1971 Citroen SM road test

2015 / 2016 Drive-My

Citroen’s super machine. For years Citroen made slow, ugly, interesting cars. Now they’ve made a fast, beautiful, fascinating car – road test by John Lamm. I feel this tremendous compulsion to tell you uncategorically that the Citroen SM is the best ear in the world. But that would immediately send you right down on my back to explain why, and no one has ever told me just what makes any car the Best Car In The World. The SM is neither the fastest, nor the cheapest, nor the most expensive, nor the most beautiful, nor the least attainable, nor the most status rendering automobile in the world. Yet it has to be (he most advanced car from the safety-engineering standpoint and if one is to be properly analytical about it, that should make it the best in the world. It certainly is one of the most fascinating to drive.

1971 Citroen SM road test

It had just begun to rain when I picked up the SM from Citroen in Paris. I was given a short orientation drive, as will everyone who buys one. It is such a different feeling car that you should get a short course before striking out on your own. Right off, the most fascinating feature about the car is the steering. In town, it’s a dream, because of the very fast 9.4:1 overall ratio in the power rack-and-pinion unit and it only takes one complete turn of the steering wheel to take the front wheels from a full right lock to a full left lock. It needs only 34.5 ft. to turn a full circle. As a comparison, the quick Porsche 914 has a ratio of 17.7:1, needs 2.5 turns lock to-lock and has a turning diameter of 36.1 ft. So you slip easily through traffic, being careful that the quick ratio doesn’t fool you into clipping a curb. This light, quick system would be dangerous on the freeway where a muscle spasm could mean a lane change, so they’ve added a centrifugal steering regulator that runs off the back of the transmission and as the speed increases, so does steering effort. Bobweights inside the regulator bring pressure on a slide valve that regulates pressure in the power steering unit, so as you accelerate on the freeway, you can move the wheel from side-to-side and feel the tension increase with speed. As if that weren’t enough, the steering has a self-centering system that returns the wheels to the straight ahead whenever you let go of the wheel, even at a standstill.

Next on the interest scale, is the Maserati engine that powers the SM. It’s a dual-overhead-cam V6 of 163 cubic inches and puts out 180 SAE horsepower at 6250 rpm. It has a light alloy block and head, a 4-main bearing crank and carburetion is three 42DCNF Webers. The engine has an oversquare 87mm bore and 75mm stroke, though short stroke engines are supposedly thought of as dirty smog engines. But the figures don’t pass on the surprise in finding the engine not the finicky beast you expect dohc, Weber-carbureted engines to be. It was smooth and never gave a bit of trouble in response or starting. In fact, it felt in no more need of some mysterious accelerator-clutch reflex action than a common U.S. V8, and less than the Boss 302 or Chevy Z/28-type engine. The car has front-wheel drive, like all Citroens, the company figuring that layout offers the most in terms of safety and person packaging. Brakes are four-wheel discs, operated by a rubber bulb between the clutch and accelerator. I thought that was novel, but didn’t appreciate, until we got the car on a test track in the U.S., the novelty of the entire system. The all-synchro 5-speed Citroen transmission was smooth and not the jumble one always fears a 5-speed will be.

Suspension is four-wheel independent, with anti-roll bars front and back. There is, of course, the famous Citroen hydropneumatic suspension that will automatically maintain an even ground clearance. You can. as with all such Citroens. pick the height you care to be from the ground with the system.

Of course, one reason why all French cars ride well is their excellent seats and the SM is no piker. The seats are infinitely variable for fore-aft movement and scatback rake; combined with a steering wheel that allows both up/down and in/out movements with one control lever, the car could easily fit about 98 percent of the people in the world over the age of 18. There is a speedometer and tach and a huge cluster of idiot lights surrounding a red master disaster “STOP” light on the dash. Gauges for water and oil temperature and fuel level sit just above the ventilation air conditioning outlet and controls. The back seat is a bit cramped, but no worse than, say, a big Chevrolet, and the seats dip down enough to the rear to at least make you feel like you have more room than you do. Finish is excellent and the sealing stood up perfectly to several downpours.

