Ken Block is working with Audi on electric vehicles, so he took advantage of that new partnership by raiding the automaker's secret stash of race cars and prototypes.

During a trip to the automaker's headquarters in Ingolstadt, Germany, Block toured the Audi Tradition heritage collection and drove two very special cars: a Group B Sport Quattro S1 E2 raced by Walter Röhrl, and the once-secret Group S prototype.

As a refresher, the original Audi Quattro brought all-wheel drive to the World Rally Championship (WRC), initially dominating the series. But the box-flared Audi was soon surpassed by Group B machinery from Lancia and Peugeot. So Audi created the short-wheelbase Sport Quattro, and continued developing it until Group B was eliminated entirely after the 1986 season.

The  Audi Quattro S1 E2 that Block drove in the video was a dream come true for him, as it's one of the cars that got him interested in rally racing in the first place.

Ken Block drives Walter Röhrl's Audi Sport Quattro S1 E2

Ken Block drives Walter Röhrl's Audi Sport Quattro S1 E2

The Group S prototype was supposed to be what came after the Sport Quattro. Audi's engineers kept the turbocharged inline-5 engine, but placed it in a mid-engined chassis not based on any production model. At least one prototype was built using S1 bodywork, but it was withdrawn after it was spotted during testing.

Audi built multiple prototypes with complete Group S bodywork, according to a 2016 Road & Track story, but most were crushed after the Group S category was canceled. The sole survivor was hidden by a sympathetic Audi staffer, and wasn't shown to the public until 2016. Before Block, Audi reckoned only five people had driven it.

Block and Audi recently announced a partnership for electric vehicle projects, but it's unclear exactly what that partnership will produce. At the end of the video, Block got behind the wheel of the 2022 Audi E-Tron GT and drifted it around the Audi Quattro racer. A teaser at the end of the video also suggested that Block will drive more cars from the Audi Tradition collection.

Check out the full video to see Block hoon these extremely rare internal-combustion rally cars on a German airfield and to learn more about their history.