The PC-20 was powered by an Ilmor-Chevrolet V8 265A turbo engine and it debuted at the 1991 Gold Coast IndyCar Grand Prix where it qualified 6th and 7th with Fittipaldi and Mears, respectively. In the race Mears scored a 3rd place, while Fittipaldi retired with drive shaft failure. After a 4th place finish in Long Beach with Mears, and a 3rd place finish at Phoenix with Fittipaldi, the PC-20 scored its biggest win at 1991 Indianapolis 500. In qualifying, Mears clinched his 6th pole at Indy 500 (224.113 mph). Mears battled with Michael Andretti during final stages of the race, who led Rick Mears by 15 seconds when a caution flag flies on lap 182. Andretti was able to make it to the pits for fuel under the yellow, while Mears lined up as the leader. Andretti then completed a daring pass around the outside of Mears into turn 1 on the restart. Exactly one lap later, Mears repeated the move on Andretti, passing him on the outside of turn one to re-take the lead. Another caution does not alter the result as Mears powered away again to his record-tying fourth Indianapolis 500 Victory, tying A.J Foyt and Al Unser, Sr. During the rest of the season, the Penskes weren't able to compete with Michael Andretti dominance, who clinched the title with 8 season wins. Nevertheless, Fittipaldi won at Detroit, and Mears scored a win at Michigan 500, as confirmation of the PC-20's competitive form on long ovals.