Subaru officially lifted the covers of the much-anticipated WRX STI performance sedan at the 2014 North American International Auto Show in Detroit. To celebrate the debut, Subaru of America is offering a limited to 1,000 units 'Launch Edition' in WR Blue paint with gold BBS forged alloys and unique interior trim.
The bodywork of the WRX STI is generally based on the recently debuted WRX sharing the same dimensions at 4595mm long, 1795mm wide, and 1475mm tall, with a wheelbase of 2650mm. The large rear wing and 18-inch STI wheels however significantly sets it apart from the WRX, with STI badges providing finishing touches. To further improve power-to-weight ratio, the hood is made of aluminum. At the rear, a aero diffuser, LED taillights and an LED center high-mount stop lamp (CHMSL) leave a distinctive signature.
Under the hood is a 2.5-liter turbocharged and intercooled Boxer engine with Dual Active Valve Control System (Dual AVCS) producing 309 PS @ 6000 rpm (305 hp) and 393 Nm (290 lb-ft) of toque carried over from the previous Impreza WRX STI (the Philippine-market edition is rated at 300 PS and 400 Nm). The engine is mated to a specially reinforced six-speed manual gearbox with Incline Start Assist to momentarily prevent the car from rolling backward when being driven away from a stop on an incline. Launch Edition models will get an STI short-throw shifter.
To pay tribute to its rally-bred heritage, the chassis has been stiffened making use of more high-tensile steel and addition of special stiffening elements. The improvements have resulted in quicker steering response, the steering ratio has also been improved to 13.0:1 providing a 2.5 turns lock-to-lock versus 14.5:1 and 2.8 for the WRX. Dampers and springs were also retuned to attain better handling characteristics. It will rolls on 18-inch wheels wrapped with 245/40R18 tires, while the limited launch model gets BBS forged aluminum-alloy versions.
Active performance driving aids come in the form of Active Torque Vectoring, Multi-Mode Drive Controlled Center Differential (DCCD), Symmetrical All-Wheel Drive, Multi-Mode Vehicle Dynamics Control and Super Sport ABS with the Brembo performance brakes.
The DCCD system uses planetary-type center differential gears with a standard 41:59 torque split. A mechanical limited slip center differential combined with an electronically controlled center differential improves torque transfer performance. Sensor inputs that include steering angle, throttle position, RPM, lateral-g, yaw, brake, ABS and wheel speed govern torque transfer response. A helical-type limited-slip front differential and a Torsen torque-sensing limited-slip rear differential optimize side-to-side torque distribution.
The DCCD AWD system features three automatic modes, each using varying degrees of center differential locking to match different driving situations. In manual mode, the driver can select one of six center differential locking levels to suit the driving situation.
The Subaru Intelligent Drive (SI-DRIVE) powertrain management system as found in the previous model allows the driver to tailor the car’s driving characteristics by choosing from among three selectable modes - 'Intelligent', 'Sport' and 'Sport Sharp' using a rotary dial on the center console.
Inside, the driver-centric cockpit features new Alcantara seating surfaces accented by red and black leather bolsters and red stitching set the tone for the upgraded and roomier cabin. As with the WRX, it will come with a motorsports-inspired flat-bottom steering wheel with integrated audio and Bluetooth controls. An STI Design electroluminescent gauge panel gets a new 3.5-inch central LCD screen that displays various functions, including low-level warnings for oil and windshield washer fluid and the selected gear. For enhanced safety, it is fitted with new whiplash-reducing performance-design front seats with height and tilt-adjustable head restraints.