Citroën SM

The Citroen SM has changed little during the three years it's been in production. The most significant modification being the replacement of the original twin-choke Weber carburetters with Bosch electronic fuel injection. As our original test was on an early example and over a lowish mileage, this change in carburation provides a good excuse for us to reappraise the car.
The SM was the first produce of the Citroen/Maserati marriage, and it still tops the French company’s range. To recap, it has a V6 Maserati engine driving the front wheels through an excellent Citroen-designed five-speed gearbox. The suspension is basically the soft-riding self-levelling road – hugging  hydropneumatic system used for the DS, with the addition of anti-dive and stiffer roll bars. The brakes are power operated discs with automatic compensation for weight -transfer, and the steering is a fully –powered high-geared rack and pinion system with artificial feel that varies with speed and lock. All very complicated, but does it work?
The SM has a top speed comparable to that of the Jensen Interceptor yet an engine of less than half the capacity, partly because of relatively low drag, partly because Maserati have squeezed a very healthy output from their lovely all-alloy four-cam V6.
However, progress by other manufacturers has forced us to temper our original wild enthusiasm for some aspects of the car’s design. For instance, we find the brakes too sensitive, and the unique super-responsive power steering takes a lot of getting used to. The car is also rather noisy: pleasing though the sound of the engine may be, it is tiresome at anything near full throttle. Road noise is also disappointingly high. By way of a contradiction it is at high cruising speed that the car really comes into its own. Ideal gearing and very low wind noise make light work of continuous 120 mph cruising. So much so in fact, that one has to keep a wary eye on the speedometer. The five-speed gearbox is also a joy to use.
We thoroughly enjoyed our reacquaintance with this unusual motorcar; anyone who can conquer its idiosyncracies (sic) will find it an appealing machine. Others who can't may find the concentration required to drive it well on our crowded roads inappropriate to a price tag of over £6000. It’s (sic) size doesn’t help, either: the SM is an exceptionally large car by European standards - just over 16 ft long and 6 ft wide‚and it bulges out of the driver's sight in all directions. Yet its accommodation is poor as there is little rear-seat legroom and the boot is of quite modest size.

PERFORMANCE ****
A couple of churns were always sufficient to start the engine, even after a night out in the frost. Cold start enrichment is automatic and the engine pulls strongly straightaway.
The lovely-looking Maserati power plant (not that you can see much of it) is sited well back under the rearmost part of the enormous sloping bonnet. It is an all-alloy 90 deg V6 with four chain-driven overhead camshafts. French fiscal laws demand high taxes for vehicles over 2800 cc, so the capacity has been restricted to 2670 cc. Even so, the output is excellent; with the new Bosch fuel injection system it produces 178 bhp at 5500 rpm, 8 bhp more than before. Maximum torque of 171 lb ft is developed rather high in the range at 4000 rpm but, as our top gear acceleration figures suggest, the curve is a flat one and the engine will pull strongly from at little as 2000 rpm.
As with all big Citroens, our standing start accelerations were rather traumatic. Too many revs and you provoke vicious and damaging tramp, too few and you fail to induce wheelspin and thus lose time. We achieved our best 0-60 mph times with rather fierce initial clutch slip followed by a little wheelspin: even then we were a little outside Citroen’s claim of 8.0 sec. The injected car is 1.3 secs faster to 60 than the carburetter version though, and 2.9 secs quicker to 100 mph.
Acceleration times in fourth and third gear are unaffected by the change in induction; top gear times, however, have increased due to a substantial rise in the internal gearing. Citroen claim a top speed of nearly 142 mph: unfortunately we were unable to check this accurately though we feel it is slightly optimistic, considering the small power increase and the 135.2 mph attained with the earlier cars.
In the main the engine is very smooth, though there is a slight harshness between 4500 and 5000 rpm. Also on occasions the engine staggers and stutters momentarily as though the injection system has been caught out and the fuel isn't getting through.

ECONOMY ***
Our test car was inordinately thirsty, giving an overall consumption of just 14.8 mpg on 4-star petrol. At best it rose to almost l9 mpg and at worst it fell below 13 mpg. This compares poorly with the carburetted model which managed 17.2 mpg. We have no way of measuring the steady speed consumption of the Bosch electronic injection at present so we cannot compute a touring consumption. The range, however, would be around 360 miles from the 20-gallon tank.
Oil consumption for the 1300-mile test was negligible.

TRANSMISSION *****
Mounted ahead of the Maserati engine is a Citroen-manufactured five-speed gearbox. And very good it is too. The longish lever rocks through a wide gate with the first four gears in the conventional H pattern and fifth up to the right. Reverse occupies the sixth slot and is selected by first lifting the lever upwards.
Fourth gear synchromesh on our test car was weak and resented fast changes, but the other gears could be selected as fast as your hand could move with surprisingly little baulking, making the gearohange a very satisfying one. A spring bias ensures an easy second to third action, though fourth to fifth requires a more careful movement.
Originally the five ratios were closely stacked, providing a continuous surge of acceleration through the range. Now, though the lower four remain unaltered, top has been raised significantly in the interests of relaxed and unstrained cruising.
The clutch engages very smoothly, but is a mite heavy and long in travel for continuous town driving. It also, slipped rather too readily on the 1 in 3 start.
One unfortunate trait of the transmission is the snatch that sometimes occurs at low speed, making it difficult to exploit the engine's excellent low speed tractability.

