First Drive | 2015 Subaru WRX STI

At the LA Auto Show in November 2013, Subaru unveiled its new and improved WRX. Its new exterior, turbocharged FA20 engine, six-speed driveline and active torque vectoring worked well with the stiffer chassis to deliver a fun driving experience. As Subaru fans would expect, when a new WRX is released, an STI is sure to follow. At the Detroit Auto Show in January, that highly anticipated STI made its grand entrance. subaru-wrx-sti-2015-first-drive-141-001 Text by Richard Fong and Magnus Ohlaker // Impressions by Magnus Ohlaker // Photos by Richard Fong and Subaru of America


subaru-wrx-sti-2015-first-drive-141-002Subaru Tecnica International (STI), the motorsports division of Fuji Heavy Industries (parent to Subaru) has produced three World Rally Champions, as well as numerous performance versions of Subaru’s product line. The STI designation is an indicator of more than your typical Subaru, the WRX STI is Subaru’s flagship model and the platform most inspired by this rally heritage.

STI Revised

subaru-wrx-sti-2015-first-drive-141-003STI invested most of the development energy into improving the STI’s handling over the previous generation. Like the WRX, the new STI benefits from the use of high-strength steel in its chassis, resulting in a 41 percent stiffer platform that’s more responsive. In conjunction with the STI-only inverted dampers, forged-aluminum L arms, stiffer springs and a quicker, 13.0:1 hydraulic steering rack, the new STI enjoys a noticeable improvement in handling compared to its predecessor. To neutralize the STI’s characteristic understeer, Subaru incorporated its latest active torque vectoring technology, which functions in conjunction with the vehicle dynamic control. This system utilizes the brakes to help bias torque to the outer wheel to improve turn-in. [pullquote]STI INVESTED MOST OF THE DEVELOPMENT ENERGY INTO IMPROVING… HANDLING OVER THE PREVIOUS GENERATION[/pullquote]The resculpted exterior takes cues from the WRX concept that Subaru unveiled at the 2013 New York Auto Show. The aggressive front and rear fascia, along with wide bodylines, offer a distinct departure from the shape of the outgoing GVB chassis. A trademark rally-inspired wing fitted to the trunk lid sets the STI apart from its siblings.

What’s New Inside

subaru-wrx-sti-2015-first-drive-141-010Along with the exterior improvements come measurable upgrades to the driving environment. The roomier cabin gains two inches of rear seat legroom thanks to a one-inch-longer wheelbase, while the more steeply raked A-pillars add to the feeling of spaciousness. Gone are the fixed-headrest seatbacks in favor of front seats featuring height and tilt adjustable headrests for whiplash reduction. The STI’s new flat-bottom steering wheel houses the controls for cruise control, audio and hands-free telecommunications (when paired with a Bluetooth-enabled phone). Essential driving controls placed within easy reach include the Subaru Intelligent-Drive (SI- Drive) knob, the driver-controlled center differential and climate controls. subaru-wrx-sti-2015-first-drive-141-008A new and easy-to-read gauge cluster features a 3.5-inch LCD information display between the tach and speedo, delivering status and content to the driver in vivid color. The dash incorporates a 4.3-inch multi-function display that (in addition to serving as a backup camera monitor) shows climate control settings, Bluetooth© status and a digital boost gauge. subaru-wrx-sti-2015-first-drive-141-011If you’ve missed having a better-than-base-model sound system in your Subaru, an optional 440-watt Harman/Kardon audio system is available for the first time. For those seeking a one in 1,000 limited edition equipment package, the WRX STI Launch Edition is for you. The Launch Edition, available only in World Rally Blue, features an STI short-throw shifter, blue Alcantara® trimmed seats, BBS forged alloy wheels and keyless access and start.

New Meets Old

One aspect of the new STI that isn’t really new is its powertrain. Rather than equipping the STI with a variant of the new FA-Series engine like the WRX, the STI relies on the latest version of the EJ257 engine and the six-speed transmission that has propelled STIs since 2004. According to Subaru’s product communications manager, Jessica Tullman, the focus was to improve vehicle handling, since the port-injected EJ257 engine that carries over from the outgoing GVB STI has a race-proven development pedigree with aftermarket support. Continuing to offer 305 horsepower and 290 lb-ft of torque, the EJ257 brings with it the prominent and much lamented characteristics of turbo lag. However, since the aftermarket has already embraced this engine for a number of years, power adders and upgrades are plentiful. subaru-wrx-sti-2015-first-drive-141-009In addition to the engine, the STI retains its performance-oriented driveline. The six-speed transmission that has equipped STIs for a number of years continues to transmit power from the crankshaft to the transfer case. It features shorter gearing than the WRX, and the rod linkage offers a more connected feel without the notchiness of the cable linkage of the WRX. The transfer case houses a mechanically and electronically controlled center Limited Slip Differential (LSD) that permits user-selectable torque splits with a nominal split of 41/59. Locking differentials turn the wheels, with a helical LSD at the front and a TORSEN® LSD at the back. By comparison, the WRX’s center differential has a nominal torque split of 50/50 and open differentials at the front and the back. These proven driveline components ensure optimum power delivery to all four tires. The STI’s larger Brembo brake system, featuring 13-inch rotors up front with 12.6-inch rotors out back, also carry over from the previous generation.