip differential helps optimize power delivery to the wheels with the best traction, reducing understeer and maximizing cornering performance. The chassis setup is designed to translate the engine's power efficiently to the road.
Transmission: 5-Speed Manual (Optional 4-Speed Automatic)
Drivetrain: Symmetrical All-Wheel Drive
Center Differential: Viscous Coupling
Front Differential: Helical Gear Limited-Slip
Rear Differential: Helical Gear Limited-Slip
Suspension, Brakes, and Wheels
The 2004 model year brought notable updates to the suspension, moving away from the more rudimentary setup of earlier years. The result is a smoother ride that doesn't compromise the car's sharp handling characteristics. The braking system was also upgraded to ensure the STI could match its performance with the necessary stopping power.
Front Suspension: Double Wishbone with Stabilizer Bar
Rear Suspension: Multi-Link with Stabilizer Bar
