We arrive at a hairpin and Blomqvist tugs at the handbrake as the Audi pirouettes about its nose. It's fascinating to watch him in action. There is no sense of drama, just a calm authority and a method of movement. Out of the hairpin, he pumps the clutch to keep the engine spinning near its powerband. It's a boy's own anti-lag system, to replace the original system that's no longer connected to this museum piece.
That original system was one of the most brutally effective pieces of engineering ever employed in professional motorsport. Audi engineers knew they needed to keep the turbo spinning but they lacked the electronic trickery of today. They developed a crude, purely mechanical system that injected raw fuel into the exhaust manifold-a caveman approach with essentially the same result as today's systems. That's why an S1 at flat chat could be seen throwing six-foot flames out of its exhaust pipes.
The introduction of primitive four-wheel-drive systems also required the drivers to develop new techniques. Lacking the active differentials of today's cars, the early quattros understeered horribly, which made left-foot braking a must. Blomqvist was one of the early pioneers of the technique of using the throttle and brake together, which balanced the car and helped it turn into the corner.
He's employing it today and it's fascinating to watch his left foot as it jumps from clutch to brake and back again. Mikhail Baryshnikov is no more agile.
"Today's cars are easier to drive because you have so many electronics helping you," he says. "If you put the modern drivers into one of these cars, some would cope, but others would be totally lost."
The engine is angry now and the S1 never seems to be pointing in a straight line. For the amateur, this would be calamitous, but Blomqvist uses the car's inertia to swing us from bend to bend.
The ferocity of these vehicles made crashes inevitable and the Group B era came to an abrupt end when the cars were banned after two serious accidents, the second of which killed Lancia legend Henri Toivonen and his co-driver.
"It was really bad luck that the accidents happened," reckons Blomqvist. "I wasn't concerned for my safety and I don't think it was necessary to ban the cars. Today, the corner speeds are much higher, so the accidents are even bigger."
We cruise to a halt and step out of the car to be greeted by Gumpert, the man responsible for the development of the first four-wheel-drive quattro.
"We developed a four-wheel-drive, off-road vehicle for the German army in 1976," he recalls. "And when we went winter testing, I found that I could keep up with much more powerful cars. I convinced my boss that we ought to build a prototype four-wheel-drive car."
The first quattro road car was unveiled at the Geneva Auto Show in 1980 and the rally car followed a year later.
"When we originally tried to have the car homologated for competition use, the organizers thought it was a joke," recalls Gumpert. "But we won the second rally we entered." It was the start of a period of domination that would last until 1985, by which time everyone was using four-wheel drive.
Audi has now sold more than 2,000,000 quattros worldwide and the concept is critical to its brand image. And the S1, as the most extreme expression of the concept, is crucial to its history. There will probably never be another rally car quite as barking mad as the S1, which made a ride in it even more special.