 Jaguar were approached by racing team owner Tom Walkinshaw and encouraged to enter the Jaguar XJS into the 1981 European Touring Car Championship ; they succeeded in winning the competition in 1984 . Jaguar had started to provide factory support to racing team Group 44 Racing , who were using the Jaguar @-@ engined XJR @-@ 5 in the IMSA GT Championship , supplying V12 engines from 1983 onwards and supporting a Le Mans entry in 1984 . Tom Walkinshaw and Jaguar agreed to entering the FIA Group C World Sportscar Championship and developed the XJR @-@ 6 , which was powered by the Jaguar V12 engine ; the car was launched during the 1985 season . 
