For the first time in the history of the 911, the twin-turbo engine, now with a 3.2-litre capacity, was given water-cooled cylinder heads, in which four valves were arranged per cylinder. The cylinders remained air-cooled. The power train delivered ca. 845 hp (621 kW). In 1978 too, Porsche successfully defended its title in the one-cup world championship.

A year later, a client team’s 935 ‘K3’ won at Le Mans – and for many a year this was to remain the only overall victory by a race car based on a street-legal model. Second and third places also each went to a Porsche 935, while fourth place was taken by a 934. Thanks above all to the uniquely close cooperation with client teams, Porsche again won the one-cup world championship in 1979 and 1980. In the same years, Porsche clients took the titles in the important IMSA and TransAm championships in the USA.

The FIA Driver’s Endurance World Championship also went in 1980 and 1981 to 935 drivers. For numerous races the 935 went down in the annals as the car with the record number of wins. At Sebring alone this production race car remained unbeaten from 1978 to 1982 and won again in 1984. At Daytona the most extreme of all 911 models took overall victory from 1978 to 1983 in unbroken succession.

While the 935 gained success after success in the ‘Silhouette Formula’, the standard 911 models also demonstrated the sporting abilities of the classic cars from Stuttgart. In 1976, on the Nordschleife of the Nürburgring Fritz Müller and Herbert Hechler together with Karl-Heinz Quirin secured Porsche’s first win in the Nürburgring 24 Hours Race in a 911 Carrera RS. With further victories in the 911 in 1977 and 1978, Müller and Hechler completed the first hat-trick by any manufacturer in the history of the event, perhaps the toughest endurance race in the world.

The 935 remained in use by clients until the middle of the 1980s. The spotlight by now, however, was on a different Porsche, which was not based on the 911: when for the 1982 season the Fédération Internationale de l‘Automobile (FIA) formulated new rules for sports cars and prototypes, Porsche was already well prepared with the 956 C. The revolutionary ‘ground-effect’ prototype went on to win race after race. In Formula 1 the ‘TAG Turbo’ engine developed and built by Porsche powered a McLaren to world championship titles in 1984 and 1986. At the end of the eighties, Porsche turned its attention to motorsport in the USA, while the 962 C and 962 IMSA achieved further racing success.

Based on the 911, Porsche kept on producing small runs of competitive cars (e.g. the 911 SC RS, see above) and prototypes for motorsport. In 1986, making its very first start at Le Mans, the all-wheel drive 961 won in the IMSA/GTX class and came a very creditable seventh in the overall standings. Behind the 961 name was the 640-hp (471 kW) race version of the 959, with its pioneering technology passing here an endurance test that could scarcely be any tougher. In 1987, the works team returned to Le Mans with the 961, featuring a twin-turbo six-cylinder engine that now produced 680 hp (499 kW). Its race ended in an accident, but the driver was unhurt.