At a time when the marque was generally pilloried by the majority of the UK automotive press, Car stood alone in its appreciation of the double chevrons.

The Ro80 was unveiled at the 1967 Frankfurt Motor Show and went on sale in 1968.

It was fitted with the Wankel rotary engine manufactured by Comotor, a joint venture between NSU and Citroën.

The same engine was also fitted to the GS Birotor.

The BMW 520 was launched in 1972 and offered very little innovation - rear wheel drive and very traditional styling.

So how did this eighteen year old design stack up against its much more modern rivals?

ALTHOUGH WE HAVE BEEN CRITICAL of the BMW 520's pricing, it is not as outrageous at it first seems when you consider that the NSU Ro80 has been hovering around £3000 since last year, and that the latest 2.3 litre Citroen DS gets close to that figure when it's wearing Pallas trim. In context with its rivals, each member of this Giant Test trio makes more sense than it does in isolation, but that is hardy likely to cure the severe shock to the wallet that is associated with parting with £3000 for two-litres and four cylinders or in the case of the NSU, for a journey into the partly unknown.
The BMW is the newest of the group. Not as new as the 'all new' claims of the manufacturer, but newish nevertheless. Theoretically the 520 is a replacement for the much cheaper, thoroughly outdated and extinct 2000 range. The main carry-over is the engine, albeit modified. In its present role, the 520 fits in between the 2002Tii and the 2500 saloon; it's no secret that the six-cylinder 2500 engine will soon find its way into the 520.
When someone had to carry the banner for the Wankel engine it was NSU who made the Ro80 the rotary showpiece. But it was plagued by major difficulties that are almost sufficiently sorted out for the vehicle to now be considered just practical; NSU are very fast indeed to sort out difficulties arising from engine malfunction and offer an unusually long warranty period which does at least give the owner some measure of security.
The Citroen is a healthy child of the evolution. It has been refined and improved mechanically and stylistically since the mid-fifties and continues to get better. Each successive Citroen DS is predictable only in that it will be a better model than the last, incorporating innovation where and as necessary, but never merely for the sake of it. The staunch individuals who have been responsible for the DS's growth don't play at childish compromises; when they have decided that a certain course is the correct one, then that's the line they follow and the product's buyers had better fall into step. Of course, this almost high-handed attitude is right: one pays good money to have a car designed by experts, not by amateurs.

STYLING, ENGINEERING

Both the NSU and the Citroen are familiar shapes-and the BMW is almost familiar. It wears a completely new body but is not a substantial departure from previous BMW designs, being a slightly scaled down three-litre in size and not spectacularly different from it aesthetically. The German firm cling to their traditional radiator shape with an ease that is denied other firms who try to link the old with the new.
Of course, the Citroen does not have a grille to worry about. Its shovel nose has evolved progressively, just as its headlamps have blended into the wing contours as the years have progressed. In this way, the DS is the epitome of a streamlined car, having the profile of something that is not entirely automobile; it's not weird, not any more, but it's by no means outdated, either. The back wheels being so far astern label the DS immediately as having front drive.
The NSU Ro80 is front-driven, too. Its concept is that of a flying wedge, the nose being shallow and not as extreme as the Citroen's, whereas the rear gets higher and more pronounced before abruptly terminating. No major changes have been made since its inception.
Of the three, the NSU is the best looking and much more in the spirit of the 'seventies, even though it is a 'sixties car. But it is the Citroen - basically a 'fifties car - that looks to be the most functional of the group, the most relentless and developed not only of this trio but of all current cars. The BMW is a middle-course shape, designed neither to greatly please nor to offend merely by looking like a BMW its position is invulnerable commercially. Of non-revolutionary cars, the BMW stands secure stylistically although it fails to turn over a single new sod of the firm ground on which it stands.
But in a sense revolution and counter-revolution is what this Giant Test is all about. The two older cars represent the revolution that succeeded at least in part while the BMW 520 is the counter- revolutionary example, also successful but for different reasons.

