In Pixar's Cars, the top racers compete to win the Piston Cup.
The Piston Cup is the championship prize at the center of the film's opening and closing races. Lightning McQueen, Chick Hicks, and Strip Weathers, known as The King, finish the season tied and must compete in a decisive race.
McQueen initially focuses almost entirely on winning the trophy. His time in Radiator Springs changes that attitude, and the final race shows him choosing sportsmanship over an easy victory. The cup therefore represents both athletic success and the values McQueen learns during the story.
The fictional Piston Cup racing series is modeled on American stock-car competition, particularly NASCAR. The name also echoes the automotive theme of the film. In Cars 3, the Piston Cup remains the championship McQueen and the younger racers are trying to win.