HANDLING ****
Initially the steering feels very strange indeed and most drivers didn't like it at first. At low speed it seems impossibly direct with just two turns from lock to lock; it also has a strong self-centring action, even at a standstill. As the speed rises, the amount of artificial feel, or resistance at the wheel rim increases and the directness becomes less noticeable. Transferring from a low-geared car with heavy unassisted steering can be really alarming, as the tendency is to apply too much lock too quickly, making the car swerve and snake.
Only when fully accustomed to this exceptional response (and most drivers would probably need several hundred miles to acclimatise), can you really appreciate the car’s exceptional handling.  You aim rather than steer, as little knowledge of the increasing understeer is transmitted via the small steering wheel and the limit of dry road adhesion is high. Even with deliberate provocation we never succeeded in making the tail break away. In the wet you have to be careful not to apply too much power out of the corners, when the inside wheel will spin and tend to make the car snake. The understeer also builds up much more rapidly on wet surfaces of course, but the tendency is for the driver to lift off long before he comes to any harm.

BRAKES ***
You need powerful brakes to stop 1 1/2 tons of motor car. The SM has them. There are separate circuits for the front and rear discs which are power operated by a small rubber-covered button in place of the conventional pedal.
A mere 40 lb pressure is all you need to give a 0.97g stop from 30 mph. Just 25 lb is sufficient for 0.60g. In consequence very controlled footwork is needed, especially in the wet when it is all too easy to lock the wheels. This lightness makes the brakes too sensitive in town and you have to be very careful and gentle to avoid jerking. At higher speeds, the brakes feel much better and the anti-dive geometry of the suspension does make the car a little more comfortable to drive than the ordinary DS, though there's still a lot of attitude change according to whether the car is braking or accelerating.
Our 20-stop fade test caused an initial rise in pressure of as much as 50 per cent, to the accompaniment of a very strong smell of cooked linings and juddering from the front. However, after the ninth stop the brakes virtually recovered though the smell re-occurred later on. The water splash had no effect whatsoever.
Sadly, the SM's handbrake failed to meet even the minimum legal retardation from 30 mph (as did that of the last car), managing a meagre 0.l8g. Admittedly it is unlikely to be required in an emergency thanks to the divided circuits, but it wouldn’t even hold the car on a 1 in 6 slope, let alone the l in 3 that many cars manage.

ACCOMMODATION **
There is ample legroom in the front when using the car as a two seater: for four occupants there has to be a certain amount of sharing. Even with the front seats well forward, there is little leg or head room behind. The rear backrest is also too upright for comfort on long journeys. A central armrest can be folded down to provide the necessary lateral support.
Access to the rear is good. A lever on the side of the front seats releases the tilting and the catch on the seat runners, allowing the whole seat to slide forward. To return to the same setting you just push the seat back, whereupon it locks automatically.
Oddments can be stowed within the four armrests, which have neat pop-up lids; in the tray on the console; and on the large parcel shelf at the rear. The spare wheel steals a lot of boot space but we managed to pack in 9.0 cu ft of our test luggage.

RIDE COMFORT *****
The SM's ride is noticeably firmer than that of the DS though we didn't feel any less comfortable because of it. It doesn't wallow or crash on to the bump stops on hump-back bridges as does its sister car, though there is a certain harshness at low speeds when crevices jar the body far more than they would an XJ6. Brisk crosscountry (sic) travel, when you're constantly transferring from throttle to brake, emphasises the pronounced change in pitch attitude to which the car is prone. Some people found it quite disconcerting. Travelling fast on main roads, however, the car develops that uncanny magic carpet ride that is unique to these hydropneumatic Citroens; we know of no better riding car in such circumstances.

AT THE WHEEL *****
The seats are narrow and unusual in that the backrest tilts from the lumbar region rather than from the base of the spine. Fore and aft adjustment is sufficient rather than generous and the cushion has three alternative tilt positions at either end. Though very comfortable, the seats lack lateral support. The steering column is adjustable too, and with the clamp released both rake and reach can be set to taste.
At first the pedals feel odd and awkward, as they are all quite different. The clutch is of the pendant type, the brake is a small button on the floor and the throttle a big organ pedal set well above the brake. Surprisingly you can heel-and-toe with practice, even though the throttle requires as much, maybe more, pressure than the brake.
The minor controls are excellent. The foremost of the two left-hand stalks operates the (non-return) indicators, the horn and headlamp flasher. The one behind controls the two-speed wipers and "electric washers. On the right a single stalk looks after the complicated lighting system.
The only control that is badly placed is the handbrake, which is set too far back‚ particularly in our test car as it didn't have any effect until the lever was in the upright position and at the limit of its travel. The static Toric belts are easy to put on (though difficult to adjust for length) but they have to be kept tight otherwise they slide off your shoulder. What a pity the car doesn't have Toric's marvellous inertia reel belts.