The Citroen was a highly controversial car when it first appeared but all that has died down now. Into the breach has stepped instead the Ro80 as a sort of sacrificial car on the altar of revolutionary ideas. The problem from the word go has been engine durability, and although this has been tediously sorted out until it is at roughly the lowest acceptable level (using reciprocating engines as the yardstick), NSU steadfastly stick by their warranty and replace defective engines without a quibble. Mind you, if they had not done this, the Ro80 would have long ago become an extinct species.
For all intents and purposes the Ro80's Wankel is a two-litre engine. lt develops 115bhp at 5500rpm with 117lb/ft of torque at 4500rpm. It uses 9.0 to one compression ratio and a pair of Solex carburettors. The drive is taken through a three-speed gearbox with a fluid coupling and micro-switched (from the gear knob) clutch action like the VW/Porsche/GS arrangement, to the front wheels. This gives the engine, artificially, the flexibility that would be lacking in a purely mechanical drive train. Top is a direct ratio and gives 18.6mph per 1000rpm.
The chassis of the Ro80 is advanced to match the engine, unlike the Mazda RX-3 which is an engine of great attribute in desperate need of a proper chassis. The NSU uses disc brakes back and front and ends up with a swept area of 458sq in, which cannot be bad on a 28001b car. Steering is rack-and-pinion and is almost imperceptibly power-assisted; 3.7 turns from lock-to-lock for a 39ft circle does not set any new records. Suspension is independent coil back and front and provides long wheel movement at the same time as giving a well-controlled ride.
Of course, the Citroen is front-driven as well, by an engine that is really an extension of the unit that first powered the DS series. In other words, a pushrod four cylinder with a crossover pushrod arrangement to give hemispherical combustion chambers. In its latest guise the engine displaces 2347cc from cylinder dimensions that give a 93mm bore and a 86mm stroke. On the model as tested the power output was 130(DIN) horse-power at 5500rpm with 148lb/ft of torque at 40O0rpm due to the use of Bosch electronic fuel injection. Compression ratio is 8.75 to one. The drive goes to the front wheels via a five-speed manual

gearbox mounted ahead of the engine and the front-axe line. Optional is a four-speed, semi-automatic transmission. Brakes are disc at the front and drum astern and give 345sq in of lining area in a car that weighs 28661b at the kerb. Both the brakes and the steering are power-assisted from a central high- pressure hydraulic system that also links in with the self-levelling, oleopneumatic, all-independent suspension. The turning circle is 36ft (good for a front-wheel-drive saloon) but more important is the fact that the wheel requires only three turns lock-to-lock, reflecting Citroen's demonstrated belief in the rightness of high-geared steering. Remember that the SM needs only two turns lock-to-lock and Citroen's design engineers consider even that to be too low-geared.

The BMW is not in the position to make great claims to ingenuity. Instead, it is a well-developed design that has stamped out the criticism that has been levelled at both the three-litre models and the 2002 series, the old 2000 range being beyond the point where criticism could hep. In terms of power, the 520 falls exactly mid-way between the 2002 and the 2002Tii at 115bhp(DIN) at 580Orpm with 119lb/ft at 3700rpm. It runs on a compression of 9.0 to one and is fuelled via a pair of Stromberg carburettors that give better emission control than most types. There is now also an injection edition of this engine that provides more performance and power as we as greater smoothness. With a bore of 89mm and a stroke of 80mm, the 520's engine is dimensionally the same as the 2002 range and the 2000 that went before it. The basis of its success is its general cleanliness and the use of a singe overhead camshaft to operate the valves through short rocker arms. Drive is to the rear axle through an all-synchromesh, four-speed gearbox, the direct top of which gives 17.6mph per 1000rpm against the DS's 22.4mph per 1000. Brakes are a disc/drum mix with a swept area of 325sq in for the car's 27001b kerb weight. Steering is manual only and needs 3.7 turns for a turning circle of just under 34ft. Suspension is, naturally, independent all round by coils and trailing arms at the rear with much better geometry than that found in the 2002; at the front the Macpherson type struts are tilted 12deg rearwards with the springs offset in relation to the damper centreline. It's all good stuff but not exactly dramatic, any of it. The important thing is that it works and works well, as we shall soon see.

