Following TWR's success with the Jaguar XJS in the European Touring Car Championship, Jaguar recruited Tom Walkinshaw Racing to develop a Group C contender. Designer Tony Southgate drew on his prior work with the Ford C100 to produce a car featuring a carbon-fibre monocoque with ground-effect venturi tunnels — a construction approach that was considered revolutionary within Group C at the time.
Power came from a Jaguar V12 engine enlarged to 6.2 litres and fitted with a TWR/Zytec fuel-injection system developing 660 bhp. Suspension at both ends used double wishbones, with push-rod-activated coil springs over dampers at the front and magnesium uprights with coil springs over dampers at the rear. The XJR-6 name followed the same numbering style as Bob Tullius' Group 44 IMSA GTP Jaguars, though the two programmes were entirely independent of one another.
The XJR-6 made its competitive debut late in the 1985 season at the 1000 Kilometres of Mosport in Canada. TWR entered two cars; they qualified third and fifth on the grid. One car retired after just 12 laps with a failed wheel bearing. The second, driven by Martin Brundle, Mike Thackwell, and Jean-Louis Schlesser, finished third overall — albeit 19 laps behind the winning Porsche 962C — a creditable result for a debut outing.
At Spa-Francorchamps, Brundle and Thackwell came home fifth, while Schlesser and Hans Heyer retired from their entry due to handling difficulties. Both cars retired at Brands Hatch, and TWR withdrew from the Fuji round due to adverse weather conditions. The season closed at Selangor, where Thackwell and John Nielsen brought the XJR-6 home in second place.
For 1986, the programme expanded to a full season under Silk Cut cigarette sponsorship, and the cars underwent a significant weight reduction programme. The year's highlight came at Silverstone, where Eddie Cheever and Derek Warwick took the outright victory — the XJR-6's sole race win. At Le Mans, all three entered cars retired.
Cheever and Warwick took second and third at the Norisring and shared third place at Fuji. Warwick and Jan Lammers were second at Spa. The season concluded with TWR earning third place in the Teams Championship, while Warwick finished third in the Drivers Championship — solid results that validated the programme's foundations and justified the move to the more developed XJR-8 for 1987.
The XJR-6 served as the essential proving ground for TWR's Group C Jaguar programme. While it never challenged at the very front of the field, it established the engineering architecture, the Silk Cut sponsorship identity, and the driver roster that would underpin the XJR-8 and XJR-9 — cars that went on to win Le Mans in 1988 and 1990. The XJR-6's carbon-fibre monocoque and ground-effect aerodynamic philosophy represented a significant step forward for British sports car racing in the mid-1980s.