The two manufacturers are represented by sister brands Cadillac and Acura, respectively, in the IMSA SportsCar Championship, where they just completed the maiden season of a hybrid-infused GTP class over nine races in 2023.
In the build-up, the series allowed each manufacturer to create its own powerplant, with rules in place such as a total system output (gas plus electric motor), which could not exceed 500 kW (671 horsepower). Additionally, per Section 5.2.1 of the 2023 IMSA Technical Regulations, the ICE (Internal Combustion Engine) speed limitation was set at 10,000 rpm.
The total output of the ICE and ERS was established between 480-520 kW (644-697 horsepower), and that was measured at the driveshaft by torque sensors and subject to BoP (Balance of Power) adjustment.
Cadillac developed a 5.5-litre naturally aspirated 32-valve V-8, while Acura opted for a twin-turbo 2.4-litre V-6.
The development in IndyCar is dramatically different, with both Chevrolet and Honda more in collaboration of a single unit that fits both respective 2.2-litre engines (V6), which debuted in 2012. The initial hybrid concept was developed by Mahle prior to being taken over by the manufacturers.
Source: Autosport