Physically, the Citroen is the biggest vehicle at 15ft 10.5in overall, sitting on a wheelbase of 10ft 3in, the Ro80 is next at 15ft 8in on a wheelbase of 9ft 4.5in; the BMW is noticeably shorter at 15ft 2in with a wheelbase of 8ft 8in.

PERFORMANCE

The outlay of £3000 is not the guarantee of lots of performance. There are smaller and cheaper cars that will comfortably blow the hubcaps off these three, yet all provide very different performance. For sheer smoothness and general unobtrusiveness, the Ro80 is incomparably good. It simply hums along with an audible warning built into the tachometer to guard against the over-revving that can so easily occur. So unobtrusive is the engine that it is possible to overlook top in built-up areas and charge obliviously along in second. However, performance away from low speeds is uninteresting, the rotary showing its true worth high up the rev scale. Nevertheless, it is smooth and has perfectly adequate performance most of the time; just that it's not a charger away from the traffic lights in the way that the BMW gets into it for example. Fuel consumption in the Ro80 is poor but slightly more forgivable because of its 8 gallon tank capacity. However, 16 to 18mpg is depressingly normal consumption for run-of-the-mill commuter motoring. The torque converter between the engine and the gearbox overcomes the problem of flexibility in this generally peaky engine, so that around town one has the advantages of automatic transmission at the same time as full manual control over the three speeds. So don't buy a Ro80 if, a) you like blasting away from the traffic lights or, b) you consider fuel consumption to be important. Buy it, though, if you place smoothness and easy cruising high on your list. The Ro80 has no particular objection to cruising at 100 or a bit more, and it is so fussless mechanically that one tends to make use of this potential almost inadvertently.
Citroen's DS23 is a fast cruiser, too. In fact, it is one of the quickest open road cars on the market, being happy to thunder along in fifth gear at 115 to 120mph all day long. But the drawback is that the engine is harsh and rough; there's absolutely no question of it coming apart - it's been proven for far too long for that to happen - just that roughness is old-fashioned now. One comfortably runs to 100 plus in fourth before reaching for fifth and letting the Citroen get into the great loping stride that eats up countries like most cars eat up miles. All five gears are high ratios and reasonably close so that one needs to work the engine to get results. Standing-start acceleration is not startling, but the engine and transmission seem to be balanced to keep the acceleration coming on all the way through to a 100 or so when things taper off a little. That fifth gear is not strictly an overdrive, either, for despite its ratio the engine - a real slogger if ever there was one - will accept it as low as 30mph.
Somewhere between the other two lies the BMW 520. That makes it a better all-rounder, for although lacking the Ro80's smoothness and the Citroen's high-speed cruising potential, the 520 is nearer the universal car. It has low first gear that ensures ample acceleration from rest, and enough mph per 1000rpm to provide 100mph cruising, but with the tachometer well around its dial. The engine is not as smooth as the Wankel nor is it as rough as the 23's, which makes it a normal car for normal people who want normal motoring. Most things it does well, including giving good fuel consumption, although it stumbled badly by being unexpectedly noisy in the zone between 4000 and 5000rpm - right where the moderately law-abiding British motorist will want to plant the tachometer needle. To nail it down more precisely, the BMW is fast but has less top speed than the Citroen and little of the smoothness that is the hallmark of the Wankel.
To judge the performance of these cars one must be completely certain to take into account the sort of motoring you intend to do, for this is one of the cases where performance figures are largely meaningless on their own.

