In 1989, Mazda began testing a four-rotor rotary engined RX-7 GTO racing car. It had a weight-to-power ratio of less than 2kg/PS, which was outstanding performance. At the 1990 season opener (the Daytona 24 Hours) with the 1989 GTO champion Pete Halsmer as lead driver, Mazda took on the likes of the Mercury Cougar XR7 and the Nissan 300ZX and secured pole position straight off the bat. The RX-7 just missed out on victory, finishing the race with an impressive second to cement an auspicious start to the season.
In 1990, following a superb debut race, the GTO class RX-7s took second place again in the following round in Miami, and third place in the Sebring 12-hours. The RX-7 remained one step away from victory with yet another second at the fourth round in Long Beach. Finally, at the raceway in Topeka, Kansas, the long-sought after first victory was secured, and Mazda followed it up with another win in the sixth race at the Mid-Ohio Sports Car Course.
At the 11th race in San Antonio, Texas, Pete Halsmer started from the outside lane of the front row. After a fierce battle with a Mercury Cougar, he claimed the RX-7’s 100th IMSA victory. It was an unprecedented feat accomplished in just 12 years of IMSA competition that had started at the 1979 Daytona 24-hour race.