that was it for the car as far as Penske campaigning it. The 917/30 generally is considered one of the most powerful and most dominant racing machines ever created. First IROC champion Donohue raced in the inaugural IROC series in 1973–74, racing identical, specially-prepared Porsche RSRs. In the four-race series, Donohue won the first and third of three races at Riverside and the final race of the year at Daytona. The only person to beat Donohue was his former Penske Trans-Am teammate, George Follmer. In winning the first IROC championship, Donohue beat the best racing drivers of that era from all of the major championships, such as Denny Hulme, Richard Petty, A. J. Foyt, Emerson Fittipaldi, Bobby Allison, David Pearson, Peter Revson, Bobby Unser, and Gordon Johncock. Retirement and Formula One The pressures of racing and designing the car took their toll on Donohue. By 1973, the "Captain Nice" nickname he had earned earlier in his career was being supplanted by the nickname "Dark Monohue". Donohue announced that he would retire from racing after the 1973 Can-Am season. In addition, the horrific events at the 1973 Indianapolis 500 and the subsequent death of his friend, Swede Savage, pushed him to quit. His retirement was short-lived, however, as he was lured back to full-time competitive driving by Penske when he formed a Formula One team, Penske Cars Ltd, to compete in the final two events of the 1974 Formula One World Championship, and to continue competing in 1975 with the new Penske PC1. Donohue previously had debuted in Formula One on September 19, 1971, with a Penske-sponsored McLaren at the Canadian Grand Prix at Mosport Park, finishing on the podium in third place. After coming out of retirement with his former boss, Penske, Donohue returned to Formula One, entering into the final two races of the 1974 Formula One season. Donohue finished in 12th place at the Canadian Grand Prix, but failed to finish at the United States Grand Prix. A full season of racing for the 1975 Formula One season was planned. The 1975 season turned out to be a difficult one for Donohue and Penske. Donohue was able to muster fifth-place finishes at the Swedish Grand Prix and the British Grand Prix, but the new Penske PC1 chassis proved problematic, as evidenced by three retirements in the first six races. At the Austrian Grand Prix, Donohue's career, along with