Way up on the interest list, but a sure victim of the U.S. safety standards, is the headlamp system. Along with the center-mounted license plate, the Cibie lights reside under glass just above the bumper and have three lamps on each side — a dipped lamp, a wide main beam and a long-range lamp. All are quartz iodine. In addition to just being a very superior system, the long- range lamps swivel just slightly ahead of the steering, lighting wherever you are going and the whole unit is mounted on a device that keeps them level with the road despite added loads or what have you. The effect at night on a winding road is awe inspiring, almost like bringing the daylight with you. The man (or men) who devised the laws that keep that system out of the U.S. have done us all an injustice.

Styling is, of course, a matter of personal taste, though you somehow get the feeling that Citroen really did design the car this way because it is more efficient and they don’t seem to care; as they state, “the shape of the SM makes 110 concession to fashion.” How true, but it does pack that Maserati engine and front-wheel – drive system up front, four adults surprisingly comfortably in the middle and a full 20.67 cubic feet of luggage space in back — most large American sedans have about 12-15 cubic feet. To give you a size comparison, the SM’s wheelbase is 116.17 inches, while a Torino Cobra runs 117 inches. Overall length is: SM. 192.64 inches; Torino. 206.2 inches and weights are SM. 3.370 11, Torino, 3,586.

That was the car in France, where it is like a small god to the average Citroen 2CV driver. But what happens to the SM in the U.S., where drivers are used to high-powered cars, where the roads are too smooth to use that Citroen suspension to its full advantage and the speed limits too low to make use of the Maserati engine? You just start appreciating the car for different reasons. It quickly becomes perhaps the world’s greatest freeway car. ready to deal with long normally-boring sections and traffic jams. It’s the car least inclined to make you bored with driving to work. In the midwest they’ll love it for its traction in rain and winter and for the way it will smooth out roads that have been deeply scarred by the thawing and freezing of early spring.

We got ours shortly after the Los Angeles Auto Expo, where it had been shown as a European model. For our testing, though, it magically became an Americanized version — externally at least. First hint and the most disappointing, was the way they had to muck up the front end by removing the glass from the headlamps and then replacing them with round all-American headlamps. It’s still an interesting, relatively good-looking front end, but a zero compared to the European edition. The engine was still a European version, though it had passed U.S. tests.

Our first test of the car was with people. The results were very favorable. We parked the car behind the main Petersen Building and the phone calls started, everything from “What is it?” to “Can I drive it?” Every place we glided with the car, people rubbernecked and stretched to see it. The two leading comments were, “What kind of car did you say it was?” and “But Citroen used to make such ugly cars.” Only one person ever told me she didn’t like the looks: about twenty persons, many driving Mercedes and Lincolns, wanted to know where they could buy one. Interestingly, though, the most stares came from Porsche drivers.

Our second test was mechanical, to answer that other very popular question, “What’ll she do?” Briefly, she’ll do very well, thank you. Since this is no ordinary car, we could do no ordinary test, instead dusting off all the test equipment Sports Car Graphic’s former tech editor Paul Van Valkcnburgh had devised to really delve into a car’s performance. First there’s aerodynamic drag, which can roughly be equated to “streamlining” or how much air a car disturbs while running down the road (in this case at the mean speed of 100 mph). That disturbed air has a drag effect, like the car towing so many extra pounds of weight. In the SM’s case, there are 231 pounds of drag at 100 mph. As a comparison with cars of similar cost and interior space, the Jensen Interceptor II has a drag of 385 pounds, while the slightly larger Mercedes 280SE Coupe W111 has a drag of 450 pounds. This drag factor relates directly to better gas mileage and greater top speed for less horsepower.

