In Pixar's Cars, the racing series Lightning McQueen enters is the Piston Cup.
The Piston Cup is the fictional stock-car championship at the center of Cars. McQueen is a rookie competitor who finishes the season tied with veteran racer The King and rival Chick Hicks, leading to a decisive race in California. The championship gives the film its sports storyline while his stay in Radiator Springs supplies the personal story.
The fictional competition is strongly inspired by American stock-car racing, especially NASCAR-style oval racing. Its name is also a nod to automotive engineering, since a piston is a key moving part inside many internal-combustion engines. The Piston Cup itself is presented as a major trophy in the Cars world.
The Piston Cup should not be confused with the Dinoco sponsor or the final race at the Los Angeles International Speedway. Dinoco is a fictional company, while the Piston Cup is the championship series and trophy associated with the season.