Over time they became increasingly involved in this activity and in 1976 made their debut at Le Mans with a GTP car (a closed-body sports prototype) powered by an elaborate version of the Peugeot PRV.

[3] For this Welter and Meunier changed their programs after the 1986 edition of the French marathon, concentrating their efforts and their limited economic resources on a new and emblematic goal: to overcome the 400 km/h barrier on the Hunaudières straight.

[4] Starting from the 1986 car, for the WM P87 the aluminium monocoque chassis with a central reinforcement beam, somewhat conventional, was modified, adding box-like structures in the nose and sides to be able to support the new bodywork, which was significantly wider than the previous one.

The bodywork was modelled in the Peugeot wind tunnel, which also supplied the engine, where the team carried out tests on Sunday over a period of four months: the resulting shape had an increased width, which covered the wheels and greatly reduced the aerodynamic resistance and a better solution were found for the flow of fresh air to the intercoolers of the two turbochargers, by means of pipes that passed from the nose under the front suspension.

As permitted by the Group C regulations, the car exploited the ground effect to generate downforce and the P87 saw the wheelbase and Venturi channels lengthened compared to the model that preceded it, in order to improve aerodynamic efficiency.

[7] In the race, the car was plagued, like many other competitors, by poor-quality fuel which damaged the engine and forced it to retire, while it had already been detected by the ACO speed detectors at 381 km/h, although the team claimed to have hit the target, on the basis of surveys made with their own means.