2015 Subaru WRX STI debuts at NAIAS

Of all the great vehicles in Subaru’s lineup, none are as exciting and well-loved as the WRX STI. The 2014 North American International Auto Show (NAIAS) in Detroit saw the debut of a new WRX, the 2015 Subaru WRX STI, to release later this year. A special 1,000 unit STI Launch Edition will be coming soon as well.

As the performance flagship for Subaru, the WRX STI has a dedicated group of hardcore fans it must always impress while still walking a fine line that allows Sub to bring in new buyers as well. With the 2015 Subaru WRX STI, it appears that the Japanese automaker famous for its Boxer engines has done both.


Rather than change what works, Subaru stuck with the now-legendary 2.5-liter, 305 horsepower Boxer for the 2015 WRX STI that has won it so many accolades and rally race wins. What’s changed is the body and chassis for the new sedan model.

A new four-door, wide-body design moves away from the more traditional hatchback / wagon look the WRX has sported before, but brings with it a stiffer chassis, firmer sprints, and a faster steering ratio. Subaru has also added Active Torque Vectoring to what many consider to be the world’s best all-whee drive system, which includes a new Multi-Mode Driver Controlled Center Differential (DCCD) for the Symmetrical All-Wheel Drive. Brembo performance brakes with Super Sport ABS finish off the chassis.

Alcantara seating is also introduced for the interior, with red and black leather bolsters and red stitching to accent the roomier cabin. Of course, this being a WRX STI means that the layout remains driver-focused  with a flat-bottom steering wheel and whiplash-reducing front seats with height-tilt adjustable head restraints and an available Harman/Kardon premium audio system to accent your dust-throwing mayhem.

The 2015 Subaru WRX STI Body totally changes

Everything about the new 2015 WRX STI is different when first viewed. From the front “nose cone” grille-bumper combination to the aluminum body and sedan styling, it’s very different. The headlights are narrower LEDs and the one piece grille and bumper are unusual for Subaru. The hexagonal grille is still there, though, letting people know it’s a Sub.


A functional hood scoop also denotes the car as a WRX, as do the unique tail lamp structures. The scoop is deeper set, giving better visibility for the driver. Faux carbon fiber surrounds the fender vents, foglight surrounds, and other details. The large trunk spoiler is standard as part of the new aerodynamic package that signifies the 2015 Subaru WRX STI.

The Chassis gets stiffer

The new body design sits atop a new chassis. This is a stiffer structure using more high-tensile strength steel than previous models did as well as several stiffening elements in key locations. This gives better steering and handling, which allows for the higher steering ratio of 13.0:1 on this new 2015 WRX STI. That’s only 2.5 turns lock-to-lock.

The front suspension remains an inverted-strut system for the great cornering agility the Subaru WRX STI has been known for. The aluminum lower L-arms reduce unsprung vehicle weight while the aluminum body reduces overall weight. The STI-tuned suspension is calibrated for the standard 18-inch wheels. The WRX STI Launch Edition and Limited models both have BBS forged aluminum-alloy wheels as standard.

The Engine and Drivetrain

The 2015 WRX STI retains the powerful Boxer engine that the WRX STI has been known for. This 2.5-liter turbocharged and intercooled four-cylinder employs a Dual Active Valve Control System (Dual AVCS), exclusive to the STI, producing a total of 305 horsepower at 6,000 rpm and 290 lb-ft of torque at 4,000 rpm.


This is mated to an exclusive reinforced six-speed manual transmission with an STI short-throw shifter in the Launch Edition model. Subaru Intelligent Drive (SI-DRIVE) powertrain management allows tailored driving characteristics for the driver from three selectable modes: Intelligent, Sport and Sport Sharp. This regulates engine output and throttle control in varying degrees of performance.

AWD with lots of initials

The 2015 Subaru WRX STI has DCCD (Multie-Mode Driver Controlled Center Differential) for its AWD, which is a planetary-type center differential gearing system with a 41:59 torque split (nominally). A mechanical limited-slip center differential augments an electronically-controlled center differential to enhance 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.


ATV (Active Torque Vectoring), an enhancement of the Multi-Mode VDC (Vehicle Dynamics Control) stability and traction control system, can apply brake pressure to the inside front wheel to facilitate more neutral cornering. The VDC system offers yet more driver choices, with three settings: “VDC Normal,” “Traction” and “Off.” Each provides respectively lesser degrees of system engagement, allowing the driver to tailor response for the driving situation. Active Torque Vectoring remains engaged for “Normal” and “Traction” modes.

The 2015 WRX STI is expected to enter showrooms later this year while the STI Launch Edition will be available in limited numbers (only 1,000 units) shortly thereafter.

Aaron Turpen
An automotive enthusiast for most of his adult life, Aaron has worked in and around the industry in many ways. He is an accredited member of the Rocky Mountain Automotive Press (RMAP), the Midwest Automotive Media Association (MAMA), the Texas Auto Writers Association (TAWA), and freelances as a writer and journalist around the Web and in print. You can find his portfolio at AaronOnAutos.com.