1973 Citroen SM

In the 1960s, Citroen entered into negotiations with several companies including Maserati, the result of which was the SM sports coupe with a 3.0 liter, 4 valves, V-8 engine developing 180 horsepower. This drove the front wheels via a five-speed synchromesh gearbox. It featured power steering and disc brakes.

Work began on 'Project S' in 1961 to create a sportier version of the popular and high-volume Citroen DS. Many concepts were developed during the nearly decade-long project, and during that time, Citroen purchased Maserati in 1968. Both companies benefitted from this acquisition, with Maserati having access to Citroen's plentiful parts bin, and Citroen gaining access to Maserati's high-performance engine technology, experience, and expertise.

In March of 1970, Citroen introduced the 'SM' at the Geneva Motor Show, with sales commencing in France later that year, in September. All examples that left the factory had left-hand-drive configuration, however, right-hand-drive convertibles were available from aftermarket companies.

The origin of the name remains a mystery, with several theories including the 'S' may be in reference to the Project 'S' designation. Since it was a sportier version of the Citroen DS, the 'M' perhaps refers to Maserati. It is often assumed the SM represents 'Systeme Maserati' - translated to 'Sports Maserati' - or 'Serie Maserati.' Other theories suggest the name represents 'Sa Majesté' (Her Majesty in French), which would complement the DS model's nickname of 'La déesse' (The Goddess).

The completely new engine was designed by Giulio Alfieri and given an unusual 90-degree angle between cylinder banks allowing it to be assembled on existing V8 tooling. The engine was compact and lightweight, and later versions would be used by Maserati to power its junior mid-engine supercar, the Merak. The 2.7-liter size was selected to limit the tax owners would have to pay to satisfy the French puissance fiscale taxation. With three Weber 42DCNF carburetors, the 309-pound engine, mounted behind the front axle, delivered nearly 170 horsepower.

Many innovations pioneered on the DS were incorporated into the SM, including the self-leveling lights that swiveled with the steering and the hydro-pneumatic (oleo-pneumatic) self-leveling suspension. The self-leveling lights were illegal in the United States and vehicles exported there were devoid of this feature.

One of the controversial but advanced features of the SM was its variable-assist power steering. Since it was a rather powerful front-wheel-drive vehicle, steering (at the time) was unpredictable at high speed. To increase safety, a new proprietary steering system was developed by Citroen called DIRAVI, which adjusted hydraulic pressure on the steering centering cam based on vehicle speed, resulting in predictable steering at any speed. It required little effort from the driver to turn at low speeds and more effort at a higher speed. When the steering wheel was released, the steering would return to center - a straight-ahead position.

The braking system used on the DS was modified for use on the SM. While the DS used rear drum brakes, the SM had disc brakes at all four corners, with the front brakes being inboard, and were cooled by large ducts located on the underside of the car, near the front. The hydraulic braking pressure is self-adjusted from front to rear depending on the weight distribution of the vehicle.

At the time, Citroen was the world leader in passenger car aerodynamics, and the SM continued this trend with a class-leading drag coefficient that allowed it to reach 140 mph, making it the fastest front-wheel-drive car ever at that time. The styling was by Citroen's chief designer Robert Opron, who penned similar lines to the Citroen CX and Citroen GS. The CX's rear fender skirts were applied to the SM, a Kamm tail was in the back, and it had a wide front frack and a narrower rear track.

The interior featured oval gauges and highly adjustable bucket seats with center padding formed from many individual 'rolls.'

Fuel injection replaced the carburetors in 1972, an automatic transmission option became available in 1973 and the engine was enlarged to 2,965 cc. Production continued until 1975 following Citröen's acquisition by Peugeot.

In 1971, the SM placed third in the European Car of the Year contest and won the Motor Trend Car of the Year award in the United States in 1972.

During its production lifespan, a total of 12,920 examples were built. 868 examples were sold in its inaugural year, followed by 4,988 in 1971 - its best year. From there, sales dipped to 4,036 in 1972 before falling even further to 2,619 in 1973. Just 294 were sold in 1974 and 115 in its final year. Approximately 2,400 examples were sold to the North American market in 1972 and 1973.

by Daniel Vaughan | Oct 2006