Onroak Automotive is pushing to have a revised low-downforce aero kit approved for its Ligier JS P217 Gibson ahead of the 24 Hours of Le Mans, following a top speed deficit for the LMP2 car at the official test day.

Sportscar365 has learned that the French constructor has proposed changes to its already homologated low-downforce Le Mans aero kit, after being up to 20 km/h slower in trap speeds than the competition in the new-look class.

It’s understood one car, believed to be the No. 32 United Autosports entry, tested a yet-to-be-approved aero update in last weekend’s test day, aimed to improve top speed.

The Anglo-American team was the quickest Ligier in the speed traps, posting a 333.9 km/h top speed compared to the pace-setting LMP2 Dallara P217 Gibson at 341.3 km/h, which was the quickest overall at the test.

Discussions have taken place between the FIA and ACO, with Onroak asking for the change to be outside of the category’s one permitted “joker” performance update in each LMP2 car’s four-year homologation period.

“We want to change, to improve the top speed,” Onroak President Jacques Nicolet told Sportscar365. “We asked, but for the moment we don’t have the answer.”

When asked about a potential change, less than three days before the start of Free Practice on Wednesday, ACO Sporting Director Vincent Beaumsenil declined comment.

“You can have one update in the period of four years, subject to different criteria,” Beaumesnil said. “But the rules are public, you can just look at it.”

Onroak team principal Philippe Dumas, meanwhile, admitted that it would be “just impossible” to claim LMP2 class honors without any changes made, due to the domination of the Oreca 07 Gibson, which swept the top 13 positions at the test day.

“Unless [all of] the 15 Orecas have reliability issues, it would be impossible,” he told Sportscar365.

Dumas believes the gap in performance between the Oreca and the other three LMP2 constructors is primarily due to the constructor’s Le Mans aero kit, which he alleges was developed with Oreca’s LMP1 experience.

An ORECA spokesperson told Sportscar365 this is not correct.

“They were focussed on the aero side, and they had all the valuable information because it is the same car [as the Rebellion R-One] to be honest, and they have all of the Toyota resources in Cologne,” he said.

“They built an amazing car… That’s a high compliment, to be honest. I think Oreca did an amazing job, but [the ACO] allowed Oreca to use this 05 [last year] was an incredible advantage. It’s true.

“So we are pushing to get at least something. You know that you have a joker for the four years, [but] at least to get something to be closer at Le Mans without this joker would be something.

“I think it would be fair to have this realization from the ACO and the FIA.”

Karun Chandhok, who is set for his fifth Le Mans start in the No. 34 Tockwith Motorsport Ligier, said Onroak’s proposed update would be a “good step forward” and the only way to take the fight to the dozen-plus Orecas in the race.

“The Orecas are otherwise in a different race and I think that they need to think about the show a little bit.

“I know they’ve got 13, 14 cars, whatever it is, but part of sports car racing is having different manufacturers always competing.

“If you’ve got one that’s so far ahead of the others, it’s not much fun for the show, it’s not much fun for the people who aren’t in an Oreca.”

Luke Smith contributed to this report