24h Le Mans
24 HOURS CENTENARY – THE LE MANS EXCEPTION ⎮ In its 100-year history, the legend of Le Mans has been built on not only lasting technological innovation, but also on records that have wowed motorsport fans all over the world. Topping the list is the speed record in the Mulsanne Straight, held since 1988 by French constructor WM. Here is a look back at a performance called the "400 kph mission" as remembered by one of the engineers who lived it.
The Mulsanne Straight, a six-kilometre inspiration for absolute speed, has stimulated imaginations and fueled many dreams of extraordinary performance, including reaching 400 kph since the 1970s.
When the 917 first appeared in 1969, the record was already on the mind of Ferdinand Piëch, grandson of founder Ferdinand Porsche, the marque's sporting director at the time. He considered it just as important as winning, and never stopped fine-tuning the aerodynamics of the first Porsche to win at Le Mans. British driver Jackie Oliver reached a top speed of 386 kph during the free practice in 1971 and even though he "failed" by 14 kph, the record held until 11 June 1988.
Five years after Oliver's achievement, French constructor WM was created. Vincent Soulignac: "I joined WM in the summer of 1976. At the time, I had been an engineer at Peugeot's research centre in La Garenne. We did our first 24 Hours of Le Mans in 1976. At WM, we were amateurs in the truest sense of the term, none of us were salaried. We developed and entered our race cars at Le Mans as a hobby. I quickly took on the technical responsibilities and defined the entire mechanical architecture. Gérard Welter (WM co-founder with Michel Meunier, Ed.) supervised everything else and particularly the aerodynamics."
After the launch of the Group C prototypes class, Welter's focus on aerodynamics went to another level during the second half of the 1980s. "The FIA created Group C to attract constructors, which made budgets skyrocket. Around 1985-1986, we started thinking about sponsors. The Heuliez company (specialised in the transformation of road and utility vehicles, Ed.) and owner Gérard Quéveau agreed to join us in our attempts to establish a speed record at the 24 Hours of Le Mans. Heuliez then took over the #52 WM. Reaching 400 kph was a motivating endeavor for the entire team. You not only need a very low drag, but also total stability, because you don't launch one of your drivers at 400 kph without knowing what you're doing."
The WM entrusted to Heuliez underwent highly streamlined aerodynamic work. In addition to the technical requirements for a car considering such a record, one needs the proper speed measuring equipment. "You have to remember that back then, speed measurement on the roads was carried out by the Mesta 206 radar gun (built by the SFIM). They were set up trackside in the Mulsanne Straight at the 1987 and 1988 24 Hours. In 1987, no speeds were recorded above 390 kph and when the WMs passed through, the Mesta 206 failed to record any speed, even though we had reached 410 kph. The 1987 24 Hours ended without us having officially beat the speed record. We were disappointed of course, and decided to try again in 1988. So, I talked with the SFIM who agreed to supply different equipment."
Since its first appearance in the 24 Hours in 1976, WM had opted for an original PRV turbocharged V6 engine named after the association between Peugeot, Renault and Volvo for its production. That decision proved important in establishing the speed record on the triumphant day of 11 June 1988. "On Saturday night during the race, around 22:00, an engineer from the SFIM told me they had a new radar gun, the Mesta 208. I called Roger (Dorchy, one of the drivers in the #51 WM, Ed.) and asked him to put an extra 50 grams of boost pressure on the engine. After that, the car made it to 407 kph. Gérard (Welter, Ed.) and I were both working for Peugeot, and it was agreed that, given the launch of the Peugeot 405, we would declare the speed record at 405 kph."
For Dorchy's penultimate participation (he represented WM 11 times in 15 starts from 1974 to 1989), he entered the record books at the 24 Hours of Le Mans. A little more than three months after that historic 11 June 1988, at the Paris Motor Show Peugeot presented a full-scale model of the first design of its 905, which would go on to win the race in 1992 and 1993.
Could the 405 kph record be beaten one day for a perfect mix of technological innovation and pure performance ahead of the use of hydrogen at the race? Soulignac thinks anything is possible: "I believe if someone wanted to design a car for that purpose, they could beat the record in the section of the Mulsanne Straight before the first chicane, and even in what I call the third straight (between the Mulsanne and Indianapolis curves, Ed.). In fact, 400 kph is also a myth. That's 250 miles per hour...basically, round numbers are better (laughs, Ed.).”
PHOTOS (Copyright - ACO/Archives): LE MANS (SARTHE, FRANCE), CIRCUIT DES 24 HEURES, 1988 24 HOURS OF LE MANS. WM fielded two P87 prototypes in 1988 entrusted to Roger Dorchy, Claude Haldi, Pascal Pessiot and Jean-Daniel Raulet. Both cars were forced to retire, but the #51 fulfilled its mission, establishing the current Mulsanne Straight speed record.
