 TWR took over the IMSA GT Championship operation in 1988 and one model – Jaguar XJR @-@ 9 – was launched to compete in both series . The XJR @-@ 9 , which retained the Jaguar V12 engine , went on to win the 1988 24 Hours of Le Mans and World Sportscar Championship in the same year . The poor fuel consumption of the Jaguar V12 combined with new rules restricting refueling during races forced the replacement of the V12 engine in the XJR @-@ 9s successors , the XJR @-@ 10 and XJR @-@ 11 . The normally @-@ aspirated Austin Rover V64V engine , designed for the MG Metro 6R4 had recently been made redundant thanks to the Group B rally ban in 1987 , and the design rights were for sale . The compact , lightweight and fuel efficient nature of the small @-@ displacement , turbocharged engine was investigated by TWR , who considered it an ideal basis for a new engine to power the XJR @-@ 10 and purchased the design rights from Austin Rover Group . 
