In 2016 an extended sprint format series was added as a standalone championship in addition to its existing Sprint format racing series. SprintX races are 60 minutes in length and feature mandatory driver and tire changes.[1]
For 2021 the original single-driver Sprint races (which ran alongside SprintX) were moved into the multiclass GT America series,[2] which means all GT4 America races preserved the two-driver 60-minute format but dropped the SprintX name.
GT4 East & GT4 West
Beginning in 2019, GT4 America began two regional series integrated into its Sprint X Championship. The regional series consist of five rounds each in the eastern and western sides of North America in a two-driver, pro-am format.