Continuing the “WRX on steroids” theme, the new 2015 Subaru WRX STI offers up a number of major improvements over its predecessor, not the least of which is a beefed up version of the standard Impreza’s body structure.
Set to be offered – at least initially – only as a four-door sedan, the WRX STI features a 305 horsepower turbocharged 2.5-liter four-cylinder engine hiding behind a more aggressive body kit than before. Making its peak horsepower at a high 6,000 rpm, the 2.5 is perhaps more notable for its 290 lb-ft. of torque peaking at 4,000 rpm. The Boxer configuration four-cylinder features dual active valve control and a reinforced six-speed manual gearbox. Unlike the more plebeian WRX, no automatic transmission will be on offer.
Subaru’s Intelligent Drive – or SI-Drive – powertrain management system returns, offering Intelligent, Sport and Sport Sharp modes accessed by a center console-mounted dial. Each mode offers up more sport-oriented tuning of the engine control module and electronic throttle control system.
Setting the WRX STI further apart from the standard WRX is its Multi-Mode Driver Controlled Center Differential mated to Subaru’s existing all-wheel-drive systsem. A planetary-type center differential delivers up a nominal 41/59 torque split (front/rear), while a mechanical limited slip center differential helps apportion that power fore and aft in one of three automatic modes. A manual mode lets drivers pick one of six pre-selected center differential locking levels for various driving situations.
WRX STI also now includes Active Torque Vectoring, which builds on the car’s stability and traction control systems to apply brake pressure to the inside front wheels for a more neutral cornering feel. Notably, the stability control now features three settings – normal, traction control only and off.
Getting the look right
The WRX STI remains based on the WRX, which is in turn an amped-up Impreza. A unique aluminum hood and special doors, quarter panels, bumpers and lights set the WRX STI even further apart. Sitting on the aluminum hood is a functional hood scoop set more deeply than before to provide better visibility.
Carbon fiber-like surrounds amplify the fog lamps and, of course, a massive rear spoiler is included. LED tail and center high mount stop lamps are included.
Beneath its new look, the WRX STI rides on stiffer platform that makes use of more high tensile steel than before. Special stiffening elements have been specified to tighten things up even further. Unique 18-inch alloy wheels wrapped in 245/40R-18 summer tires are standard. WRX STI Limited trims gain BBS forged alloy wheels.
A flat-bottomed steering wheel delivers what is now electric-boosted power steering boasting a 13.0:1 steering ratio (2.5 turns lock-to-lock), compared to the previous WRX STI’s 14.5:1 (and 2.8 turns).
Unlike the standard WRX, the STI uses an inverted strut front suspension to improve cornering. Aluminum lower L-arms up front reduce unsprung weight.
Inside, the WRX STI takes advantage of the standard Impreza’s improved cabin. A special STI Design electroluminescent gauge panel uses a 3.5-inch LCD screen for certain functions including the selected gear. Safety enhancements include a knee airbag for the driver’s side.
WRX STIs will come loaded up with dual-zone automatic climate control, heated seats and a Bluetooth-enabled audio system. WRX STI Limiteds build on the standard configuration with leather upholstery, a power moonroof, an eight-way power driver’s seat and harman/kardon audio. A touch-screen navigation system and a proximity key are optional on both standard and Limited grades.
An STI Launch Edition – limited to just 1,000 units – will be the first model to arrive in showrooms. It adds to the standard WRX STI gold-painted BBS alloy wheels, blue and black leather/Alcantara upholstery, a proximity key and a short-throw shifter.
Pricing for the WRX STI will be announced closer to the car’s on sale date this spring.
Live images by Mark Elias.
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