The Ferguson 4WD system known as the Ferguson Formula was developed by Harry Ferguson Research Ltd that was formed by Harry Ferguson, an Irish engineer.
Ferguson originally developed tractors with David Brown as the Ferguson-Brown company. The uniqueness was the hitch at the back to connect multiple types of equipment. David Brown went on to be the owner of Aston Martin when they won Le Mans at the end of the 50s and is the reason why Astons use the DB moniker.
Ferguson had a deal with Henry Ford to use the hitch on Fordson tractors but they fell out in the late 40s and that started a protracted legal battle. Ferguson started to make his own tractors again and 1953 merged with Massey-Harris to form the Massey Ferguson company.
In the early 50s, Ferguson sold his stake in the tractor business and founded Ferguson Research to initially build a 4WD car. The initial prototypes were dubbed the “R” series. The R4 from the late 50s included one of the first semi-automatic gearboxes and anti-lock brakes developed in conjunction with Dunlop.
To prove a point, the company decided to build a Formula 1 car. This car, the Ferguson P99 was the first 4WD F1 car and used a 1.5 litre Coventry Climax engine. It had a 50/50 weight distribution and 50/50 torque split front and rear. Ferguson died soon after the car entered its first race and the company continued the development and it ran in several races in Europe and Australia.
Ferguson used this experience to produce the Ferguson Formula – the 4WD system for Jensen Motors – not to be confused with the haemorrhoid treatment or the IQ test! Richard & Alan Jensen had been very interested in the R5 prototype in the late 50s and by 1964 had signed an agreement to jointly develop a car with the transmission – the first prototype was the CV8-FF. Jensen then launched a completely new car, the Jensen Interceptor and the Jensen FF.
The FF was the 4WD version of the Interceptor and built for 5 years (1966 – 71) and only 320 were built. It was the first production car with permanent 4WD and it differed from the P99 by using unequal torque split with nearly 70% to the rear, now common on today’s all wheel drives. The car was fitted with a 3 speed Torqueflite auto box with a torque converter and a 6.2 litre Chrysler V8 good for 140mph.
The transmission deployed a slave shaft that used interconnecting gears from the main rear prop shaft. The front prop shaft was driven by either duplex or triplex chains (based on the build date) from the slave shaft. It deployed three differentials, a centre one and then front and rear diffs to transfer power to the wheels. The transmission also used a two way centre clutch that has been described as two motorcycle clutches bonded together. These clutches worked very well to provide the torque through to the wheels that required it, although sometimes when the car was under stress the ABS would kick in assuming that traction had been lost when it hadn’t. In the late 60s, the Jensen was described as the world’s safest car!
Towards the end of the 60s, many F1 teams wanted to use the Ferguson design and BRM, Lotus & Matra were given access to the transmission system for racing purposes.
Tony Rolt, the 1953 Le Mans winner for Jaguar who had helped set up Ferguson Research, created FF Developments in 1971 to help a number of manufacturers fit the system to their cars which included the Jaguar XJ220, Ford RS Cosworth models and the McLaren F1 sports cars. This company is now called FFD-Ricardo after being acquired in 1994 by the Ricardo Group and still provides technology and development for the world’s high performance vehicles.