A new twin-turbo V8 developed by the racing division of the Toyota Motor Corporation represents the propulsion heart of two new company prototypes, “GT” and “GT3.” This compact unit, featuring dry-sump lubrication and a “hot-V” architecture, has been designed to achieve maximum power density, maintain the lowest possible center of gravity, and integrate seamlessly with high-performance hybrid systems
The racing division Toyota Gazoo Racing unveiled these two prototypes in recent months. Both are intended for the motorsport-oriented high-performance road car segment. One targets customer racing, while the other meets the technical and performance requirements needed to compete in the FIA GT3 Championship category.
The two cars—designated GT and GT3—share the same technical foundation, drawing heavily on the experience accumulated by Toyota Gazoo Racing in endurance racing, particularly in the FIA World Endurance Championship. They therefore represent high-performance vehicles built around engineering and technical solutions derived directly from motorsport.
Development began with the GT prototype, whose overall vehicle packaging was designed with one primary constraint: minimizing the center of gravity of the powertrain, driving position, and main subsystems.
The front-mounted V8 engine, the rear transaxle transmission, the hybrid system, and all auxiliary components were therefore positioned as low as possible. This configuration results in a weight distribution close to 45:55 in favor of the rear axle, aimed at ensuring optimal balance between stability, traction, and predictable dynamic behavior under extreme driving conditions.
The same solutions also improve traction when exiting corners and steering precision at high speeds. The car’s dimensions—4,820 millimeters in length, 2,000 millimeters in width, and only 1,195 millimeters in height, with a 2,725-millimeter wheelbase—reflect proportions specifically designed to reduce load transfer and enhance responsiveness during directional changes.
Within this framework, the vehicle’s final mass was also carefully controlled to remain below 1,750 kilograms, a particularly notable achievement considering the presence of a hybrid powertrain and a structure engineered to withstand high dynamic loads.
The V8 Heart
The technical centerpiece of the GT is its twin-turbo V8 engine, a 3,998-cc unit that represents the first propulsion system with this architecture intended for a production Toyota model.
The bore and stroke measure 87.5 millimeters and 83.1 millimeters, dimensions that help limit the engine’s vertical development. Meanwhile, the “hot-V” configuration, with the turbochargers housed between the cylinder banks, shortens exhaust manifold lengths, improves transient response under load changes, and further lowers the engine’s center of gravity.
The adoption of dry-sump lubrication, with an extremely shallow oil pan, further contributes to the low engine placement while ensuring perfect lubrication even under high lateral acceleration, conditions typical of track use.
The V8 is paired with an electrified hybrid system featuring a single electric motor integrated into the rear transmission. This layout concentrates significant mass on the rear axle, improving the car’s overall balance and torque management.
The configuration therefore combines:
- a front-mounted internal combustion engine,
- a rear-mounted electric motor,
- and a new-generation eight-speed automatic transmission.
Unlike conventional automatics, this gearbox does not use a torque converter and instead relies on a wet multi-disc clutch, enabling faster gear shifts, reduced mechanical losses, and improved overall efficiency.
The connection between the engine and the rear transaxle is made through a composite driveshaft built from CFRP (Carbon Fiber Reinforced Polymer). This material—carbon fibers embedded in a polymer matrix, typically epoxy resin—offers a specific weight about one quarter that of steel, tensile strength up to seven gigapascals (about 71 tons per square centimeter), and a very high elastic modulus.
Torque transfer to the wheels is further managed by a custom mechanical limited-slip differential capable of handling the 650 horsepower and 850 newton-meters of torque produced by the hybrid powertrain.
These figures would enable a top speed exceeding 320 km/h, placing the prototype firmly within the ultra-high-performance supercar segment.
Motorsport-Derived Structure and Dynamics
The project also introduces Toyota’s first chassis entirely made from aluminum alloy, produced through a combination of large cast components, extruded sections, and panels assembled with advanced joining techniques derived from motorsport.
This solution provides an optimal balance between structural rigidity and weight, an objective further supported by the bodywork, which combines aluminum alloy panels with carbon-fiber composite materials.
The suspension and braking systems are also racing-derived. The suspension features double wishbone geometry on both axles, with forged aluminum control arms and kinematics specifically designed to ensure progressive response and precise control of camber and roll.
Braking is handled by carbon-ceramic discs from Brembo, essential for resisting brake fading and maintaining consistent performance under extreme conditions.
Completing the package are specially developed Michelin Pilot Sport Cup 2 tires, sized 265/35 ZR20 at the front and 325/30 ZR20 at the rear, designed to maximize grip and lateral stability.
The aerodynamic development followed a “reverse design” approach, meaning the vehicle’s shape was defined primarily by aerodynamic requirements before stylistic considerations. The objective was to maximize downforce, efficiency, and cooling of mechanical components, drawing on experience gained in endurance racing.
From GT to GT3
From this technical foundation also emerges the GT3 version, intended for customer racing in compliance with FIA GT3 regulations. It shares the same mechanical architecture, chassis, and powertrain as the GT prototype but features slightly different dimensions and even more extreme aerodynamics optimized for track use.
Tttle: Toyota twin-turbo V8 biturbo 4.0 and “Gr Gt”: ready to race
Translation with ChatGPT
