Austin-Rover

Rover's intention in Group B was to prove that a naturally-aspirated (non-turbocharged) car could be equally competitive as a turbocharged car. Rover payed Williams Grand Prix Engineering to build the car, since Rover didn't have the same amount of money as Lancia, Audi, etc. to produce a competitive car. The car was mid-engined, and the engine was a 3-litre, 24-valve V6 that put out about 400 horsepower. It had four-wheel-drive, and it had the radiators mounted in the rear as well. It also had large spoilers to aid with downforce; the wings were one of the more successful innovations introduced by the 6R4. The rally program during Group B wasn't very successful, mainly because of a lack of funds.

However, the project certainly wasn't a complete failure. The car's biggest success was definitely its international debut, when the 6R4 captured third place in the 1985 RAC rally, behind the all-conquering Lancias. The engine in the 6R4 later went on to be developed by TWR and was used in the incredible Jaguar XJ220. The 6R4 is popular among rally car collectors, and it is still very successful in rallycross and in the British rally championship.