Next item on the read-out sheet is acceleration. The favorite benchmark is, of course, 0-60 which the SM manages in 8.6 secs. As a comparison, that puts it into a class (roughly) with the Datsun 240Z (9.1 secs.), and the Mazda RX-2 Wankel (9.1 secs.). Quarter-mile times ran from 16.76 secs. (84.66 mph) to 17.14 (82.79). The interesting point about the Maserati V6, though, is the amount of low-end power that is available, especially in consideration of the engine’s overhead cams, Weber carburetors and other pieces that usually mean a more peaky engine with plenty of power way up the rpm scale, but with limited power at low rpm.

Along with above-average seats and suspensions, French cars have always been a bit ahead of the game with brakes, the SM carrying the whole process still another step ahead. Basically there are the four discs, a equalizing/modulating device and accumulator. Under normal circumstances, if you hopped on the brake bulb in a panic situation the nose dips and the modulator will hold the brakes right to wheel skid (1g in this case), then ease up momentarily. Like an anti-skid system it will grip, ease up, grip, ease up, bringing you to repeated non-lockup stops. As a safety measure, there’s an accumulator that stores up enough pressure for 40 panic stops with a dead engine. Even that fail-safe device has a back up, the handbrake, which will supply one last ditch chance to stop.

Finally to the skid pad. There was one serious limit to the car’s pad performance, the tires. With the car’s inherent front-wheel-drive tendency to strong understeer in the 200-foot circle, the tires began to smoke, then chunk. Even with that limit, the SM managed to generate 0.704g to the right, 0.712 to the left. On the road course, the SM showed only a trace of its fwd heritage, with above-average handling, but even that wasn’t its real forte. Take it to a rough road, with dips, ruts and railroad crossings and when the rest of the cars have had their ends skid and chatter right off the road, the SM will be quietly motoring away.

Now don’t think you can get all this for nothing. In fact, the SM will sell for around $10,500 in the U.S. Compare it then to a $10,000 Cadillac Eldorado or Lincoln Mark IV and they look like pikers. To ease the pain, there will be a Borg Warner automatic coming in shortly after production starts and a 4-door will be close behind. The future looks good for the SM. That front end seems a natural to accept a safety bumper and somehow you know that Citroen will make that Maserati engine conform to smog laws, right up to fateful 1976 — maybe even later. In Paris I had asked Monsieur Jean-Paul Cardinal of Citroen if they could do it, perhaps having to redesign that chassis platform to make room for catalytic reactors and afterburners. He said that if a redesign was necessary, they would do it, but perhaps they might have a new answer to the problem and could use the existing chassis. You could scoff at a lot of manufacturers if they said that, but don’t ever scoff at Citroen. They build the SM.

Above: SM’s heart, a docile Maserati V6 with low end torque. Right: Only possible styling fault is slightly garish taillamp. Below: Fascinating interior has full instrumentation; good visibility; soft, fully adjustable, comfortable seats.

Top: European SM front is beautiful, with six Cibie lamps, turning road lights under glass. Uncovered U.S. version is monument to our asinine lighting laws. Above: SM has constant 6.1-inch normal ground clearance but you can manually change that to one of five possible heights. Extreme up and down are for jacking.

Hidden in that plethora of pieces, is the SM’s Maserati V6. Mounted behind the front-wheel drive axle, the engine is actually facing the rear. Three Weber 2-bbl carbs feed the dohc, 163-cu.-in. power plant. Other front-mounted plumbing (compressor, alternator and suspension pieces) would be vulnerable in accident.

