Following a model-year 2011 revision that added significant handling enhancements, the Subaru WRX STI flagship performance model gains minor trim changes for 2012, along with a new-type available touch-screen, voice-control navigation system.
The 2012 Impreza WRX STI continues with a 305-horsepower turbocharged/intercooled Boxer engine, 6-speed manual transmission and the exclusive Multi-Mode Driver Controlled Center Differential (DCCD) version of Symmetrical All-Wheel Drive. The WRX STI is also equipped with Subaru Intelligent Drive (SI-DRIVE) and Multi-Mode Vehicle Dynamics Control (VDC) system, the latter featuring a track performance-optimized mode.
The 2012 WRX STI is available in both 5-door and 4-door models, and, like the 2012 Impreza WRX, continues on the platform used for the 2011 models. The new-for-2012 Impreza 2.0i models introduce a new version of the platform.
The new navigation system available for the 2012 Impreza WRX STI includes a 6.1-inch touch screen LCD display, voice control, iPod(R) control capability, iTunes(R) tagging, SMS text messaging capability, as well as XM(R) Satellite Radio and XM NavTraffic(R) (both XM services require subscriptions). The system plays through six speakers. Updated map data can be downloaded to a personal computer and then transferred into the vehicle's system via secure digital (SD) card.
Handling Refinement on the Nurburgring
Thorough and painstakingly detailed chassis development, including testing on Germany's famed Nurburgring racetrack, has helped make the current Impreza WRX STI models the best-handling cars Subaru has ever offered. The WRX STI debuted new chassis tuning for 2011, including higher-rate springs and thicker front and rear stabilizer bars, new pillow-ball bushings in front and stiffer bushings for the rear subframe that supports the double-wishbone suspension. This setup continues for 2012.
The WRX STI delivers ultra-crisp handling along with comfortable ride compliance. High-tensile-strength steel is used at key structural points and the suspension-mounting areas. Solid engine mounts help to minimize engine movement, which in turn enhances handling agility. Inverted struts used for the front suspension provide high bending resistance for quicker and more consistent performance under hard cornering. Aluminum front lower L-arms reduce unsprung vehicle weight.
Exclusive to the WRX STI, the Brembo Performance Brake System uses ventilated 4-wheel Super Sport anti-lock (ABS) disc brakes with Electronic Brake-force Distribution (EBD). Front discs measure 13.0 inches in diameter and use 4-piston, fixed-position calipers; the 12.6 in. rear discs use 2-piston, fixed-position calipers. Taking input from a lateral g-sensor, a steering angle sensor, a yaw sensor and a brake pressure sensor, Super Sport ABS can control the braking forces at each rear wheel independently, which optimizes braking ability during hard cornering to help reduce understeer. In contrast, conventional ABS systems control the rear wheels as a pair, reducing the braking force to both rear wheels equally.
The WRX Limited 4-door includes standard 18 x 8.5 in. BBS(R) forged aluminum-alloy wheels. Dunlop SP600 245/40R18 summer performance tires are used with the standard and optional wheels.
305-hp Turbo Boxer Engine
The WRX STI is powered by a 2.5-liter turbocharged/intercooled 4-cylinder Boxer engine, with Dual Active Valve Control System (Dual AVCS). The engine, which is exclusive to the STI model, produces 305 horsepower (SAE) at 6,000 rpm and 290 lb.-ft. of peak torque at 4,000 rpm. The 2012 WRX STI achieves the very stringent Bin 5 Tier 2-Federal (EPA) and LEV2-California Tier 2/Bin 5 emissions certification.
The engine is teamed exclusively to a 6-speed manual transmission. Incline Start Assist, featured on all Impreza models equipped with a manual transmission, can momentarily prevent the vehicle from rolling backward when being driven away from a stop on an incline.
The WRX STI engine is based on a specially reinforced semi-closed deck engine block with high-strength cast pistons. A semi-closed deck design provides the same cooling efficiency as an open-deck cylinder block but with the higher strength of a full closed deck. Special reinforcing ribs in the block provide additional strength, and the crankshaft is nitride-hardened.
The turbocharger produces a maximum of 14.7 PSI of boost, compared to 14.2 PSI in the standard WRX. The WRX STI exhaust system features an efficient high-flow rear catalytic converter, low backpressure muffler and two sets of dual-outlet chrome tailpipes.
SI-DRIVE Gives WRX STI Driver More Control
Exclusive to the WRX STI, Subaru Intelligent Drive (SI-DRIVE) technology 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. SI-DRIVE alters vehicle performance characteristics by regulating the Engine Control Module (ECM) and by fine-tuning the Electronic Throttle Control system.
With Intelligent mode selected, SI-DRIVE provides a more relaxed throttle response curve, making it useful for commuting in traffic, for example. "Sport" mode provides quick throttle responses and powerful, linear acceleration, making it ideal for everyday sporty driving. In "Sport Sharp" mode, SI-DRIVE modifies the engine's electronic throttle mapping to deliver super-quick throttle response and put down the power sooner.
