Leupen expressed his frustration at both the Balance of Performance changes made to the Hypercar class in the run-up to last weekend’s Test Day, made without the consent of the manufacturers, and the decision to bring back tyre warmers for Le Mans only.
Toyota was the worst-hit of the Hypercar manufacturers by the BoP adjustments, having 37kg of extra weight added to its GR010 HYBRID - something driver and team principal Kamui Kobayashi had estimated would be worth 1.2 seconds a lap around the Circuit de la Sarthe.
While the sporting regulations in the World Endurance Championship do not allow open criticism of BoP decisions, the target of Leupen’s ire was the way the changes were implemented by the FIA and the Automobile Club de l’Ouest.
Speaking prior to Ferrari taking pole position in Thursday evening’s Hyperpole session, he suggested that some of Toyota’s rivals in the Hypercar class had managed to gain an advantage from the organisers by “screaming the loudest”.
“I can’t talk about the weight [itself], but we can talk about the fact they have changed the process and the system in the middle of the game,” Leupen told Motorsport.com.
“We are of the opinion that they should have not done this. And if they had to do this, not in the way they have done it. We would like to have these things not happening again.
“Of course there is pressure [on the organisers], it’s not nice that if you just started a programme you cannot win immediately. But there is some logic to this.
“From our point of view, the logic is not to scream the loudest and get something. The logic is that we have been working hard for a long time, and this is more or less nullified.
“It seems now that if you scream loud enough, something is changed to your advantage. We are very unhappy with this process.”
Leupen also questioned the decision to bring back tyre warmers for Le Mans after tyre pre-heating had been banned at the start of the 2023 WEC campaign.
“We don’t feel comfortable with this kind of thing, if you know how a company like us is working on and reacting to these things,” he said. “It doesn’t make us feel good.”
Toyota Gazoo Racing Europe technical director Pascal Vasselon confirmed that the team had not run on this year’s Michelin tyres with normal tyre warmer use prior to last weekend's Test Day.
He clarified that the squad’s traditional pre-Le Mans shakedown at Spa was undertaken using demonstration tyres, while also conceding that Toyota used some pre-heating during its winter test programme in very low temperatures.
“We mitigated a bit according to the circumstances,” said Vasselon. “We were running at four degrees of track temperatures in winter, so we put some temperature in the tyres just to make sure they were alive.
“But we never tested like we are running the tyres [at Le Mans].”
