The racing competition at the center of Pixar's Cars is the Piston Cup.
The Piston Cup is a fictional stock-car championship modeled partly on American motorsports, especially NASCAR. In the first Cars film, Lightning McQueen is a rookie contender competing for the season title against veteran racer Strip Weathers and rival Chick Hicks.
The championship's final race creates the film's main conflict. Lightning misses the direct trip to California after becoming stranded in Radiator Springs, where the town's residents teach him lessons that change his priorities.
The Piston Cup should not be confused with the World Grand Prix in Cars 2, an international racing event organized around a clean alternative fuel. Dinoco is a fictional sponsor and brand within the films, not the name of the championship itself.