Multi-Mode DCCD All-Wheel Drive with Three-Mode Vehicle Dynamics Control
The 2012 WRX STI is exclusively equipped with the Multi-Mode Driver Controlled Center Differential (DCCD) version of Subaru Symmetrical All-Wheel Drive. The system employs planetary-type differential gears with a nominal 41:59 torque split. A mechanical limited-slip type 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(R) torque-sensing limited-slip rear differential optimize side-to-side power distribution, helping to prevent the inside wheels from slipping during cornering.
The DCCD AWD system features three automatic modes. "Auto" mode provides the best all-around performance for most drivers and circumstances, varying the front/rear torque distribution automatically via the limited-slip type differential in response to vehicle acceleration, deceleration, steering angle, cornering force and wheel slippage. The "Auto (-)" mode makes less use of the center limited-slip differential (less locking factor) and holds the torque bias to the rear more frequently, which yields more handling-oriented steering characteristics.
For driving on slippery surfaces, such as gravel or snow, the Auto (+) setting tightens the LSD. In manual mode, DCCD offers six levels of center differential locking, allowing the driver to vary the front-to-rear torque distribution (up to 50:50 maximum) to optimize AWD performance for varying driving conditions.
Exclusive to the WRX STI, the Multi-Mode Vehicle Dynamics Control (VDC) stability and traction control system offers the driver three settings: "VDC Normal," "Traction" and "Off." The "Normal" setting provides the highest level of system engagement, utilizing traction control (TCS) and VDC. The "Traction" setting is more performance-oriented, employing less-restrictive VDC and disengaging the engine torque-reduction control. The "Off" setting disengages the VDC and the traction control functions.
Sporty, Spacious and Versatile Interior
The WRX STI's sport-oriented cockpit features performance-design front seats that integrate the backrest and head restraint into a single structure. The standard tilt and telescopic steering wheel is a three-spoke, leather-wrapped design embossed with the STI logo in its center. The wheel features control switches for Bluetooth(R) hands-free phone function. Standard aluminum-alloy pedal covers include the driver's footrest. The instrument panel electroluminescent gauges use indicator needles that sweep the gauge faces upon engine startup.
The compact layout of the double-wishbone rear suspension helps to minimize intrusion into the cargo area, providing a wide and deep luggage compartment. In the 5-door models, the wide and flat load floor can accommodate two Tour-size golf bags with the rear seat backs in the upright position. In the 4-door sedan model, which is 6.5-inches longer than the 5-door, the extra space provides for a larger, deeper trunk that can accommodate three Tour-size golf bags. A 60/40-split folding rear seat further boosts cargo capacity and convenience, and the 4-Door also features a rear seat fold-down center armrest.
Standard amenities that help make the WRX STI an excellent everyday driver include an automatic climate control system with cabin air filtration and the All-Weather Package that includes heated front seats, heated side mirrors and a windshield wiper de-icer.
The standard audio system features an AM/FM stereo with single-disc CD player and six speakers; a 3.5mm auxiliary input jack; Bluetooth hands-free calling and audio streaming; iPod control capability; a USB port and XM/SIRIUS Satellite Radio capability. Steering wheel controls for the audio system cruise control and Bluetooth are standard. The WRX STI Limited models feature a standard power moonroof and standard leather-trimmed upholstery.
All Subaru models utilize the proven Subaru Ring-Shaped Reinforcement Frame body structure with front and rear crumple zones, and all feature standard front seat side pelvis/torso airbags and side-curtain airbags. The Subaru Advanced Frontal Airbag System (SRS) features a passenger side front seat sensor module that detects weight - first determining if the seat is occupied, and if so by a child or adult - to control airbag deployment. As part of the system, the dashboard features an "Airbag" indicator light. There are 3-point seatbelts for all seating positions, including front height-adjustable seatbelts with electrically triggered pre-tensioners and force limiters.
Electronic Brake-force Distribution (EBD) provides precise control of braking pressure between the front and rear wheels based on the vehicle load to improve stability and stopping distances. Brake Assist analyzes the force and stroke on the brake pedal and increases hydraulic boost to provide enhanced emergency braking, also activating the ABS system early if needed.
About Subaru of America, Inc.
Subaru of America, Inc. is a wholly owned subsidiary of Fuji Heavy Industries Ltd. of Japan. Headquartered in Cherry Hill, N.J., the company markets and distributes Subaru Symmetrical All-Wheel Drive vehicles, parts and accessories through a network of more than 600 dealers across the United States. Subaru boasts the most fuel-efficient line-up of all-wheel drive products sold in the market today based on Environmental Protection Agency (EPA) fuel economy standards. All Subaru products are manufactured in zero-landfill production plants and Subaru of Indiana Automotive Inc. is the only U.S. automobile production plant to be designated a backyard wildlife habitat by the National Wildlife Federation. For additional information visit www.subaru.com