In June of 2014, Porsche will return to Le Mans with a newly designed LMP1 racing machine. With 16 overall victories at the 24 Hours of Le Mans, the pinnacle of endurance motor racing, Porsche is the most successful manufacturer in the race’s history. Their last win, though, was back in 1998 with the 911 GT1, so Porsche has labeled this endeavor as “Our Return” and “Coming Home”.
Sports Car Digest continues its series of photo retrospectives drawn from Porsche’s Le Mans archive. After profiles of Porsche at Le Mans in the 1950s, Porsche at Le Mans from 1960 to 1968 and Porsche at Le Mans from 1969 to 1973, the fourth installment looks at Porsche’s successes from 1974 to 1981.
Porsche again wrote technological and sporting history at Le Mans in 1974. The first turbocharged race car on the Circuit des 24 Heures was the 911 Carrera RSR Turbo 2.1. Porsche prepared to tackle the Makes World Championship for production cars, now scheduled for 1975, with this brute of a 911. Its six-cylinder boxer engine, as stipulated in the regulations, was reduced to 2,142 cc and with an air-charge cooler delivered around 500 hp (368 kW). Porsche had already gained a great deal of know-how through racing the 917/10 through to the 917/30 in America with fledgling turbocharger technology for high-performance petrol engines. During the design phase of the RSR Turbo 2.1, emphasis was placed on reducing the weight in order to have at least a chance of success against the sports prototypes with their tubular frames. Hence, the safety cage was aluminium. All hoods, fender flares and doors (each weighing 2.25 kg) were made of plastic. To ensure consistent handling, Porsche took an unconventional path. The fuel tank was now located in the co-driver’s seat. On Sunday morning, Gijs van Lennep and Herbert Müller were running second behind the big favourite Matra-prototype, whilst Helmut Koinigg and Manfred Schurti were forced to park the second works-entry after 87 laps with a damaged connecting rod. The Matra then developed a gearbox problem. Porsche sent two of its best mechanics into the pits of the French. The Porsche lads repaired the gearbox of their strong rivals in a record time of 20 minutes. The Matra won. The background to this rescue operation — the gearbox of the Matra was a Porsche development project. And as they say, the customer is king. Ironically, from Sunday morning on, van Lennep and Müller had to make do with just fourth gear. A gearbox change would take too long in their production-based RSR. The first turbocharged Porsche 911 brought home a sensational second place. Several weeks after this final acid test, Porsche presented the 911 Turbo (930) with which the 911 would explore new realms of performance.
With the launch of the World Makes Championship for Production Cars postponed for a year, the works team took a break in 1975, but provided support to customers contesting Le Mans. Reinhold Joest fielded a 908/03 fitted with the long tail of the 917/30 modified specifically for Le Mans. Intermittently, Joest, Mario Casoni and Jürgen Barth were running in second with the three-litre, eight-cylinder boxer, but their dreams of a podium result were dashed when Casoni crashed and had to pit for a 60-minute repair job. Nevertheless, the private Porsche finished fourth. Positions five to eleven were locked out exclusively by 911 Carrera RSR and RS. An RSR campaigned by George Loos’ team won the GT category, while an RS fielded by Gerhard Maurer was successful amongst the production-GT cars.
In 1976 Porsche treated insiders and fans to two more Le Mans premieres. Jacky Ickx and Gijs van Lennep claimed victory in a Porsche 936 featuring the 2.1-litre boxer turbo engine, which had underlined its potential in 1974, now delivering 550 hp (405 kW). With this triumph, the Belgian and the Dutchman achieved two premieres in the Swabian racer — never had a boxer engine won here. And never with a turbocharged motor. The 936 was, in compliance with the “Group 6” technical regulations for the World Sports Car Championship, a full-blooded race car with a mid-engine and space frame and weighed just 765 kilograms.
Like the 936, the Porsche 935 celebrated a debut in Le Mans. The factory successfully deployed the (930) 911 turbo-based race car in the World Championship for Makes (Group 5). This racing-911 weighed in at 970 kilograms. At work in the rear was a 2.8-litre turbo, which Porsche specified as delivering “at least 590 hp” (434 kW). Driven by Rolf Stommelen and Manfred Schurti, the 935 also proved unstoppable and, clinching fourth overall and winning the “Group 5” classification. With further firsts in “Group 4” for near-standard race cars and in the IMSA GTX class, Porsche netted all winners’ trophies up for grabs in 1976 at Le Mans.