Grand Touring Over (GTO)[1] is the name of a former classification designated to grand touring cars competing in sports car racing, originally by IMSA in the IMSA GT Championship, and later by Grand-Am in the Rolex Sports Car Series. IMSA used the class between 1971 and 1991,[2] and Grand-Am used the class for a single season in 2000. The class had its origins in the original "TO" class used by the SCCA in the Trans-Am series, and was also similarly modeled to the FIA's Group 4 and Group 5 racing classes, but eventually evolved over time into its own category.[3] The class specified an engine displacement of more than 2.5 L (150 cu in), with engine design and number of cylinders being unrestricted. turbocharging and supercharging was allowed on engines up to a size of 6.0 L (370 cu in). Engines over 6.0 L (370 cu in) were required to be naturally aspirated. The original class became known as Grand Touring Supreme (GTS) in 1992.[4]

IMSA GTO cars at Road Atlanta in 1981

References edit

  1. ^ https://alex62.typepad.com/imsablog/2006/01/do_you_want_to_.html
  2. ^ "IMSA Archives - International Motor Racing Research Center".
  3. ^ "#Focus – the IMSA GT Championship Story". 14 March 2016.
  4. ^ "An introduction to the IMSA GT Championship (Part 1) #blogpost | CarThrottle". 2 August 2016.