With a bore and stroke of 87.5 × 83.1 mm, the engine’s short stroke reduces overall engine height, while its hot V configuration positions one of its two turbos in each engine bank. The engine also features dry-sump lubrication and an oil pan that has been made thinner than usual.

The engine’s power is transmitted to the rear transaxle via a CFRP torque tube. In addition to a motor-generator, the transaxle integrates a newly developed 8-speed automatic transmission, which uses a wet-start clutch in place of a torque converter, and a mechanical limited-slip differential.

The motor-generator, which is positioned in front of the transmission, is used to help make up for the momentary lag in torque response that occurs during acceleration and gear changes, while providing a direct feel that surpasses that of the GAZOO Racing Direct Automatic Transmission used in the GR Yaris and GR Corolla.

The 8-speed automatic transmission of the GR GT is being developed toward achieving world-class shift speed, as well as shift control that allows shift manipulation at will, even when in D-range automatic shift mode.

To minimize the wheelbase in consideration of overall vehicle packaging, the rear transaxle, after relaying to its far end the power that has been conveyed from the engine and through the electric motor and automatic transmission, uses a conical gear to reverse the direction of that power, which then turns the driveshaft through the mechanical limited-slip differential.

This structure is unique among front-engine, rear-wheel-drive vehicles and represents the optimization for use in the GR GT of the mechanism used in all-wheel-drive vehicles. The adoption of a rear transaxle and the optimal placement of the drive battery, fuel tank, and other heavy components have resulted in a 45:55 front-to-rear weight distribution, contributing to ease of vehicle handling.

Development of the powertrain involved advancing studies through the use of race development driving simulators and system benches onto which entire powertrain systems could be mounted, while consideration was also given to thermal management, mounting position, and serviceability. To ensure continued sales, development is being undertaken to comply with increasingly stringent emissions regulations.

The GR GT3 also features a 4.0-litre, V8 twin-turbo engine — many of the structural components of which are shared with those of the engine in the GR GT. The basic structures of the aluminum space-frame chassis and front-and-rear double-wishbone suspension system have also been developed so that many of their components can be shared with the GR GT3.

The GR GT’s styling was developed under an “aerodynamics first” concept in which aerodynamics engineers and exterior designers worked as a single team. With GR GT boasting a top speed in excess of 320 km/h, aerodynamic performance was one of the most vital concerns.

Whereas in conventional production vehicle development exterior styling is set before consideration of aerodynamic efficiency and cooling performance, the GR GT’s being envisioned as a road-legal race car required a rethinking of the process. Aerodynamics engineers experienced in FIA WEC competition vehicle development joined the GR GT development team and engaged in thorough discussions with vehicle designers, leading to the establishment of overall vehicle packaging based on an “aerodynamic model” — the aerodynamic design team’s proposal for the ideal form.

It was only after such that exterior designers prepared design sketches with mass production in mind, eventually leading to finalization of vehicle styling in a process that was the reverse of the normal approach. Aerodynamics engineers and exterior designers worked together to achieve styling that pursues aerodynamic and cooling performance.

Interior styling, as well, was meticulously crafted without compromise, based on ergonomics aimed at achieving the optimal driving position from a professional driver’s perspective and visibility needed for performance driving. Naturally, in addition to circuit driving, care has been taken to ensure suitability for everyday use.

The GR GT’s interior styling centered on prioritizing driving position and visibility above all else in an effort to achieve an optimal design that would be suitable for both professional and non-professional drivers, as well as for circuit and daily use.

Pursuit of the ideal driving position, coupled with consideration of interior styling, renewed awareness of the importance of ensuring sufficient visibility, as well as a sense of being protected. Particular attention was paid to excellent operability, with driving-related switches placed near the steering wheel and positioned and shaped for intuitive operation.

For ease of visual recognition even during circuit driving, substantial focus was also given to the gauges, for which the width, height, and position of information displays, such as the shift-up and gear selection indicators, were determined through a process of trial and error.

As for low weight with high rigidity, which constitutes the second key element, the GR GT features Toyota’s first all-aluminum body frame. Additionally, the appropriate use of carbon fibre reinforced plastic (CFRP), plastic, and other materials in the body panels help to create a strong yet light body.

A high level of rigidity has been achieved by positioning large aluminum castings in the frame’s main structure, as well as through the optimal placement of aluminum extrusions and other components, along with the use of advanced joining technologies. Additionally, the model’s body panels are made of aluminum and CFRP.

The suspension features a newly designed, low-mounted double-wishbone system with forged aluminum arms at both the front and rear. Its characteristics were developed from scratch, with a focus on linear response and a high level of controllability, from everyday use to spirited driving.

The tires are Michelin Pilot Sport Cup 2 tires developed exclusively for the GR GT. Since the early stages of development, the design of both the suspension and the tires has involved working with professional drivers in the use of simulators and agilely conducting test runs and simulator evaluations in pursuit of optimal performance for the GR GT that will help to enable the driver to seamlessly interact with the car on circuits, as well as on winding and other public roads.

Brembo carbon discs are used in the brakes, and vehicle behavior control during braking was developed together with professional drivers. The GR GT’s Vehicle Stability Control system allows multi-stage adjustment of driving force and braking control, enabling driver selection of the vehicle control difficulty level based on driving skill and encountered weather conditions to help facilitate an enjoyable and secure driving experience.

This setup is also used in TGR’s Nürburgring 24-hour endurance race vehicles and is an example of technology honed through competing in motorsports. Additionally, the basic structures of the aluminum space-frame chassis and front-and-rear double-wishbone suspension system have been developed so that many of their components can be shared with the GR GT3.