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Citroen CX Diesel

First British road test on the diesel version of Citroen's stylish CX saloon. It shares the aerodynamic qualities of its petrol-engined brother but is the loss in performance outweighed by economy of operation?


Autocar week ended 22 January 1977

Equivalent model to CX2200 Super, with 2.2-litre diesel engine.
Little noise or refinement penalty; valuable gains in economy; reasonable performance.
Good stability and steering, predictable cornering and superb ride comfort.
Excess nose weight gives slight tendency to lock up in heavy braking, but brake response very good.
A potentially long-life low cost car of great comfort and spaciousness

OUR RECENT foreign touring number revealed the tremendous difference between petrol and diesel prices on the Continent, particularly in France where diesel costs only about half as much as derv. With this discrepancy in its favour, as well as the potentially better economy, it is astonishing that almost every Frenchman does not run a diesel car, and even more surprising that it was only last year - following a preliminary announcement at the 1975 Frankfurt Show - that Citroen added diesel cars to their range.

Only one diesel unit is available, known as the M22.621, and it is offered for the Safari estate car as well as the saloon tested here. Derived from a Citroen commercial unit first launched in the C35 van in 1975, the engine is an in~line four-cylinder unit with capacity of 2,175 c.c. It has exactly the same bore and stroke as the 2200 petrol engine, but compression is raised from the normal 9-to-1 of the petrol unit to 22.25-to-1. It is a pushrod ohv engine, with high-mounted side camshaft driven by pinion. As for all the CX range, the engine is mounted transversely at the front, driving the front wheels, and leans forward at an angle of 30 deg to the vertical.

In diesel form, the engine_produces 66 bhp instead of 112 bhp (both figures DIN), and reaches peak output 1,000 rpm lower, at 4,500 rpm. The reduction' in peak torque is much less marked, with 93 lb. ft. available at 2,750 rpm, against the 123 at 3,500 rpm value for the 2200 petrol unit.

Bare comparison of performance figures for the diesel give a false impression that it is a lot slower than it proves to be on the road. An acceleration time of over 20 sec to reach 60 mph from rest is on a par with some of the bigger motor caravans, and is getting on for twice as long as the 2200 petrol car takes. By the time the diesel has accelerated through the gears to 80 mph, the petrol version would have reached well over 100 mph.

For many buyers, however, all out acceleration is not a topic for major concern, and we should emphasize that all the time we had the Citroen diesel we were impressed by its relative liveliness, rather than despondent at the sluggishness implied by the acceleration figures.

To a great degree this is due to the sensible spacing of the gears, which allows the best use to be made of the engine, The indirect ratios are all the same as for the petrol car, but a slightly lower overall ratio is produced by use of 13/62 reduction gears to give a 4.77-to-1 final drive against the 2200’s 4.58. Top gear is a slightly geared-up indirect ratio to give a 3.81 overall ratio in top, and an effective 19.3 mph at 1,000 rpm.

Maximum speeds in the indirect gears are 24 (which is on the high side for a diesel car’s first gear), 42 and 66 mph. By the time these limits are approached one can sense that further revving is of no avail and that a change up is due, and this does mean that one can sometimes feel the engine is running out of revs rather early when overtaking in third. If so, the gear change is so good and positive that no effective time is lost in a quick change up to top.

There is a popular misconception of diesels that they produce a great deal of torque at low revs. This is perhaps owed to the type of vehicle for which diesel engines are usually developed, and in a high speed diesel for car use the reverse is true: response at low speeds is somewhat lacking. The car calls for free use of that very sturdy and easily manageable gearbox to get the best out of it. What is noticed is the effect of the heavier flywheel, whose great inertia enabled the car to surprise the testers with a shriek of wheel-spin when making its full power starts from the line. It helps, for smooth progression through the gears, to keep the throttle partly open.

Diesel cars generally have improved greatly in terms of control simplicity in recent years, and the old days of separate start and stop controls have passed. The Citroen is right up to date in this respect, having just a single key control for the engine combined with a steering column lock. For a cold start it is turned first to the warm-up position, which activates the glow plugs in the cylinder head for initial starting. A red warning light comes on to reveal that the pre-heater plugs are switched on, and the key can be left at this position until the warning light goes out.

On one morning of bitter frost, we left the key at this warm-up position while de-icing the windows, and by the time this operation was completed in four minutes, the light was still showing, yet an immediate start was possible and no doubt would have been much earlier. The tell-tale soon goes out once the engine starts, and in more normal weather we found that a 20-second warm-up spell with the pre-heater plugs was adequate for a first time start. It seemed to help, also, to use the starter without opening the throttle at all. The engine would begin to fire after about three or four seconds running on the starter motor, and was then ready for full power almost immediately. There seemed none of the usual delay associated with a cold petrol engine, and when driving off one notices the lack of water vapour from the exhaust.

On switching off, the key is just turned to the off position, locking the steering, and the engine stops with a slight convulsion as it comes to rest against the heavy compression.

