With 710bhp and so much grip it could bend physics, the 90 quattro GTO was the stuff of nightmares for Audi’s IMSA rivals
Hans-Joachim Stuck – he of the hair, the speed and the slow-down-lap victory yodelling – is on record as saying the Audi 90 quattro IMSA GTO is his second favourite race car of all time. When you consider his favourite is the Le Mans-winning Porsche 962, and that he makes no mention of his Formula 1 or DTM drives, you realise just how special this most un-Audi Audi was.
‘It was kind of on the upper edge of a regular chassis car, the maximum you could do with a street car,’ recalls Stuck. That “upper edge’ meant taking the Audi 90 – itself a high-spec Audi 80 with a five-cylinder engine and quattro all-wheel drive – and replacing the, erm, entire monocoque with a tubular spaceframe, adding a composite body with arches that make Alexis Carrington’s shoulder pads look modest, and dropping in the unhinged Audi quattro E1 S2 rally car’s engine tuned from 600bhp to around 710bhp. Only the production car’s wheelbase and roof were retained.
Four-wheel drifting over kerbs, the IMSA GTO spat flames from a sawn-off exhaust exiting through the passenger-side ‘door’ as its KKK turbocharger made a racket that sounded more Star Wars X-Wing than race car. Definitely “upper edge’.
Debuting in 1989, the IMSA GTO arrived at a crucial juncture in Audi’s history. Audi Sport had proved the quattro concept with rally titles and records at Pikes Peak. But the results weren’t so great on tarmac. Audi sales had also plummeted in the US in the wake of the long-since debunked unintended-acceleration myth. Translating the quattro success story to some totally intended acceleration on North American race circuits made sense.
The first move was a 200 quattro. When it won in its debut season, Trans Am banned it plus – with Trumponian brilliance – engines of un-American heritage. Audi moved to the 1MSA touring car series, where the GTO would face Mustangs, Corvettes and Nissan 300ZXs.
‘When we first came to the US, no-one could believe what we could achieve with this car – a small engine, five-cylinder… it’s a German saloon car!’ remembers Stuck. ‘The V8s had a little more torque but the five-cylinder was a jewel: lighter, more compact and you could use the power instantly. With the lighter engine, our braking point was later. They passed us on the straights, we passed them under braking. There was an ideal line all the others would take but we could regularly use any line!’
Audi missed the first two rounds but won more races than any rival, with seven victories – five of them one-twos – to finish the season second-in-class. The 1990 title was there for the taking but Audi US pulled the plug, killing off many enthusiasts’ all-time favourite race car (current Audi design boss Marc Lichte among them). And Hans Stuck’s second-favourite.