Audi's two-time Le Mans 24 Hours winner Benoit Treluyer believes that the equivalency formula between front-wheel and rear-wheel hybrid systems has given Toyota an advantage and that the rules should be changed.
Toyota uses a super capacitor-based system on its V8 petrol-engined TS030 that sends regenerated power to the rear wheels, while Audi operates a flywheel in the e-tron quattro that powers the R18's front wheels and gives the car its boost only when it reaches speeds above 120 km/h (through regulation).
Hybrids are only allowed to activate after specified braking zones on a given circuit.
In the early stages of last weekend's Le Mans race, Treluyer engaged in an absorbing wheel-to-wheel battle for the lead with Nicolas Lapierre's Toyota, eventually losing out to his countryman - though the scrap was cut short when the safety car was deployed to deal with Anthony Davidson's accident.
And though the race-winner said he enjoyed racing with Lapierre, afterwards he said he felt it was an unfair fight.
"It was cool, I like that kind of fight and it was important to keep the advantage on them," Treluyer told AUTOSPORT. "That was the first time that I had crossed Toyota's path that weekend, I hadn't seen it on the track before then and I was surprised by the acceleration it had on the exit of the corners.
"The regulation with the hybrid systems from zero onwards for cars with hybrid power going through the rear; I think is a mistake on the regulations and they [Toyota] have a bigger advantage.
"I couldn't fight with Nicolas on the exit of corners because his hybrid system was on a lot earlier than mine. He was accelerating and coming alongside me very easily so I think they should change the regulations."
Treluyer, who shared the winning #1 car with Andre Lotterer and Marcel Fassler, was also forced to swap a stint with the Swiss driver early on Sunday morning after feeling unwell.
"I got sick because I have a throat infection, so it was just difficult to breath correctly and to drink in the car," said Treluyer. "That was the only problem."