Drive-my road test drive Citroen CX2500D vs Peugeot 505GRD and Renault 20GLD. Diesel cars come in two types: frugal small cars (like the Golf) and big saloons like the three here, with engines larger than 2.0 litres, comfort and performance. We compare Citroen, Peugeot, Renault. The British market remains stony ground as far as diesel car sales are concerned. Every time a Chancellor brings in a tax differential to favour heavy oil, a petrol war seems to break out with the result that derv remains discouragingly more expensive than four-star. Whether this state of affairs will persist is open to doubt; and it is a fair bet that if ever the pump price of derv becomes significantly cheaper than that of petrol, a lot more motorists will sit up and take notice.
There is a lotto be said for any combination of cheaper fuel and better economy. There is even more to be said for it when the quality of the latest generation of diesel-powered cars is taken into account.
It used to be assumed that diesel cars were slow, noisy and unrefined. When “diesel cars” meant the Peugeot 404D, the earlier Mercedes diesels and a handful of Perkins-propelled beasts from BMC and Rootes, it was a reasonable assessment. Like so many things, the major change was wrought by the energy crisis of 1973/1974. In countries where petrol was very expensive and derv was relatively cheap, diesels suddenly made sense not just for taxi operators and high-mileage motorists, but for almost anybody who did a reasonable annual distance and/or spent most of his driving life in heavy traffic. In short order, Mercedes and Peugeot found that their taxis were in great demand. The trend was too strong to be ignored by other manufacturers and we have now reached the point where every major European company (now that BL have announced the Rover Turbo) offers a diesel. The main strength of production however still lies in France and Germany. Peugeot’s diesel expertise is now available to the PSA group as a whole, while Renault have moved quickly to plug their diesel gap with versions of the 18 and 20.
Original test-drive foto 1982
Thus far, diesel cars have fallen very much into two classes. The more numerous is composed of the traditional taxi-types: roomy saloons with engines of around 2.0 litre capacity. The more technically difficult business of making altogether smaller cars, led by Volkswagen with the Golf, is now gathering momentum, but it is among the larger cars – such as those which are tested here-that the range is wide and the choice potentially difficult.
STYLING, AND ENGINEERING
Peugeot’s long-standing support of diesel power has been most clearly expressed in the string of long-lived models stretching from the 404, through the 504 to the current 505. For a long time Peugeot’s own tough but elderly power unit was used, stretched in capacity from time to time: through 2.1 litres (in which form it was sold to Ford for the Granada) and finally to 2.3litres.
This last move was something of an ultimate stretch and it was not long before the PSA controllers realised that the next logical step was to adopt the 2.5 litre diesel developed by Citroen for the CX and adapt it to give the 505 a further performance boost. Thus two of our test cars have essentially the same engine, a virtually ‘square’ OHV unit of relatively high compression, a capacity of exactly 2500cc and respectable power and torque output.
Lacking an in-house diesel small enough for car use, Renault elected to carry out a crash programme of their own when the need became clear. They adopted as their basis the all-alloy 2.0litre engine produced at the joint-venture Douvrin plant – an engine which in petrol form also powers the Peugeot 505 and Citroen CX. With its taller block and new cylinder head, the diesel is Renault’s alone, though: compared with the Citroen/Peugoet unit it is substantially smaller in capacity (at just under 2.1 litres), runs a lower compression ratio and produces less power and torque.
Original test-drive foto 1982
The engines are installed in three different ways. While Citroen and Renault (inevitably) drive the front wheels, Peugeot stick to the classical rear-drive arrangement. In the Citroen, the same engine is installed transversely. The Renault 20 cantilevers its engine in-line, ahead of the front axle line, well forward in the long nose. All three cars take the drive through a manual five-speed gearbox. One of the things which has helped to make diesel cars far more acceptable is the way people have realised that five speeds are needed if the narrow power band of the compression ignition engine is to be spread widely enough.
