The Piston Cup is the fictional racing series in which Lightning McQueen competes throughout Pixar's Cars.
In the first film, McQueen is a rookie racing for the Piston Cup and is determined to win the championship. His failure to manage the final race leads to a three-way tie with veteran Strip Weathers, known as The King, and rival Chick Hicks. A final race is then held to decide the winner.
The Piston Cup is modeled on American stock-car racing, especially NASCAR. Its name also echoes the idea of an engine piston, fitting the vehicle-centered world of the films. The fictional competition provides the sporting framework for McQueen's rise, setbacks, and later transition into a mentor.
The World Grand Prix is a separate international event featured in Cars 2. Dinoco is a fictional sponsor rather than the name of a racing series, while the Dinoco 400 is a race associated with the Piston Cup setting.