Back in the 1960s Citroen bought Maserati and 50 years ago came up with the fabulous SM. What might have seemed an unlikely partnership was purely strategic. You see Citroen lacked a decent engine, large, powerful and anything with more than four cylinders. They had already started development of a sports version of the DS, known as Project S in 1961. The purchase of Maserati provided the engine. In return Citroen’s hydraulic suspension became a feature of the Maserati Quattroporte, Merak and Bora.

The initial idea was to attempt the Le Mans 24 hour race, but this was soon changed into a premium car to be sold above the DS.

The SM first appeared in 1970 at the Geneva Motor Show in March going on sale in France in September that year. The engine size was a little unusual at 2.7 litres, due to the French taxation system on horsepower. A calculation of swept volume and the number of cylinders and engine speed deciding your taxation class. A somewhat archaic formula based on the RAC one of Great Britain in 1910. The engine was essentially a 90 degree Maserati V8 from the Indy with two cylinders missing. But with double overhead cams per cylinder bank and a very compact 31cm length it was thoroughly modern. It was also very light, the entire unit with its aluminium block weighed just 140kg.

This left the SM with a slightly too small engine and whilst offering decent performance, they weren’t necessarily as fast as expected. In 1973 a 3.0 engine was offered, with a small increase in power, from 168 to 176hp. Bosch D-Jetronic fuel injection already available since 1972.

The SM design is striking, and Citroen did it entirely in house, with Robert Opron who was at the time head of the design department. The silhouette of the SM shows the obvious Kamm tail to the design. It was incredibly aerodynamic for its time; the drag factor was only 0.26. there is some family resemblance to the later CX, which took lessons from the SM and incorporated them in the design.