IMSA and ACO: Space for both LMH and LMDh to co-exist

There is space for both LMH and LMDh to co-exist in the sportscar racing world, the presidents of the ACO and IMSA told reporters at Daytona.

When asked by MotorsportWeek.com at a press conference about Porsche motorsport boss Thomas Laudenbach’s opinion that LMDh and LMH should be merged, ACO president Pierre Fillon was emphatic that both could co-exist. “I think there is space for LMH and LMDh. We don’t have to speak now about LMH and LMDh – the convergence is strong, we have cars of the same weight, the same power, the same aerodynamics. We try to balance the cars.”

John Doonan, the president of IMSA, had a similar view to Fillon, adding that it was thanks to the ACO and IMSA’s work that the disparate cars in the two rulesets could be balanced. “A lot of credit to where we are today goes to Thierry Bouvet, technical director at the ACO, and Simon Hodgson and Matt Kurdock on our side. These gentlemen have worked themselves to the ground to make all this come together with our partners at Bosch, Williams and Xtrac,” said Doonan.

He continued: “So, to Pierre’s point, it is possible to balance both platforms. We worked collectively to make sure that as we get them both on the track, in places like Super Sebring in six weeks, that we have a very clear view of demonstrated performance, and how all these cars act. And then we can continue to try to create the best racing possible.”

36 MAKOWIECKI Frédéric (fra), GOUNON Jules (fra), MARTINS Victor (fra), Alpine Endurance Team, Alpine A424 #36, Hypercar, action during the Test Day of the 24 Hours of Le Mans 2026, 3rd round of the 2026 FIA World Endurance Championship, on June 7, 2026 on the Circuit des 24 Heures du Mans in Le Mans, France - Photo Julien Delfosse / DPPI

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Doonan also noted that both series boast a stable set of regulations. “We do have a stable rule set, and a 10-year extension to our agreement among these two organisations. We’ve given a very clear path and statement to the automakers and to the fans that we have a stable rule set. That’s really positive for everybody.”

Finally, IMSA chairman Jim France added that convergence has been a collaborative effort across the industry. “And I think we also had the support and help from the engineering groups, with the various manufacturers as we put this together with our technical committees. So it’s been an industry collaboration.”