Audi’s brutal IMSA GTO car didn’t begin in IMSA at all. Rather, the lunatic German began its career in Trans-Am racing in 1988. Audi was just coming off a scandal involving unintended acceleration in their road cars and decided to go racing to demonstrate their ability to build a car that was terrifying for all the right reasons. The car they turned up with contained the engine and running gear from that legend of legends, the Group B Ur-Quattro. Around this they built a custom space frame and covered it all in carbon fibre. Wide carbon fibre. The only panel it shared with the road-going Audi 90 was its roof.
In Trans-Am trim, the 90 Quattro produced 510 bhp from its 2.1 litre turbocharged 5 cylinder engine. It won 8 of the 13 races it was entered in and helped Hurley Haywood to claim the driver’s championship that year. Trans-Am reacted by banning all wheel drive cars so Audi became a factory-backed team racing in the more technologically adventurous IMSA GT Championship. Here, a bigger turbocharger allowed the car to produce a ludicrous 720 horsepower. With an engine sitting mostly ahead of the front axle and an exhaust exiting through the passenger door, Audi claimed victory in 7 of the 13 races they entered.
The works team would have surely won the constructors’ championship that year, but for missing the first two races of the season and retiring from the third. The 90 Quattro IMSA GTO would prove to be a brilliant flash in the pan, as the bigwigs in Germany decided to concentrate their motorsport efforts on the DTM championship at home and pulled support for the IMSA team. Despite only racing for two years, the car became a cult favourite. Driver Hans-Joachim Stuck recalled the Americans sneering at this German saloon car turning up to race with a tiny engine, and would frequently start to yodel in celebration as he crossed the line to take the chequered flag.