TUNING POTENTIAL

Basically these are cars that do not lend themselves to modification, since they do not have sporty aspirations and in the case of the Citroen and the NSU have at least one factor working against any attempt at modification for more performance.
The Wankel engine of the Ro80 is a tippy-toe affair that is still finding its way, and although we have heard of performance-improvement kits being sold in the US for the Mazda rotary, we know of nothing that's available for the genuine and original article. Already the Citroen is quite highly tuned and any effort to go deeper would involve removal of the electronic fuel injection, since modifications would almost certainly be incompatible with the system's printed-circuit controlled calibrations. There's more hope for the BMW. The German Alpina firm, now well represented in this country by BMW Concessionaires, have oodles of go-faster goodies available for the entire range. But perhaps step one is to order the injected version of the 520 in the first pace and pick up its different gearing and additional 15 bhp. 

MAINTENANCE AND SPARES

Because of its hydraulics, suspension and fuel injection system the Citroen is the most complicated of the trio, but it's also the most thoroughly developed which thus ensures that any problems that do arise are unlikey to be brand-new ones. Citroen have set themselves up with a comfortably-sized and secure looking dealer network around the country and back it with a spare parts system that seems to work. The Citroen is not a DIY car, apart from routine servicing of spark plugs and such; major jobs require special machinery, tools and techniques. But then one assumes that a person paying £3000 for a car will be sure enough of his income to have it properly serviced, anyway. NSUs are handed by the increasingly healthy Audi dealer network. Since the German masters are extremely anxious to keep the Ro80 as a viable proposition in this country, they spare no effort to please the customers. But as with all German cars, spare parts and service are expensive.
This applies to the BMW, too. It is backed by a very strong dealer organisation that has been the cornerstone of the successful operation of BMW in this country. It works well - better than most, in fact-but the customer pays for it, generally without flinching.
None of these cars are cheap to operate, due either to a fair degree of mechanical complication or to the fact that they are backed by expensive organisations-or both. 

HANDLING, STEERING, BRAKES

A buyer who plonks £3000 on the line has the right to expect that his purchase will have good dynamic qualities. He is unlikely to be disappointed in any member of this group.
The Citroen, however, is an acquired taste. Drivers don't leap behind the wheel, roar off and fall in love before the fourth gearchange. DS Citroens are not like that. To start with the steering is odd, although light and easy to use. Being high-geared and coupled to traditional Citroen responsiveness, it almost invariably proves too quick for most people when they start off. There's not a great deal of feel, either, and the single spoke of the helm hangs diagonally. The DS has a lot of road-holding, its 180-15 Michelin XAS tyres keeping a firm hold of the road and finally developing an understeer when the driver eventually reaches the rather distant point at which the car nears the limit of its adhesion. Its particular dislike is the slippery downhill corner.
There is some body roll on tight corners but even so the Citroen provides a feeing of curious isolation, an almost unworldly sort of motoring in which the car spends most of its time working with, rather than against, the driver once the oddball factors have been accepted. The brakes are initially nerve-wracking, but reassuring when an understanding has been reached. There is not a pedal as such; just a button on the floor between the accelerator and the clutch. A slight brush with one's right foot is enough to halt the DS, but the trick is to differentiate between what is a brush and what is a jab. The danger exists that the driver will stamp on the button in moments of crisis; if he does the car will lock its wheels in an instant and that will be that as far as graduated braking is concerned. This is not a car that one learns to drive properly overnight, or in a week; it's more long-term than that and it is significant that owners rarely revert to normal cars.
Drivers who are slow to adapt to change may never really come to enjoy the DS23, but they will fall into step with the BMW 520 readily enough. Its conventional rear-wheel-drive makes the car feel and behave very normally without the quirks that the inflexible are likely to misconstrue as vice or malfunction. The first impression of the BMW is that the steering is too heavy when parking and at low speeds; the 175-14 tyres put a lot of rubber onto the road, making the friction so great that moving in and out of tight spots calls for some effort. Once under way, though, the steering is light and quite accurate with the car maintaining a substantially neutral attitude while cornering. The suspension tends to hold the 520 down firmly when motoring hard, and the whole device imparts a feeing of security that can only be fully appreciated when the car is really hurled at corners; it has a tremendous amount of roadholding that is readily available and quite unspectacular. Only those without soul - or £3000 - could fail to be impressed by the 52O's substantial grip on terra firma and its extremely good handing. Less satisfactory is its stability in crosswinds; it moves around far too much for comfort and does not hold a candle to the Citroen or, to a lesser extent, the NSU.
Full credit must go to the Ro80 for its steering. Although power-assisted, it is not specially light and in consequence makes itself obvious only when parking. For the rest of the time the steering is as near to perfect as one is likely to encounter this side of £600O, being accurate and sensitive with the final strong understeer manifesting itself only at the extreme ragged edge of the roadholding - an area not likely to be uncovered by many owners. The soft suspension allows more roll than in either of the other two cars, but is not intimidating or even likely to be noticed by the occupants. There is, too, a tendency when driving the Ro80 to grossly underestimate the cornering potential; not a Bad Thing, for engine braking is minimal and it cannot be a Good Thing in any front-wheel-drive car to be still braking when the corner begins.
Apart from the operating peculiarities of the Citroen all three cars have highly effective braking systems that are positive and will stand continuous hard useage without fuss. Our sole reservation is that the DS23 driver has to be on guard against leaning too heavily on the floor button. In the wet or on snow it could result in the Citroen becoming a big handful indeed. 

