![](https://upload.wikimedia.org/wikipedia/commons/thumb/9/98/1973_Datsun_240Z_GTU_racer_no._33%2C_front_right.jpg/220px-1973_Datsun_240Z_GTU_racer_no._33%2C_front_right.jpg)
Grand Touring Under (GTU) is the name of a former classification designated to grand touring cars competing in sports car racing, originally used by IMSA in the IMSA GT Championship,[1] and later by Grand-Am in the Rolex Sports Car Series.[2] IMSA used the class between 1971 and 1994, and Grand-Am used the class for a single season in 2000.[3] The original class rules specified an engine displacement of under 2.5 L (150 cu in), natural aspiration, and was the secondary class below the top tier class, GTO. The class later became known as GTS-2 in 1995, then GTS-3 between 1996 and 1997, and eventually evolved into the GT3 class for 1998.[4][5]
References
[edit]- ^ "IMSA Archives - International Motor Racing Research Center". www.racingarchives.org.
- ^ Quiniou, Louis (March 14, 2016). "#Focus – The IMSA GT Championship Story".
- ^ "An introduction to the IMSA GT Championship (part 1) #blogpost". Car Throttle. 2 August 2016.
- ^ "The Story of Mazda's Success in the IMSA GT Championship". Car Throttle. 16 January 2017.
- ^ "IMSA GTU Division Featured Close Competition". May 26, 2016.