One’s neighbours will soon be aware that one is running a diesel car, and they will hear every departure since the engine is very noisy to anyone outside, especially when it is cold and has not had time for the clearances to reduce with metal expansion. Inside the car, the noise level is extremely well suppressed and is certainly not objectionable. It is a little more noisy than the equivalent Citroen petrol car, but the difference is not very great, and is certainly not sufficient for an unknowledgeable passenger to notice. any difference. When passing between buildings, especially with a window open, the clatter echoed, back reminds one that the quietness inside is owed to excellent insulation of the bulkhead, and that for outside observers it is very noisy indeed.

Ahead of its competitors in many respects, this Citroen diesel is exceptionally smooth; it pulls strongly over a reasonably wide rev range, and there is no snatch or abrupt loss of power when it is taken up to the governed rev limit at 5,000 rpm in the indirect gears. On motorways the Citroen diesel proved well able to sustain the sort of 80-85 mph which is the norm for today’s business car traffic, and its ultimate maximum speed on the level of 89 mph can be exceeded downhill without over-revving since the governor allows a 5,000 rpm maximum engine speed.

Above: The engine itself is very different in appearance from that of the petrol CX and has different air intake arrangements, but otherwise under the bonnet is the same crowded but surprisingly accessible scene

Right: Only an extra "D" on the name plate instantly tells this is a diesel car, so prominent notices on and above the filler flap are necessary

Fuel consumption

Whoever buys a diesel car will do so primarily for its potential economy, and they will certainly not be disappointed. The 2200D returned an overall fuel consumption of 31.8 mpg for the full test, which is very creditable for a car of this size, including a lot of town work plus fast cruising on motorways. Several intermediate checks, including the one which covered performance testing at MIRA, returned over 33 mpg.

Because of the limited performance available we suspect that the normal consumption obtained by owners will be closer to our hard driving test figures than is usually the case. One should therefore regard 35 mpg as a normal target consumption. Derv in Britain currently costs about 2-3p per gallon less than petrol, but its relationship can be, and indeed is, altered by the Government’s fuel tax structure with regularity and without apparent rhyme or reason. Comparative overall consumption for the 2200 petrol was 23.5 mpg.

The same fuel tank is fitted, with a capacity of 15 gallons, so the 2200D has a phenomenal range. A full tank would take the car easily from London to Glasgow (420 miles). A fuel warning light is fitted among the row of tell-tales, and of course it is important not to run out because of potential difficulty in priming the injectors. No drop in oil level was noticed during the test. Engine oil must be of special grade for diesel engines; the level can be checked from inside the car using the pneumatic test button to the right of the facia.

Handling, ride and steering

Inevitably we have concentrated in this test on the differences due to the engine, since the rest of the car is very much the same as for the CX2000, as far as equipment is concerned. The 2200D must set some sort of new record in having nearly 70 per cent of the total weight on the front wheels, yet there is no direct awareness of this for the driver. The Varipower steering gives ample assistance to take the hard work out of pulling the nose of the car through corners, and the Michelin XVS tyres give such good grip that there is no tendency to slide straight on when cornering, even when braking. The exception is when driving on snow, when the nose-heavy handling calls for some caution.

Steering effort remains largely consistent, since the assistance given reduces as speed goes up. It is extremely accurate, coupled with the prominent directional stability resulting from such forward weight distribution, and the result is that the car is easy to hold straight at speed even in strong cross winds. With such sensitive steering, any slight movement off line tends to be noticed and it is best to avoid the temptation to do too much correction, or a weaving motion can result.

At low speeds the steering becomes noticeably heavier even with this varying rate of assistance, but still little effort is needed for acute changes of lock when parking. What one is having to overcome is not so much the resistance of the wheels, as the strong self-centring action 'of the steering. If the wheel is released, it spins rapidly back to the central position, and this happens even with the car at rest and the engine switched off.

Ride comfort afforded by the oleo-pneumatic suspension has been a Citroen legend for years and is equally impressive on the CX diesel. It is self-levelling to compensate for load and absorbs undulations magnificently. Sharp bumps or potholes produce a slight jolt and thump, but the suspension is generally above criticism and is an outstanding feature of this most comfortable car. A lever between the seats allows the ride height to be altered, chiefly to give extra ground clearance when needed for rough ground.

Upper part of facia panel is moulded in polyurethane, with the separate instruments and control panel mounted on it. Fingertip controls on the flying saucer-shaped panel are for indicators, horn, windscreen wipers/washers, and hazard warning on the left-hand extension and headlamps, flasher, dipswitch and panel rheostat on the right-hand one. Instruments are (from left to right) clock, speedometer, total and trip mileage recorders, pre-heater telltale, battery condition and fuel tank contents gauges, and there is a comprehensive row of warning lamps set above the instruments. On the right of the cubby hole alongside the steering column is a check gauge for engine oil level. The centre console houses a fresh air grille, the radio, directional fresh air vents, ashtray, cigarette lighter and controls for electric window lifts, heated rear window, and interior lamp. The heater controls are fore and aft slide levers set alongside the handbrake (behind the gearlever).

