Just weeks after unveiling the all-new Impreza WRX sedan, Subaru has pulled the wraps off the even more high-performance 2015 Impreza WRX STI at the 2014 North American International Auto Show. Under the hood is Subaru’s 4-cylinder 2.5-liter turbocharged BOXER engine, which is exclusive to STI models. The mill makes 305 horsepower at 6,000 RPM and peak torque of 290 pound-feet at 4,000 RPM A special 6-speed manual transmission sends power to all wheels through Subaru’s Multi-Mode Driver Controlled Center Differential (DCCD) Symmetrical All-Wheel Drive sytem.
Underpinning the STI is a stiffer platform incorporating more high-tensile steel than the outgoing model. Subaru says the stiffer chassis increases turn-in response, while a quick 13:0:1 steering ratio provides a quick 2.5 turns lock-to-lock. As on previous models, the 2015 STI utilizes an inverted front strut suspension system and aluminum front lower L arms. The STI-tuned suspension teams with standard 18-inch wheels and 245/40R18 summer performance tires, with the WRX STI Launch Edition and WRX STI Limited models featuring BBS forged aluminum-alloy wheels.
New for the 2015 WRX STI is Active Torque Vectoring, which joins a host of proven handling technologies that includes Multi-Mode Driver Controlled Center Differential (DCCD) Symmetrical All-Wheel Drive, Multi-Mode Vehicle Dynamics Control, and a Brembo Performance Brake System with Super Sport ABS. The DCCD system uses planetary-type center differential gears with a nominal 41:59 front:rear torque split made possible by a mechanical limited-slip type center differential augmenting an electronically-controlled center differential to enhance torque transfer performance.
On the outside, the aggressive front clip of the WRX STI doesn’t differ too greatly from the standard WRX — a departure from prior models. An aluminum front hood is meant to reduce weight over the front wheels, and incorporates a large fully-functional hood scoop. The fat fenders, detailed doors, narrow headlights, different taillight cluster, and the scooped hood drive home the STI’s identity. Of course, an STI wouldn’t be an STI without the dramatically-oversized rear-wing, quadruple-exhaust tips, and an aggressive rear diffuser. The new model delivers on all accounts.
Inside, Subaru says the new STI is roomier than before. A narrower A-pillar has been pulled forward nearly 8-inches at the base for improved forward visibility, while lower side sills and wider opening doors make entering and exiting the car easier. Soft touch materials have been used on the dashboard, doors and center console armrest, adding to the interior’s premium feel.
Standard features for the new model include cruise control, heated front seats, dual-zone automatic air conditioning, a flat bottom leather-wrapped steering wheel, a split-folding rear seat, and aluminum pedal covers. The standard stereo incorporates Bluetooth streaming audio, iPod connectivity and an MP3 jack. STI Limited models feature additional amenities including a leather trimmed upholstery, a premium Harmon Kardon audio system, an 8-way power drivers seat and a sunroof. Meanwhile, standard safety features include antilock brakes, knee airbags, pelvis/torso airbags, and side curtain airbags.
Subaru will build 1,000 Launch Edition models with trademark STI design features like gold BBS wheels and WR Blue paint. The commemorative versions will also include a short-throw shifter.