In Pixar’s Cars, the opening race is called the Dinoco 400.
The race takes place at the Motor Speedway of the South and is the decisive event in the Piston Cup season. Lightning McQueen, Chick Hicks, and Strip “The King” Weathers finish together, creating an unusual three-way tie for the championship.
Because the race is shown at the start of the film, it establishes Lightning’s ambition and his rivalry with Chick. It also introduces Dinoco, the highly desirable sponsor associated with The King. Lightning’s desperation to reach the tiebreaker causes him to make a serious mistake: he refuses to let his team replace his worn tires during the race.
The Dinoco 400 is fictional, but its presentation draws on American stock-car racing. The name should not be confused with the Piston Cup itself, which is the championship trophy rather than the race. The film later returns to the racing world for the final championship event.