The MG Metro 6R4 was a Group B race car with four-wheel drive and a mid-engine configuration. It bore a slight resemblance to the road-going MG Metro city car, basically only sharing its name. The development of the car was the work of Williams Grand Prix Engineering and Formula 1 designer Patrick Head. The compact Metro shape had a mid-mounted engine and four-wheel drive transmission enclosed within a semi-monocoque seam-welded tubular chassis. The David Wood-designed 3-liter V6 engine used some of the same architecture found in the Cosworth DFV. It had twin overhead camshafts, and four valves per cylinder. Most of the competition in Group 4 did not have a turbocharger - the MG Metro 6R4 did.

There were two versions of the 6R4, the Clubman model which produced roughly 250 horsepower, of which around 200 examples were built. A further 20 examples were built to International Specifications and powered by a 410 horsepower engine. In competition trim, the MG 6R4 had a redline of 10,000 RPM, and could race from zero-to-sixty mph in 2.8 seconds.

The MG Metro 6R4 was the brainchild of Austin Rover Motor Sport Chief, John Davenport, who wanted to follow the lead of Audi's permanent 4WD transmission. He collaborated with Patrick Head and John Piper from Williams F1. In December of 1982, the finished prototype was delivered to Cowley for in-house development to begin. By 1984, the 6R4 was ready for the press.

In 1986, Group B rallying was scrapped after several fatalities among drivers and spectators. This denied the 6R4 of any international success, as by this point in history, most of its teething problems had been resolved.

The MG Metro 6R4 participated in the Lombard RAC rally in November of 1985, where works driver Tony Pond finished in third place. During the 1986 season, the 6R4 raced at Monte Carlo, Sweden, Portugal, and Corsica however none of the Metros managed to complete a course. Most of the problems were related to the V6 engine.

At the end of the season, Austin Rover withdrew from the rallying scene. In 1987 all the engines and left-over parts were sold to Tom Walkinshaw Racing, with the V6 engine later appearing in the Jaguar XK220.

by Dan Vaughan