Retromobile Paris 2023 – Citroën SM Prototype (1973)

The Rétromobile at Versailles is one of the most exciting European events when it comes to the love of classic vehicles. The French nation's great automotive past is beginning to shine once more for a brief period, and brands like DS are using the momentum to carry something from then into the present.

Before the Rétromobile starts on February 1st, we are showing two milestones of French car culture, which will be on display alongside the modern vehicles on the DS Automobiles stand. For DS, the Parisian car brand, Versailles is a home game that shouldn't be disappointed. An exciting Citroën SM prototype was therefore drawn from the well-filled magazines of automotive artefacts.

Citroën SM Prototype (1973)

When I was young, the SM was the most exciting car ever built in France. An SM, it was gold-colored, could be seen again and again in my hometown. In the provinces, an SM, at that time already an old used car, was still good for a spectacle. Because, under the outrageously long bonnet, lurked a Maserati engine.

A prototype from 1973 rolls DS Automobiles in the headlights of Rétromobile. What, 1973, the older readers will now say, and they'll start to do the math. That's right, the SM came onto the market in the summer of 1970 and only 5 years later the dream was over.

What was Citroën planning with the SM prototype?

The vehicle shown served as a test car to examine the driving behavior of the Citroën SM and the hydropneumatics at particularly high speeds. Acceleration, traction and directional stability should be tested and improved. On board the prototype there was an opportunity to modify the chassis parameters even while driving. The load distribution and rigidity of the hydropneumatics could be changed. The SM served as the basis for Citroën racing models, which should not only be based on the SM.

SM prototype with 340 hp and 285 km/h

Anyone who has dealt with the subject of hydropneumatics and Maserati will now swallow hard. The SM was actually an impossible combination of (soft) hydropneumatics and a fairly robust running Maserati V6. In fact, there are even said to be people who classify the Maserati machine as uncultivated and not suitable for the SM.

However, the SM drew some of its magic from the allure of contrasts. The fact that Citroën seriously wanted to be more sporty is demonstrated by the data from the prototype. The 340 liter engine with the three Weber double carburetors delivers an impressive 3 hp, its top speed is 285 km/h. The driving performance must have been breathtaking back then, because the prototype weighs only 1.169 kilograms.

SM prototype at the Rétromobile

In fact, the SM from the series in the highest expansion version achieves a maximum of 180 (and 178) PS. In 1972, that was sufficient for a top speed of more than 220 km/h, making the SM one of the fastest in the country.

The prototype remained in use at Citroën after the end of production of the SM. Pictures from the company archives come from 1977. At that time the SM was presented to a larger audience. The public exhibition at the historic headquarters on the Quai de Javel in Paris was appropriately titled "The Secrets of Citroën". A full 46 years later, the SM is back on the big stage. From February 1st to 5th it can be seen during the Rétromobile.

With images from DS Automobiles