The latest in a line of successful Acura endurance racing prototypes, the ARX-06 features Acura-specific bodywork and aerodynamics based around an all-new ORECA LMDh chassis, which utilizes an electrified hybrid power unit featuring an equally new, bespoke twin-turbocharged 2.4 liter V6 internal combustion engine designed, developed and manufactured by Honda Performance Development [HPD] the racing arm for Acura Motorsports in North America. In preparation for the 2023 IMSA season, Acura and HPD work on the prototype race car ahead of its premiere at the 2023 Rolex 24 at Daytona.
The ARX-06 was developed by Honda Performance Development (HPD) in Santa Clarita California to compete in the IMSA Sportscar Championship and the FIA World Endurance Championship (WEC) in the LMDh category. Its nomenclature derives from Acura Racing eXperimental, generation 6.
Acura Motorsports programs have been integral to the Acura brand since its launch in 1986. It previously campaigned the ARX-05 DPi in the IMSA WeatherTech SportsCar Championship and won the team, manufacturer, and driver championships in 2019 and 2020. It also won the Rolex 24 at Daytona in 2021 and ’22, including a 1-2 finish at the 2022 twice-around-the-clock endurance classic. The exterior styling of the ARX-06 prototype race car was led by the Acura Design Studio in Los Angeles, Calif., in conjunction with Honda Performance Development and ORECA.
Engine supplier for ARX-06, HPD, has a rich heritage of creating, manufacturing, and supporting Honda Racing and Acura Motorsports customers since 1993. It leads all of Honda and Acura’s high-performance racing programs in North America and specialises in the design and development of powertrain, chassis, electronics, and technology and race support. HPD delivers parts and race support to Honda and Acura amateur and professional motorsports racers and is expanding its palette of racing programs to make Honda racing products available to all racing disciplines, from karting and Quarter Midgets to the highest levels of professional racing.
Honda Performance Development built an all-new, 2.4-litre, twin-turbo engine for its ARX-06 LMDh. Regarding the choice to produce this engine, HPD president and technical director David Salters said, ‘We have some brilliant vehicle dynamicists, and we did a lot of simulations to understand what we needed. We already had a nice DPi engine, so the easy choice would have been to use the DPi engine, except it’s heavier and bigger. We thought we could do better, though. We read the rule book a lot to work out what was required to make the best car. The point of making the decision on the engine came over Christmas 2021.
‘When you start something like this, you ask how do you make the best racecar that you can? You make the lightest, most compact racecar you can and you start with the basics – make it light and close to the ground. There’s still a lot to be said for that. With the 2.4-litre V6 engine we went for, the question was can we make the power while also making it survive? We sent all the groups off to figure out what was their best thing, and then we sat down, had a three-hour meeting and decided we would use this engine.’ one of our simulation guys went away and simulated how to make the power with the combustion loads low, so he worked all Christmas and came back on the 2nd of January [2022] with a 100-page report.
‘We then set the guys off to do the best packaging, in the most compact way we can.’
HPD also did all the software for the AR-06. Salters noted, ‘We do that all in house, and we do our own software, so we do the powertrain control, hybrid control, energy management and vehicle control, brake-by-wire system and we have an in-house group that sorts all that out. We also have a vehicle dynamics group, so we have our own Driver-In-the-Loop simulator, so it goes through DIL, then HIL, then here, we write code in the truck. We are encouraged to do that. that is the lovely bit about working for Honda.’