Car Citroen SM 2.7
Wheelbase 116in
Overall width 72in
Front track 60in
Ground clearance (unladen) 6in
Front headroom (seat uncompressed) 37iin
Rear headroom (seat uncompressed) 35in
Front legroom (seat forward/back) 37/43in
Overall length 192in
Overall height (unladen) 52in
Rear track 52in
Front shoulder room 57in
Rear shoulder room 55in
Rear legroom (seat forward/back) 23/28in
Mechanical Specification
Weight (in lbs kerb) 
Steering rack & pinion
Turning circle
34ft 6in 
Turns (lock to lock)
Brakes discs front – Diameter (in) 11.8, disccs rear –Diameter (in) 10.0, with servo, 
Material (cylinder head) lig htalloy (block) light alloy
Main bearings (number) 
Cooling system
Valve gear layout
four overhead camshafts
three Weber 42 DCNF / Bosch fuel injection
Compression ratio
Capacity (cc)
Bore (mm)
Stroke (mm) 
Power (net bhp/rpm)
170bhp at 5500
Torque (net lb ft/rpm) 
170lb/ft at 4000rpm
five speed all synchromesh
Top gear mph per 1000rpm 22.5 mph
Ratios: 1 st 2.93 2nd 1.94 3rd 1.32 4th 0.97 5th 0.81
Final drive ratio 
Clutch : Make: 
single dry plate
spring single plate  
Wheels and Tyres     
Wheels (type and size) steel 15in x 6in rims
Tyres (type and size) Michelin 195/70 VR-15X
Replenishment & Lubrication     
Type of oil 20W/50 
Engine sump capacity (pints) 12.25
Engine oil change interval (miles) 3000
Gearbox and final drive capacity (pints) 3.9
SAE 80
Gearbox capacity (pints)
Final drive capacity (pints)
Number of lights Six + 2
Tungsten halogen
Battery (make) Fulman
12 volt 300/70 a.h.

Safety belts Yes, Tool kit Yes, Heater Yes, Rear window heater Yes, Jack Yes, Radio Extra Windscreen washers Yes, Cigar lighter Yes, Map light Yes Fog lights Extra Spot lights Extra Clock Yes Fresh air ventilation Yes Hazard warning Yes Sun visors Yes Tachometer Yes Sliding roof No Vanity mirror Yes Reversing lights Yes Coat hooks IMo Grab handles Yes Reclining seats Yes Wipe — wash facility Yes Map pocket Yes Bootlight Yes Engine compartment light Yes Adjustable steering wheel Yes Oil pressure gauge No Oil temperature gauge Yes Water temperature gauge Yes Ammeter No Electric window winding Yes Petrol filler lock Yes Fuel low level warning Yes Underseal Yes Glove locker Yes Parcels shelf (front) No Parcels shelf (rear) Yes Headrests Yes Steering lock Yes Parking lights Yes Door armrests Yes Rear armrest No Front armrest No.

Front Independent with double wishbones and self-levelling, interconnected hydropneumatic units
Rear Independent with trailing arms and self-levelling, interconnected hydropneumatic units
Price structure (1971)
Basic price, £ 3750
Purchase tax 939
Extras (including tax)
Leather trim 186
Tinted glass 48
Airconditioning 206
Radio 112
Fog lamps – 2 18
Automatic transmission 300
Power steering basic equipment
Airconditioning (including tinted glass)
Indicates fitted to test car
Price as tested £5130
Length and conditions of guarantee Six months, labour and materials. Exceptions to guarantee Lubricants, anti-freeze, tyres, glass. Number of free services One at 600 miles.

Cost of schedule servicing for 12.000 miles or one year exclusive of oil. hydraulic fluid, filters, etc. Not yet available. Cost of oil change at £1.20 per gallon £1.30.

Braking (Actual stopping distance in feet)  
30mph  47
70mph  156
Fuel consumption  
Overall (mpg)
Driven carefully (mpg) 27.1
Star rating 5
400/440 miles
Tank capacity
20 gallons
From standstill to mph. in seconds
0-30 3.3
0-40 4.8
0-50 6.4
0-60 8.2
0-70 11.4
0-80 14.3
0-90 18
0-100 23
0-110 30

Speeds in gearsFrom minimum to maximum in each gear.


2 60
3 90
4 115
5 135



Thanks to Citroen SM Drive-My Club

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