VISIBILITY **
Visibility is not one of the car's strong points. Initially, most people will choose a high seating position to help them aim this six-feet wide giant, otherwise you can't' see the far side of the bonnet let alone the tip of the drooping nose. Rear three-quarter vision is poor because of the up-swept tail, and dirt soon collects on the heavily canted rear screen. The headrests and reflection from the chrome strips at the base of the facia don’t make matters any easier.
Two door mirrors assist the dipping interior one, which is just as well as the rear view is constantly changing due to the considerable pitch movements. The  enormous anti-lift wipers do their job well but leave a large unswept area in the bottom left-hand comer of the screen.
The lights are fantastic; with the powerful swivelling beams in action no car comes with better lights, though the big glass windows that encapsulate them need regular cleaning. Again, the attitude of the car, particularly the tail droop under acceleration, badly effects (sic) the aim of the beam. The suspension’s self-levelling system doesn't compensate quickly enough to prevent this snag.

INSTRUMENTS ***
Citroen have perhaps been too concerned with symmetry rather than easy reading; the warning light cluster, for instance, is hidden behind the rim of the steering wheel and the oval speedometer is graduated in 5 mph steps and is not easy to read at night. We doubt if anybody would have time to make use of the stopping distances that are calibrated alongside the speeds. A useful gimmick however, is the button with which you can test all the major warning light bulbs.
The auxiliary instruments, including oil and water temperature gauges and the fuel gauge, are set into the lip of the facia and angled towards the driver. All instruments are illuminated with subtle green lighting at night. On our test car the water temperature needle would sometimes move into the red zone before the fans were heard to cut in.

HEATING ****
Heating is easily controlled. One horizontal slide regulates temperature, one distribution and a third the volume, including a four-speed fan. Not only is it immediately obvious how to work the heater but it all works very well, providing fine control over a powerful set-up. Our only quibble is that it would not demist the screen as quickly as we'd like.

VENTILATION *****
Our test car was fitted with the optional air conditioning so getting cool air was no problem. The fan can be used to force ample air out of the multi-position centre vent and thus assist the effective ram system of the eyeball vents at each end of the facia.

NOISE ***
It seems reasonable to expect peace and quiet in a car of this quality and price. In this respect the SM has a Jekyll and Hyde character.  Wind noise is very low with no more than a hiss building up around the exterior mirrors and the seal at the front of the doors. Road roar, is disappointingly high, though, and there is also a fair amount of bump thump. The worse offender, however, is the engine, which makes a nasty rattly noise when idling, a loud induction roar on full throttle and a high-pitched whine when nearing peak revs. Only when cruising in fiffth is engine noise unobtrusive. Other infrequent rattlings would appear to come from the hydraulic pump, though it is not as obtrusive in the SM as it is in the DS.

EQUIPMENT ****
The SM has most of the amenities you would expect of a car of this type and price, plus one or two rather unusual ones. Electric windows, reclining seats, power steering and headrests are standard. There is a central ashtray with built-in cigar lighter and two more ashtrays at each end of the back seat. There are two fold-out sun-visors with a vanity mirror for the passenger. A clock, heated rear screen and reversing and parking lights are also included.
More unusual are the swivelling, self-levelling lights and, of course, the variable height suspension. Extras included on our test car were the air-conditioning unit and tinted windows. A radio is not fitted as standard.

FINISH *****
The standard of finish is high and to us very pleasing and modern in design. The brushed nylon seats and combed stainless steel facia emphasise this ultra modern décor which is refreshingly different to that of most luxury cars. Carpets line thee footwells and outer sills as well as the floor itself. A coarser-grained one used to cover the interior of the boot and the spare wheel.
Outside, rubber inserts in the wrap-around bumpers help prevent those odd dents and scratches. The paintwork didn't look very durable in places though, some of the (unstressed and replaceable) panels being thinly covered at the edges.

SERVICE
With its new fuel injection system the SM’s engine is practically invisible. The long inlet tracts swoop over it, completely obscuring the sparking plugs. Even the dipstick is hard to find, hidden away at the back of the engine under the long bonnet. Certainly the mass of pipes, hoses, pumps and reservoirs that together fill almost every square inch of the engine compartment will be more than enough to dissuade the average owner from getting his hands dirty. Even the battery looks as if it is cocooned for life.
However, when you've worked out where they are, you can at least get at the oil filter, the hydraulic reservoir and the radiator header tank.
The spare wheel is located in the boot together with the accessories required for jacking the car up. There is no twiddling of handles with the Citroen; the hydropneumatic system does all the work.