competition. Can-Am Porsche Between 1971 and 1972, Penske Racing (along with Donohue as the primary test and development driver) was commissioned by Porsche to help develop the 917-10 to compete in the Can-Am series. During testing at Road Atlanta, Donohue recommended larger brake ducts, believing that more cooling would slow the brakes' degradation during a race. The Porsche engineers obliged, but the new ducts interfered with the bodywork closure pins that attached body panels to the car. Coming out of turn seven at about , the rear bodywork flew off the car, which became extremely unstable, lifted off the ground, and tumbled down the track. The front of the car was torn away, leaving Donohue, still strapped to his safety seat, with his legs dangling outside the car. Amazingly, Donohue only suffered an internal derangement of his knee with meniscus damage and limited cruciate plus collateral ligament damage. (He was operated on at Piedmont Hospital in Atlanta by Drs. J. Funk and J. L. Watts.) George Follmer, Donohue's old Trans-Am teammate, took over testing the 917-10 for Donohue, who said: Porsche, Penske, and Donohue quickly started the development of the 917-30, complete with a reworked aerodynamic "Paris" body and a 5.4-liter turbocharged flat-12 engine whose output could be adjusted from about 1,100 to 1,500 bhp by turning a boost knob in the cockpit. During the development of this motor, the German Porsche engineers often asked Donohue if the motor finally had enough power. He answered, "It will never have enough power until I can spin the wheels at the end of the straightaway in high gear." On August 9, 1975, Donohue drove the 917–30 to a world closed-course speed record at the Talladega Superspeedway in Talladega, Alabama. His average speed around the high-banked oval was . Donohue held the record for 11 years, until it was broken by Rick Mears at Michigan International Speedway. The 917-30 is referred to as the "Can-Am killer" as it dominated the competition, winning all but two races of the 1973 Can-Am championship (which is an untrue statement, because OPEC killed the Can-Am series in 1975–1976). After the Arab oil embargo in 1973, it led the SCCA, IMSA and other race series to impose fuel limitations on motor sport racing as a whole, which hampered the performance of the 917/30, making it uncompetitive in the Can-Am series. Brian Redman drove it once in 1974, and