What is Pixar's Cars franchise's racing championship called?

The racing championship in Pixar's Cars franchise is called the Piston Cup.

The Piston Cup is the central stock-car racing competition in the first Cars film. Lightning McQueen competes for the championship alongside veteran racer Strip “The King” Weathers and rival Chick Hicks. Because the championship finale ends in an unusual three-car finish, the film gives its conclusion a distinctive twist rather than presenting a routine victory ceremony.

The name is a playful reference to piston engines, whose pistons move inside cylinders to produce power. The fictional competition also echoes real American stock-car series, particularly NASCAR-style oval racing, without being an exact depiction of one real championship.

Cars 2 shifts much of its attention to the international World Grand Prix, but the Piston Cup remains important to Lightning's identity. Cars 3 returns more directly to the championship world as newer racers challenge his place in the sport.