90 IMSA GTO
Following the 200 Trans Am quattros used in 1988, Audi chose to enter the IMSA GTO series. It was a silouette (regarding roof and pillars) class of seriesproductioned cars, but was unlimited in any other ways.
Audi took their Audi 90 quattro as a basis, keeping the roof and building a spaceframe-chassis out of steel with carbonfibre bodyparts. Gigantic flares tucked the enormous 14J17 wheels, and the boot had two versions of racing spoilers. Coupe was also protected by aluminium-panels. The fuelcell was of rubber, packed in aluminium and mounted in the rear of these cars to keep things safe. Naturally, the quattro drivetrain was used, much with the same specifications as the last Group B cars with sixspeed gearboxes. The 90 IMSA GTO appreared in the usual Audi Sport livery.
Yet again, the turbocharged inline five was taken to racing, but this time in it’s 20 valved featuring Bosch enginemanagement. Most noticeable is the similarity to the engine design that of the Sport Quattro S1, now offering 720~730 hp and 850 Nm on the 2190 ccm. with plenum etc optimized for racing and an engine compartment which is far less restrictive than in a small(er) rallycar
Length & width given by 4480 mm & 2000 mm, with a weight of 1206 kg.
Hurley Haywood and Hans Joachim Stuck was chosen as drivers, whereas the latter won at Summit Point, Mid-Ohio, Topeka, Sears Point, Glen Watkins, Lime Rock and Laguna Seca. The drivers achieved 3rd and 4th place (in that order) in the championship, while Audi took 2nd place in the constructor championship.
‘Audi quattro’, Laurence Meredith
‘The Audi quattro book’, Dave Pollard