Subaru Tecnica International (STI), a wholly owned subsidiary of Subaru Corp., introduces the limited edition STI S209, the first-ever S-line STI product produced exclusively for the U.S. market.
As an S-line product, the STI S209 encompasses upgrades in power, handling, aerodynamics and driver engagement, and undergoes final assembly in Kiryu, Japan, where it receives engine modifications and bodywork alterations that in total require it to be homologated for the U.S. by STI, according to the company. Thus, the S209 is considered the first STI-built Subaru sold in the U.S.
The S209 carries on a high-performance tradition that dates to STI-built models that were exclusive to the Japanese domestic market: the 2000 S201 through the 2018 S208, according to the company.
Designed with a focus on high-performance driving, the S209 draws inspiration and tech transfer from STI’s most formidable track machine: the WRX STI Nürburgring Challenge race car, which won the SP3T class at the 2018 24 Hours of Nürburgring, marking the fifth time STI dominated the SP3T class at the grueling endurance race.
The S209, like the Nürburgring Challenge racecar, wears an expanded widebody exterior treatment, which extends the vehicle’s overall width to 72.4 inches, or 1.7 inches wider than a standard WRX STI.
The bulging fenders accommodate wider front/rear tracks (plus-0.6 in front/rear) and 265/35 Dunlop SP Sport Maxx GT600A summer-only tires wrapped around lightweight 19-by-9-inch forged BBS alloy wheels. The all-new tires, developed exclusively for the S209 by Dunlop, are a significant contributor to the car’s tenacious maximum lateral grip of over 1.0G.
Vents on the front fenders provide additional engine cooling, while vents on the rear fenders rectify air turbulence to reduce drag. Brembo brakes, with cross-drilled steel rotors and 6-piston monoblock front calipers and 2-piston monoblock rear calipers, provide stout stopping force, thanks in part to upgraded high-friction pads that deliver improved fade resistance.
Underneath the S209’s broader body are specially developed Bilstein dampers, stiffened coil springs, a 20mm rear stabilizer bar and pillow-type bushings for the front/rear lateral links. The S209 incorporates reinforcements to the front crossmember and rear subframes and, a la the Nürburgring race car, a flexible front-strut tower bar and flexible front/rear draw stiffeners.
The flexible tower bar, unlike a conventional rigid bar, is split and joined with a pillow ball joint in the center to be longitudinally mobile while helping laterally stiffen the body of the car. The result is optimum tire grip during lateral moments combined with compliant ride during longitudinal moments.
Meanwhile, the draw stiffeners apply tension between the body and crossmember to optimize chassis flex, improving stability when cornering and delivering better ride, handling and steering response.
Other Nürburgring race car tech that trickles down to the S209: front, rear and side under-spoilers; front bumper canards; and carbon fiber roof panel and rear wing.
A thoroughly reworked version of the legendary EJ25 2.5-liter turbocharged BOXER engine propels the S209. Featuring an STI turbocharger manufactured by HKS, the EJ25 serves up an estimated 341 hp, thanks in part to a larger turbine and compressor as well as maximum boost pressure that has been increased to 18.0 psi.
Proudly displaying an S209 serial number plate, the enhanced BOXER engine utilizes forged pistons and connecting rods that are both lighter and stronger. Midrange torque, too, gets a notable bump, up 10 percent at 3,600 rpm, delivering higher corner exit speeds.
For ultimate driver engagement, the S209 comes exclusively with a close-ratio 6-speed manual transmission that routes power to a full-time Subaru Symmetrical All-Wheel Drive system with front/rear limited-slip differentials, a Driver Controlled Center Differential (DCCD), Active Torque Vectoring and Multi-Mode Vehicle Dynamics Control.
A recalibrated SI-Drive system offers three modes: Intelligent (I) for improved fuel economy and smoother power control; Sport (S) for optimized power balance between response and control; and Sport Sharp (S#) for achieving the best acceleration times.
STI engineers recommend Sport over Sport Sharp for circuit driving, as the less aggressive throttle map allows for greater driver control.
To feed more air to the EJ25, the S209 uses a high-flow intake system featuring a new intake duct, induction box with conical air filter, silicone turbo inlet duct and, a nod from the 2004-’07 WRX STI, an intercooler water spray system that lowers intercooler temperature via manually operated steering wheel paddles.
More air demands more fuel, so the S209 receives a new high-flow fuel pump, larger fuel injectors and an STI-tuned engine control module. High-performance mufflers deliver 17 percent less airflow resistance while larger, hand-polished stainless-steel exhaust tips—101mm in diameter—deliver aggressive appearance and acoustics.
The S209 receives multiple tweaks to elevate it from other STI sedans. An STI badge replaces the traditional Subaru star cluster on the center of the D-shape steering wheel, which is wrapped in Ultrasuede with silver stitching, a treatment that carries over to the lid of the center console storage box.
An S209 serial number badge resides on the center console, and S209 badges adorn the passenger-side dash and the headrests of the Recaro front bucket seats, which feature new silver-hued inserts. Outside, special S209 badges are affixed to the front grille and fenders as well as the rear decklid.
Only around 200 units of the STI S209 will be built, earmarked exclusively for the U.S.