The Automobile Club de l’Ouest and IMSA have unveiled the amended technical regulations that will allow LMH and LMDh to race alongside each other in the FIA World Endurance Championship and IMSA WeatherTech Sportscar Championship in 2023.
Additionally, it has been confirmed that cars built under the Le Mans Hypercar regulations will be able to compete in the IMSA championship, something that had not been previously confirmed.
The changes were first confirmed by the FIA World Motor Sport Council after their meeting on Thursday, although details were not yet available at the time.
The details have now been released by the governing bodies and specifically focus on four key areas: tire fitment, acceleration profile, braking capability and aerodynamics.
Under the new rules, all-wheel drive (AWD) cars will have a 31-inch tyre profile at the front and the rear, , while cars with rear wheel drive (RWD) will have a 29-inch profile at the front and a 34-inch profile at the rear.
Key changes have also been made to the acceleration profile. For the AWD cars, activation speed deployment will become a Balance of Performance tool as opposed to something defined in the technical regulations.
Furthermore, due to track variations in global competition, there will be two BOP activation speeds corresponding to track conditions, depending on if a wet or a dry tyre has been fitted to the car, likely between 120 and 160 kilometers an hour.
LMDh cars will receive control software to limit the contribution of the electric motor to traction control capability.
In terms of braking capability, both RWD and AWD cars will have identical coasting capabilities, with the torque levels from the front and rear axles taken into account for AWD cars. Additionally, the front axle on AWD cars will be fitted with a zero-lock mechanism, which will be activated on coasting.
Finally, both parties have outlined rules for aero homologation. All LMH cars will continue to undergo wind tunnel testing at the Sauber facility in Switzerland to be homologated for the WEC.
However, if a Hypercar competitor wishes for its car to be homologated for IMSA competition, it must undergo a separate procedure at the Windshear facility in Concord, North Carolina.
The same applies in opposite for LMDh machinery, with domestic homologation taking place in North Carolina, but WEC homologation required to be passed in Switzerland.
“This major announcement stems from our ambition to forge a common future for Endurance racing,” said Pierre Fillon, President of the Automobile Club de l’Ouest. “We have all worked together to achieve this landmark agreement and I would like to thank all the stakeholders very sincerely.
“It is wonderful news for teams and fans alike and maps out a bright future for Endurance. The manufacturers dreamed of being able to participate in the greatest endurance races in the world with the same model of a car: this will now be reality.”
IMSA president John Doonan added: “What we achieved as a group a few weeks ago in Paris has the potential to revolutionize prototype sports car racing all over the world. The stage is set for a highly competitive top category that will include many of the world’s greatest automotive manufacturers, showcasing relevant technology in the world’s most prestigious endurance races.
“Collectively, we have an opportunity to engage with the next generation of endurance sports car racing fans and elevate our sport to the highest levels. I cannot be prouder of the spirit of collaboration between our IMSA team, our colleagues at the ACO and FIA, and all of our automotive partners.”
