Subaru Corp. and its motorsport subsidiary, Subaru Tecnica International Inc. (STI), have revealed two electric concept models, at the Tokyo Auto Salon 2022 held from January 14 to 16 at the Makuhari Messe convention center in Chiba, Japan.

One is based on the Solterra all-electric SUV that made its world debut in November 2021, but the more interesting for the motorsports- and EV-minded enthusiast is the STI E-RA concept. It previews the STI E-RA electric race car being developed under STI’s near-future motorsport study project launched with the aim of gathering experience with new technologies in the world of motorsports for the carbon-neutral era.

The first goal of the model is to try to record a lap time of 400 seconds (6 min, 40 s) in a time attack at the Nürburgring circuit from 2023, but first, its development will conduct driving experiments including at circuits in Japan in 2022.

STI will highlight Subaru’s uniqueness, such as the “pleasure of driving” and an “absolute sense of security,” more prominently in the future, by capitalizing on the brand’s strength in “all-wheel control technology.” It will do this in the STI E-RA to control the high maximum system output of 800 kW (1088 PS) with its newly adopted, proprietary, four-motor, four-wheel torque-vectoring technology.

The racer’s motors—high-torque, high-speed units with an integrated inverter and gearing for hyper EVs—were developed and supplied by Yamaha Motor Co., Ltd. The motors are fed by a 60-kWh lithium-ion battery pack.

According to Yamaha, the motor units the vehicle will use were developed to be “emotional electric engines” that leverage its technologies and engineering experience. Specifically, it cites the application of its casting and machining technologies accrued through developing engines, and the adoption of high-efficiency segment conductors, making the units achieve high output while being compact in size.

Yamaha exhibited a prototype of its Hyper-EV electric motor at the Automotive Engineering Exposition 2021 Yokohama in May. It showed a 350-kW motor and a unit installation of four 350-kW units.

The oil-cooled IPMSM (Interior Permanent Magnet Synchronous Motor) is aimed at use in hyper-EV models and other offerings in the high-output mobility segment. Yamaha began accepting orders for commissioned prototype development in April.

Since 2020, the company has been accepting commissions for developing prototype electric motors for automobiles and other mobility applications in the 35-200 kW range. The 350-kW class operates at 800 V and its main feature is its compact construction, with the mechanical and electrical components as a single entity and integrating the gear and inverter into one unit.

In July 2021, the company reviewed its Yamaha Motor Group Environmental Plan 2050 originally formulated in 2018 and set a new goal of aiming for carbon neutrality throughout all of its business activities—including across the life cycles of its products—by 2050. Among the changes, Yamaha set a goal of reducing Scope 3 CO₂ emissions (emissions produced from the company’s value chain through the use of its sold products) by 90% by 2050 compared to 2010. The commissioned development of the prototype electric motors to be used by STI is one of the company’s initiatives toward achieving this goal.

The unique torque vectoring technology of the STI E-RA car using the Yamaha motors equalizes the balance to the grip limit of each of the four wheels with a driver-focused control system whose highest priority is “the pleasure of driving.” This raises the grip level to the maximum and stabilizes the car body’s position.

To realize this goal, the system calculates the signals from sensors for wheel speed, vehicle speed, steering angle, g-force, yaw rate, brake pressure, and wheel load, determines the driving/braking torque at each wheel to gain a targeted stability factor and provide instructions to the inverter. Directly attaching the motors to the wheels enables a high level of responsiveness and direct control of car-body yaw.

Engineers determined this to be the best direction for its development work since this system can maximize a vehicle’s kinetic performance while satisfying future motorsport regulations for the FIA E-GT category.

STI says it will continue to strive in motorsports to refine its technology to keep creating cars that allow its customers to enjoy driving while feeling safe and comfortable. The organization will also use the insight gained from this project as an initiative for “a future electrified society,” creating new values so that cars will remain enjoyable to enrich the lives of customers, in an increasingly decarbonized world, for all Subarus.