RIDE AND COMFORT

We have said in the past that the BMW 2002 was too firm in its suspension and that the three-litre was too soft. Well, the 520 is just right. It falls neatly between the two types and gives a well-controlled, reliable sort of ride that is not exceptional, merely very good. The seats are firm, comfortable and not very well shaped, although the standard of accommodation is generous, dimensionally exceeding the three-litre in some areas. The front seats go through the motions of being contoured, but they don't grip in the right paces so that one is left free to wobble about. Nor is it a particularly quiet car, both engine and windnoise being obtrusive at high speeds, although a concerted effort at the factory should be able to overcome this in short time. Road noise is a conspicuous absentee and although the fan for the ventilation system is remarkably quiet, the air gushing into the cabin through the large central vent makes its own roar. Some internal smoothing should help overcome that.
The Citroen's suspension is still not really lacking after all these years. It's smooth, reasonably quiet, automatically adjusts to its correct ride height and, of course, can be raised and lowered at the will of the driver to give maximum terrain clearance and to aid in wheel changing. It's a great float-along-with-us system that is complemented by seats that don't need much shaping because they are soft and the occupants sink into them. Not that the springing is perfect, for sudden sharp undulations (hump-back bridges, for example) throw the suspension in confusion so that the vehicle lands uncharacteristically hard. Engine noise is obtrusive at high engine revs but not so bad cruising at around 4500rpm in fifth. Wind noise is we suppressed-better than in Citroens of only two years ago, in fact.
Not only does the NSU Ro80 have the best seats, but its suspension is also superior in its ride to that offered by the BMW or the Citroen. The shaping of the seats is more realistic than in the 520 beinq, if anything, more homey. To the Ro80's score must also be added the quietness of the engine and its minimal wind noise, although road noise has not been eliminated. The long wheel travel provided by the NSU'S suspension allows it to cope admirably with all kinds of surface, so that the ride feels more French than German most of the time-which is a compliment in case you were wondering.
All three cars have good ventilation systems, but it would be nice to see the BMW with a greater input of fresh air for summer weather - a condition for which the Citroen seems particularly well suited. The members of the trio have the comforts one would expect in this class of vehicle: heated rear windows, carpeted floor, wide range of seat adjustments, armrests in the usual places, ample luggage space and plenty of small-items stowage space. There's nothing elaborate about the BMW'S cabin - it's plain, but not stark - while the other two are slighty more contrived. With the Pallas trim, the Citroen has excellent cloth upholstery and the NSU uses a mock velvet which is the alternative to perforated vinyl in the BMW. The carpet in the German cars verges on cheap-looking (no doubt very durable), whereas the Citroen's looks the part and is underlaid with foam to give the floor a soft, deep feeling. 