Just as the engine installations are different, so are the cars themselves. As befits its conventional drivetrain, the Peugeot 505 is an extremely conservative three-box saloon. Its chassis engineering is equally conservative: nothing new, merely an intensive refinement of the 504 layout with MacPherson strut front suspension and semi-trailing arms at the back. The Citroen swings to the other extreme, its smoothly aerodynamic shape looking as advanced today as it did when the car was launched eight years ago. As always, Citroen pin their faith on radically different engineering. An engine-driven pump feeds the power for the hydropneumatic suspension, the steering and the brakes (not for Citroen the need which faces every other converter to diesel power to throw away the vacuum brake servo and engineer a new system).
Renault’s 20 leans towards the Citroen shape, but for the very practical reason that it is a slope-tailed hatchback, the only one of the three to offer the fifth door. In other respects its engineering is conventional with the possible exception of its oddly complicated rear suspension, designed to overcome the drawbacks of a simple semi-trailing arm layout.
It is still true: diesel-powered cars are slow. On the other hand they are certainly not unbearably slow, and by the standards of 10years ago they would be considered respectably quick, if these three are anything to go by. This is especially true of the Citroen and Peugeot which have the power and torque advantage conferred by an extra half-litre of engine, and carry no more than a hundredweight of handicap compared with the Renault.
The differences between the Citroen and the Peugeot are inevitably small. When two cars have the same power unit – even if Peugeot for some reason of exhaust system efficiency claims an extra 10 bhp at a slightly higher peak – and have much the same overall gearing, and differ in kerb weight by a quoted 33lb in something like 26cwt, the story could hardly be otherwise. All that remains to explain any discrepancy is the spacing of the gears (the Peugeot’s third and fourth being notably higher) and the advantage which the Citroen should enjoy in lower aerodynamic drag at higher speeds. The odd thing is that our Citroen and Peugeot returned identical maximum speeds, 98mph in either case. This is not what conventional wisdom would suggest, but there is a clue in that the Peugeot’s maximum is achieved almost exactly at the power peak, while the Citroen pulls a short way past. This suggests that the diesel’s power falls off quickly once the peak is passed – an assumption borne out by the fact that our best acceleration times were achieved by changing up well before the high-speed governor came into operation.
If you bear in mind that the Citroen and Renault were both in fourth gear by the time S 60mph was reached, their acceleration times look far from bad, while at the same time the basic reason for their economy becomes clearer. It also underlines the fact that a good driving rule for any diesel is always to be one gear higher than you would in the petrol equivalent. With a good spread of five gears, diesels like this no longer suffer from the awful choice of whetherto be under-geared in top or to settle for awful gaps between ratios. It isn’t difficult to keep any of the three feeling ‘on the cam’ although it calls for some very quick gearchanging when pulling fast away from rest. At the other end of the scale, fourth gear can still pack a punch of sorts – especially in the Peugeot where it runs to well over80mph.
The Renault is not as quick as either of the PSA cars, which is hardly surprising in view of its lower power-to-weight and torque-to-weight ratios. In an effort to overcome this, Renault have geared the 20 lower than the others, and one result is that the car has a significantly lower maximum speed: its 93mph is achieved (again) right on peak power. At the same time its lower effective maximum speeds in the gears – especially the three lower ones – still leave it with something of an acceleration deficit.
The real name of the diesel game is economy. Here it must be borne in mind that the diesel gains far more, compared with the petrol engine, in some situations than in others. The diesel is at its most efficient when working at part-power, unlike its petrol counterpart which works best with the throttle wide open. It followsthatthe diesel fares best in the classical taxi environment of dense traffic and moderate speed, while its advantage is whittled away in high-speed motorway cruising.
This was certainly borne out by our test cars, which showed an uncommonly wide spread of consumption according to the way they were driven. Again as one might expect, there remained little overall difference between the Citroen and the Peugeot- you would hardly expect much difference in fuel usage over an extended period from two cars with similar weight, power unit and performance. The Citroen emerged marginally superior, probably because its consumption suffered less in 85mph motorway cruising – those aerodynamics have to play their part somewhere. Around town either car would push 40mpg and no doubt a determined economy effort would take you somewhere past that. The Renault emerged less well. Overall, it achieved nearly 3.0mpg worse than the other two. Like them, it spent a fair part of its test life at high speed, and here it was noticeable how much more often it needed full throttle (or to be strictly diesel- accurate, full fuel) to maintain a high motorway cruising speed. In any case it is logical to expect that below a certain power- to-weight ratio, a diesel car will spend more of its time at full throttle and sacrifice some of its notional economy advantage. Our results suggest that for quicker drivers at least, the Renault is below that break-point while the Citroen and Peugeot are on or above it. That is not to say that gentle driving might not get better results with the smaller-engined, somewhat lighter Renault – but the choice does require you to know what sort of driver your really are.
