1974 Citroen SM

Citroen acquired Maserati in 1968, giving them access to a high-performance engine for its 'Project S,' in many ways the last of the DS concept. Unveiled at the 1970 Geneva Salon, the new Citroen was considered the ultimate 'gentleman's GT.' With the powerful and smooth Maserati Quad OHC V6 engine, it was the fastest front-wheel drive in the world for the following ten years. The elegant and sculpted shape was penned by Robert Opron and boasted an incredible aerodynamic efficiency (initially published as having a drag coefficient of 0.26 but later revised to 0.339) that surpassed most road-going vehicles of the era. Its teardrop styling included a Kamm tail and fender skirts at the rear, ventilation intakes on the hood, and a wide front track tapering to a narrow rear track.

The Citroen SM went on sale in France in September of its introductory year in left-hand drive only, although right-hand drive conversions were later offered in the UK and Australia. It was Citroen's flagship vehicle that would demonstrate just how much power and performance could be accommodated in a front-wheel drive design. During its production lifespan, lasting from 1970 to 1975, a total of 12,920 examples were built with approximately 2,400 sent to the United States. In 1972, it won Motor Trend's Car of the Year award in the United States.

Project S began as a sports variant of the Citroen DS, a front-wheel drive executive car manufactured from 1955 to 1975. Named the 'SM,' this may have been the combination of the 'Project S' designation for 'S' and the 'M' for 'Maserati.' Thus, it is assumed that 'SM' represents 'Serie Maserati,' 'Systeme Maserati' or 'Sports Maserati.'

Mechanical Specification

Engine
The Maserati high-performance, four-cam, 90-degree V6 engine displaced 2,670cc and delivered 170 horsepower at 6,250 RPM with three Weber carburetors. By 1973, output had risen to 180 horsepower when displacement increased to 2,965cc. The lightweight, all-aluminum engine, positioned behind the front axle, was designed by Giulio Alfieri and had an unusual 90-degree angle between cylinder banks, giving it the flexibility of being assembled on existing V8 tooling. Bosch D-Jetronic electronic fuel injection, first offered in 1972, delivered 168 hp. A singular example was fitted with a Maserati V8 engine with 260 hp and another example had a turbocharged version of the V6 engine for setting land speed records at the Bonneville Salt Flats.

Transmission
Most of the Citroen SM vehicles receive a five-speed manual transmission, with a few fitted with a three-speed Borg-Warner automatic transmission that was optional in North America in 1972 and 1973, and in Europe from 1974 to 1975.

Chassis
The Citroen SM rested on a 114.2-inch wheelbase platform with an overall length of 192.6 inches, a width of 72.3 inches, and stood 52.1 inches tall. Like the DS, it had a hydro-pneumatic suspension with front parallel control arms, rear trailing arms, and front and rear anti-roll bars. Disc brakes with hydraulic assist at all four corners provided the stopping power. The front brakes were inboard and cooled via large ducts on the front underside of the car. The hydraulic system adjusted pressure front to rear according to the weight in the rear of the car.

There were self-leveling lights that swiveled with the steering, but since this technology was not legal in the United States, U.S.-destined cars were devoid of this technology.

A variable assist power steering combated torque steer common to high-performance, front-wheel drive vehicles, and adjusted hydraulic pressure on the steering centering cam according to vehicle speed, allowing a consistent steering feel at any speed. The steering was responsive, could turn easily at low speeds, and had two turns lock-to-lock. If the driver let go of the steering wheel, the steering would return back to center, to a straight-ahead position. Additionally, the height and reach of the steering column could be adjusted.

When the wipers were on the 'low speed' setting, the system monitored the current needed to drive the wiper motor. When it rained, the current's need was higher, and the system would adjust accordingly.

The standard wheels were steel with stainless trims. A factory-fitted option was the Michelin-developed lightweight caron-reinforced resin wheels intended for off-road racing, and weighed less than half the standard weight.

The hood (bonnet) was comprised of aircraft-grade aluminum, and the brightwork was made from stainless steel. Chrome was used for the 'plastichrome' 'SM' trim at the rear base of the rain gutter.

Interior
The Citroen SM had a small oval steering wheel, oval gauges, and adjustable bucket seats with center padding composed of many individual 'rolls.' When equipped with a manual transmission, the shift lever 'boot' had a highly stylized chrome gate.

Performance
The factory-quoted top speed of the Citroen SM in 1970 was 137 mph (220 km/h), with independent testing later revealing speeds of as much as 146 mph (235 km/h). The special V6 Citroen SM with a turbocharger developed by Jerry Hathaway (SM World) achieved a top speed of 202 mph (325 km/h) at the Bonneville Salt Flats in 1987, setting a land speed record for production vehicles in its class.

Production
Most of the Citroen SM vehicles were built in 1971 and 1972, with 4,988 in the former and 4,036 in the latter. The final two years saw the lowest levels of production, with 294 examples built in 1974 and 115 in 1975. 868 examples were built in 1970 and 2,619 examples in 1973. 1,250 examples were sent to the North American market in 1972 and 1,150 in 1973.

by Daniel Vaughan | May 2023