Group B, with its less strict technical specifications, probably ushered in the most innovative era in rallying: a high-tech arms race, so to speak, in which the participating teams outdid each other in their efforts to speed up development work. Even during the 1981 season, the first in which Audi participated, the quattro began to hint at its later superiority. The Finnish Hannu Mikkola won two events and came third in the drivers’ rankings, despite the teething troubles suffered by the car initially. In San Remo, the Frenchwoman Michèle Mouton became the first woman ever to win a world championship rally.
In 1982 the Ingolstadt-based motor team did justice to the technological lead claimed in the manufacturer’s slogan “Vorsprung durch Technik”. Mikkola, Mouton and their Swedish colleague Stig Blomqvist scored seven outright wins in eleven rallies, and finished the season with the manufacturers’ title and the runners-up title for Mouton in the drivers’ championship. In 1984, the long-awaited double success was achieved: Blomqvist took the driver’s title almost unchallenged, with wins in five rallies. The season had already begun with a sensational 1-2-3 victory in Monte Carlo, with Walter Röhrl, a newcomer to the team, leading his Scandinavian colleagues across the finishing line after a breathtaking duel.
During the season, however, the initially unrivalled quattro began to encounter new and vigorous competitors, for example the Peugeot 205 T 16, the first pure competition car concept with mid-engine to be seen in rallying. The temptation for Audi to pursue a similar approach was great, and a prototype was in fact built. The idea was none the less rejected because it was felt that the rally cars should not be too dissimilar to those sold to the public.
Instead of this, the Sport quattro, a 331 kW (450 bhp) front-engined car, made its debut at the end of 1984. The wheelbase was shortened dramatically, by no fewer than 32 cm, in an attempt to make the car even lighter and more agile.
The Sport quattro, as it happened, was fated not to enjoy any great successes, even in its final evolution stage, the S 1. Its technical features nonetheless earned a place in rallying history if only because of their extreme character. The officially quoted power output of the five-cylinder aluminium-block engine was 350 kW (476 bhp), but with the recirculating air system that kept the turbocharger turning over at a high speed, the true figure was probably in excess of 500 bhp at 8,000 rpm. With a moderately high final drive ratio, the S 1 (which weighed only 1,090 kilograms) could accelerate from a standstill to 100 km/h in 3.1 seconds. Some of the cars were equipped with a power-shift gearbox – a forerunner of today’s DSG technology. The car had a lattice-tube structure clad with sheet steel and plastic panels. For the sake of better weight distribution, the radiator, fan and alternator were banished to the rear of the car. Vast wings and spoilers had the task of increasing downthrust on fast sections of the route; the brakes had a water spray cooling system.
In the spring of 1986 came the end for the Group B cars with their boundary-pushing technology. Audi decided not to enter for any further events in the series. Following serious accidents, the international organising body FISA resolved to change the rules and permit only near-series Group A cars to take part. As it happened, the S 1 was able to celebrate one final triumph: in 1987 Walter Röhrl took this car with its 441 kW (600 bhp) engine up the Pikes Peak run in Colorado, USA, with its 156 bends and maximum altitude of 4,301 metres.
This victory was emulated in the following two years by Michèle Mouton and Bobby Unser, giving Audi a hat-trick in this imposing American hillclimb event, the “Race to the Clouds”. The best Audi time of 10 minutes 47.85 seconds remained unequalled for many years afterwards.