An incidental advantage of diesel economy is that you enjoy exceptional unrefuelled range. This is especially true of the Citroen, whose 15gal tank means that very little restraint is needed to achieve 500 continuous miles. The Renault’s tank is almost as large; the Peugeot holds only 2.3gal, but this should still suffice for over 400miles of almost anyone’s driving.
HANDLING AND ROADHOLDING
One problem with any diesel engine, seen as a replacement for a petrol engine, is that it is heavier. Renault, for instance, quote a weight penalty of 80lbs for their diesel, one which is likely to be less than most. It follows that with the extra weight over the front axle, the steering will be heavier and the handling balance will be altered.
The steering problem is at its most significant in cars of this size where the effort/gearing compromise is getting a bit tense anyway. You can except Citroen from this argument because the CX is power- steered as standard in any case; Peugeot and Renault both settle for standard power- assistance with the diesel. The steering, naturally enough, is rack-and-pinion in all three. Adopting power assistance means that the steering can be made fairly quick – the Peugeot is the most restrained, with 3.5 turns of the wheel between 35ft locks – and this has the extra advantage of helping to cover up any nose-heaviness resulting from the engine change. The extra weight isn’t enough to force a change of tyre size, the Renault 20 stays with its 165-14s, the heavier Peugeot on its 175-14s, while the Citroen runs 185-14s at the front but keeps 175-14s on its lightly-laden back end.
The differences in handling are there, but are small enough that you are hard put to notice them without running a back-to-back exercise with the petrol-engined equivalents. The Peugeot and Renault understeer a little more, squeal their front tyres a shade more readily close to the limit; that is all. In the Citroen, where the Varipower steering so effectively blurs conventional driving assessments anyway, any effect goes totally unnoticed.
In absolute terms, the Peugeot remains the pick of the bunch. It is so well-balanced and forgiving a chassis. Normally it -understeers in moderation, but it can be “thrown” into neutral steer and will hold it round the right kind of corner as though its ‘acing pedigree was of the highest. Lift off, and the understeer slows it down: just that, without any show of temper. The Renault is what you would expect a big, front-driven car to be. Under any sort of power it -understeers. Clumsy driving – lots of power and a quick handful of lock-can see it understeering a great deal. Lift off, and the handling is very nearly neutral while it lifts its tail and slows. The Renault is safe and its limits are high, but it doesn’t flatter one’s driving like the Peugeot. Then of course there is the Citroen: razor-sharp steering, instant response and only 2.5 turns of the wheel between locks. The big CX understeers at any time – and usually more than the steering lets you know. The most reassuring thing is that the tail never lets go. The true secret of CX driving is to take care of the front end, as much with power as with steering. The back takes care of itself.
Both Citroen and Peugeot are generous with brakes. The Citroen has discs all round, plus the feather-lightness of its system which takes even more getting used to then the steering; the Peugeot has huge 10in drums at the rear to back up its even bigger front discs. By comparison the Renault looks almost under-braked; but it is the lighter car and its system is amply capable of coping with diesel performance.
These are three roomy French cars, with all that implies where ride comfort is concerned. The Peugeot offers the least room inside, especially when the front seats are slid all the way back, yet there is still enough combined front and rear legroom to qualify it as a comfortable four-seater. The Renault is more generous still, and the Citroen takes the interior space prize, not surprisingly in view of its massive wheelbase and transverse engine.
The Peugeot has the best seating, overall. Its two rivals both fall into the familiar French trap of providing plenty of softness but not enough shape; the Renault lacks firm support in the small of the back while the Citroen lacks enough sideways location for some tastes. All three back seats rate better than average, not only for roominess but for correct angling of cushion and squab for relaxed comfort. The main fault here is the Citroen’s, where the cushion is too low and yet headroom barely adequate for big passengers.