CONTROLS, INSTRUMENTS

Citroen have rationalised the DS's instruments to a practical minimum, then backed this up with an immensely sensible warning system. There is a tachometer and a speedometer facing the driver as well as a fuel gauge, while the third major face is an enunciator panel that carries all the warning lights; those for hydraulics temperature and oil pressure operate in conjunction with the large, glaring 'stop' sign. A check button enables the driver to establish that the circuits are functioning. Citroen have steadfastly stuck to steering column gearchange for the DS models and it works so well that there would appear to be little advantage in moving it to the floor-except for reasons of fashion, which have never interested Citroen, anyway. The handbrake is mounted under the dash and is hard to reach unless the driver is unbelted (shudder) or is wearing an inertia-reel harness. Minor controls are worked by three steering-column stalks and it s worth noting that Citroen still insist on manual-cancelling winkers.
The BMW'S instrument display is superbly arranged but reveals no more than road and engine speeds, fuel contents and engine coolant temperature. Steering stalks control the minor functions, although the lights have a masterswitch on the dashboard; the wipers have two normal speeds and an intermittent sweep. There is also an expensive quartz clock on the dash. Floor-mounted, the gearchange works we enough but is still not as positive as one could reasonably want. Handbrake is between the seats.
And so it is in the Ro80. Its gear-change lever is a bit vague, too, and not within easy reach. Like the BMW, the NSU has two-speed wipers plus an intermittent sweep, and most of the minor controls are steering-column located. Besides the very neatly calibrated tacho and speedo, the Ro80 has gauges for fuel contents, engine temperature and oil pressure.
The really impressive thing about all three cars is that the control systems have been very well thought out and so neatly done that none are likely to cause any potential buyer disappointment. All have good lighting systems, but the Citroen caps them all with auxiliary lamps that swivel with the steering. 

CONCUSIONS

We would love to love the NSU Ro80, but all the time there would be this nagging doubt in our mind about its durability. Sure, the factory have shown themselves as being jolly decent types by super-honouring the engine warranty and there is no doubt that the Wankels are getting better day-by-day, but it would be a bit like marrying a reformed husband-poisoner. The car's obvious qualities are so good that anyone with £3000 in his pocket should feel no shame in attempting a flirtation for reasons of smoothness, comfort, styling, suspension and, even at this late stage, pioneermanship!
Less likely to win applause are the Ro80's high fuel consumption and mediocre performance against the stop-watch. It is, however, a far better car for home-counties' commuters than either of the other two.
Then, of course, there's the Citroen. A great car for fast touring and one that can be relied upon to behave perfectly in bad conditions, but can feel awkward around town because much of the nose is invisible to the driver and invites itself to be buried into the boot of the car in front. Light to drive, very comfortable indeed, fairy economical but with an engine that is rough and controls that require a driver new to Citroens to alter his thinking, the DS 23 is a car that needs to stretch itself. Given that circumstance, it is a fantastic vehicle.
That leaves the BMW. Yes, our choice, but with reservations. For one thing the steering is too heavy, the engine is not specially exciting nor is the everyday performance. Handing and roadholding are tremendously good even if the cross-wind stability is not; it lacks the character of the other two but makes up for that by being the best a-rounder if you like down the middle motoring.
The lasting impression that we gained from these cars is that a buyer is unlikely to be unhappy with any of them. All three are very good examples of what motoring is all about, but it is the BMW that has been compromised-too much it can be argued-in the cause of far-reaching versatility.