The Citroen and Peugeot have so well established their reputations for a remarkably comfortable ride that it comes almost as a surprise to find the Renault measuring up to them. All three play to the full the French forte of long wheel travel and superb damping. The Citroen remains magical in its ability to soak up punishment from the most appalling surfaces, but at the expense of some float on undulating roads and too little damping in roll through S-bends. Like most front- driven cars, the Citroen and Renault take less than kindly to single large bumps crossed at any speed, unlike the Peugeot which maintains its level attitude and lands gently. All told, the Peugeot is a superb compromise whose only slight weakness is a trace of harshness at low speed. Even this fault is overcome in the Renault, though in return it feels softer in roll.
It could be that one French failing lies in the design of ventilation systems, since both the Renault and (more seriously) the Citroen are lacking in this respect. The Peugeot is better off, not only in its through- flow of fresh air, but also in the ease with which its heater can be controlled to produce the right temperature.
Performance apart, the one nagging doubt in the back of many minds about the diesel is noise level. It should have been said often enough by now but it is still worth repeating: for a split second after a hot start, and maybe five seconds after a cold one, these three cars let you know you are in a diesel. Beyond that-from inside the car at least-they remain almost spectacularly quiet right up to the 90mph cruise. In the Citroen, diesel or not, road noise remains more of a problem.
The Peugeot may be conventional, but that doesn’t stop it offering an extremely large boot, long and wide though not as deep as some. The tape measure suggests there is less room in the Citroen, but against that there is the extra convenience of a layout which consists virtually of a plain rectangluar box with its lip-less floor very close to the ground (and with the spare wheel stowed at the other end of the car to cheat Murphy when he feeds you a puncture with a full load of luggage). The Renault, although the only hatchback, spoils the impression not only by having a fairly substantial lip over which big items must be lifted, but also because, like the Renault 16 before it, its back seat can be converted to a number of unlikely arrangements but cannot be folded to form the now accepted extended load platform.
Hands up all those who ask what driver appeal has to do with a diesel… In fact for the most part, the French manufacturers have accepted that just because a car has a diesel engine, it need not be spartan inside. Peugeot equip their 505 only to the basic GR standard but since this includes cloth trim, a pushbutton radio and most other desirable items short of electric windows, sunroof and central locking, there isn’t much to complain about. Citroen and Renault both offer a choice of trim levels for their diesels, the CX Reflex matching that of the best-selling petrol version, the 20GTD having electric windows and central locking and offering a sunroof as the only major option. Lesson one: diesels are no longer rubber-matted and rock-bottom.
When it comes to driving, the power steering takes most of the hard work out of progress. None of the five-speed gearchanges is brilliant but the Peugeot’s has the most direct feel, and also the most progressive clutch. The Renault and Peugeot both have light, not-quite- progressive brakes which (as always in the Citroen) call for concentration and practice to achieve a jerk-free full stop.
In some ways, diesels are easy to understand and maintain. There is no ignition system to worry about, for a start. Once you learn which pipes are which there is an air of pleasing simplicity about the under-bonnet scene in any of our test cars, most of all the Renault. On the other hand you have to remember that diesels are fussy about dirty oil (because their main bearings are very loaded by comparison with those in a petrol engine with half the compression) and even fussier about water in their fuel (which if it gets through the filter can seize the expensive injection pump solid overnight). So don’t expect to make a saving on service just because you won’t need to buy spark plugs.
The first question is, do you buy a diesel at all? It all depends how you look at things. Taking the price lists at face value, the premium you are asked to pay for diesel economy with these three varies from a modest £355 for the Renault to a whacking £1617 for the Citroen. Before you draw the obvious conclusion, though, it may be worth asking if the £7845 Renault 20TS (the comparable petrol-driven car) doesn’t look horribly over-priced when lined up with the £6794 Citroen CX Reflex. It is certainly open to you to say this is what it will cost you to go diesel rather than petrol if you are a Citroen fanatic, but presumably – pricing policies being what they are-it also reflects the relative eagerness of the two companies to sell their diesels in Britain.
Then again, if you are a diesel fanatic you may ignore the petrol-model prices and simply compare these three cars on their merits. In that case, the Peugeot is the cheapest and has a great deal of merit: comfortable, economical, with good handling and the ability to cruise quietly at 90mph. Its brother Citroen costs £500 more and for all its extra room inside, it is hard for anybody to justify the difference unless the Citroen character as a whole appeals. As we have said ad nauseam, once you are hooked on the CX it is very difficult to live with anything else; but a lot of people sincerely try but never catch the habit.
Likewise, the Renault is hard to sell against the Peugeot. It can justify its extra price in the shape of extra equipment, but its performance deficit is noticeable and its economy can suffer if it is driven to keep up with the others. Nor, indeed, is it quite as pleasant to drive as the Peugeot. On the basis of strict comparison, therefore, the 505 takes our vote.
Peugeot’s suspension compromise is probably best of three; short wheelbase allows lots of manoeuvrability but suspension rates build in comfort and happy geometry looks after tyre adhesion Profile is usual neat, conservative Peugeot treatment, ageing well Facia and instruments are laid out in a good, conventional way Seating is comfortable supportive; initial softness is succeeded by firmness miles on Engine is fairly smooth, car lacks CX top speed Details: Washer bottle is huge; bucket seats are among the finest.
CX 2500D has high adhesion levels, leans quite heavily in hard cornering CX dash is like no other; digital speedo doesn’t suit everyone but controls are fine Cabin room is greatest of three cars; low rear seats bother those with long legs. Citroen shares 2.5 litre engine with Peugeot, has excellent economy Smooth body’s lack of hatchback is embarrassing Boot is roomy but access difficult Details: switch ‘satellites’ are ergonomic achievement; variable height suspension an advantage.
Softly-sprung Renault has plenty of roll in corners, always displays understeer but resists serious scrub until high speeds are reached Ride is extremely good but lacks Citroen’s excellent self-levelling Body lines are well- balanced but have not had great sales appeal. Hatchback is a distinct advantage Facia looks sparse but is best-equipped; has central locking and electric windows Renault’s 2.0 litre engine lacks Peugeot and Citroen power; thrashing it can cost in fuel Details: rear seat folding system can be confusing.
|CAR||Peugeot 505GRD 1982||Citroen CX2500D 1982||Renault 20GLD 1982|
|ENGINE||4 cylinder in-line||4 cylinder transverse||4 cylinder in-line|
|Compression (to one)||22.25||22.25||21.0|
|Valve gear||8 OHV||8 OHV||8 OHC|
|Induction||Roto-Diesel injection||Roto-Diesel injection||Bosch injection|
|Power (DIN bhp/rpm)||
|Torque (DIN lb ft/rpm)||
|Ratios/mph per 1000rpm|
Final drive ratio (to one)
CHASSIS AND BODY
Turns, lock to lock
Turning circle, kerbs
MacPherson struts, coil springs, anti-roll bar
Semi-trailing arms, coil springs
Rack and pinion, powered
10.7in discs front,
10.1in drums rear
All-steel monocoque plus perimeter frame
Double wishbones, links, hydropneumatic coil springs, spring/damper units anti-roll bar interconnected with rear
Trailing arms, hydropneumatic Rack and pinion, powered
10.2in discs front,
8.8in discs rear
Semi-trailing arms, coil springs
Rack and pinion, powered
9,4in discs front,
9.0in drums rear
Fuel tank capacity (gal)
Kerb weight (lb)
CABIN DIMENSIONS (in)
Legroom, front (seatfwd/back)
Legroom, rear (seatfwd/back)
Shouider room, front
Shoulder room, rear
Luggage capacity (cu ft)
Major service time
Sump (capacity/oil grade)
Oil change intervals
Time for removing engine/gearbox
Time for renewing clutch
Time for renewing front brake pads
Time for renewing exhaust system
Number of UK dealers
MECHANICAL SPARES PRICES (£ ex VAT)
Engine on exchange
Gearbox on exchange
Set brake pads
BODY PART PRICES (ex VAT)
Front door (primer)
Headlamp unit (each)
TOTAL COST INCLUDING CAR TAX AND VAT (E)
Price as tested
Model range price span
Length and conditions
SPEED IN GEARS (mph)