Brakes `

Ventilated disc brakes are fitted all round, and there is a pressure limiting valve in the line to the rear brakes. There is very strong servo assistance, such that only 40 lb load on the pedal, which is little more than is needed to work the clutch, gave 75 per cent efficiency. When first tested, on wet roads, this proved almost the maximum obtainable before the car began to skid. On dry roads, a 95 per cent stop is obtainable. Fade tests at three-quarters of maximum speed (68 mph) produced consistent, unaffected results.

A sturdy pull-up handbrake to the left of the driving seats (sic) holds the car securely and coped easily with the 1-in-3 test hill. Surprisingly, in view of the limited power and fairly high bottom gear, the car proved able to restart on this very testing gradient.

Comfort, fittings and equipment

Comments in our recent Citroen Safari Long Term Report need to be repeated in respect of the 2200D, concerning the unsuitability of the car for cold weather. The door locks are so prone to freeze up that it proved almost essential to leave the car unlocked at night, and the output of the heater is slow to build up and is inadequate for a frosty morning. Best delivery is from the central vents on the console, though most people prefer to have the warm air blowing directly on to their feet.

In other respects, the Citroen is a generously equipped, well-appointed and very comfortable car. There is a lockable drop-down glove box beneath the facia in front of the passenger, plus an open pigeon hole to the right of the steering column. All instruments and switches are neatly grouped in and around the broad hooded nascelle (sic), and the single spoke steering wheel (a Citroen tradition dating back to the original DS of 1955) gives an unobstructive (sic) view of the instruments.

The speedometer is digital, its figures being enlarged by a lens in the face of the instrument. A thumb wheel protruding beneath the finger-tip switch block on the right controls its illumination, which is independent of the side lamps. No rev counter is fitted, and the space normally occupied by this on petrol models houses the pre-heater telltale. The background features Citroen’s chevron trademark, and it seems rather pointless for this to be illuminated as well. A clock with second hand is fitted to the left of the speedometer, and a fuel gauge and battery capacity indicator are in the matching square on the right.

The single wiper blade, centrally mounted, clears a large area of the screen, and its switch control is so conveniently placed for trigger operation by the driver’s left hand on the wheel that the lack of any intermittent action or linked wash/wipe system is not a nuisance.

The seats are extremely comfortable, well-shaped, and have a measure of vertical adjustment as well as a lever to provide notched settings of the backrest. The front windows are electrically operated by a switch either side of the gear lever. Matching switches farther back control the heated rear window and interior lamp, which is adequately bright for map-reading at night.

Wind noise level is excellently low, so is the amount of road noise from the wheels on coarse surfaces. We do not consider these assessments to be influenced in relation to the rather higher than usual degree of engine noise.

Distinctive and aerodynamically efficient shape has marked the bigger Citroens for over 20 years. The streamlining is proportionately more advantageous with 66 bhp of diesel instead of 112 bhp of the outwardly identical petrol 2200
Unusual and futuristic style extends to the interior, where seats front and rear provide great comfort. Matching of moulded door handles with one piece door mouldings is not the neatest feature. Windows on this version are electrically operated at front, manual at the rear; absence of winders on front doors provides extra pocket space

Where it fits in

In all important respects, the equipment and furnishing of the diesel are the same as for the CX2400 Super; the CX2200 petrol is no longer listed. Exceptions are deletion of the rev counter and (obviously) the choke with its related warning light, and automatic (C-matic) transmission is not available. It is priced between the Super and Pallas versions of the 2400

Boot is deeper than CX’s exterior appearance might suggest, and the sill is down at the bumper line making loading of heavy objects easy. Floor is flat and unimpeded by spare wheel, which lives under the bonnet

Conclusion

As well as producing a major saving on fuel bills, one would reasonably expect a much longer life without overhauls to be provided by the engine. Because the equivalent petrol version is a rather lusty and not particularly refined unit, the penalty of the diesel in terms of extra noise and reduced power is not as marked as it might be, and the whole package is a satisfyingly efficient and still impressively pleasing car. We feel it right to end this test by emphasizing how impressed we are with the Citroen Diesel, and there is perhaps no better way to do this than to declare our intention to take one on to our staff fleet for long-term assessment.

MANUFACTURER:
SA Andre Citroen
quai Andre Citroen 133
Paris XV, France

UK CONCESSIONAIRES:
Citroen Cars Ltd
Mill Street
Slough, Berkshire

PRICES:
Basic £4,0l6.00
Special Car Tax £334.67
VAT £348.05
Total (in GB) £4,698.72

Seat Belts, inertia reel standard
Licence £40.00
Delivery charge (London) £27.00
Number plates £5.50
Total on the Road
(exc insurance) £4,771.22
Insurance Group 6

EXTRAS (inc VAT)
Motorola radio* £42.75
*Fitted to test car
TOTAL AS TESTED ON THE ROAD £4,813.97

Specification

ENGINE: Front, front drive
Cylinders 4 in line, transverse
Main bearings 5
Cooling Water
Fan Electric
Bore, mm (in) 90 (3.54)
Stroke, mm (in) 85.5 (3.37)
Capacity, c.c. (in) 2,175 (132.7)
Valve gear ohv
Camshaft drive Gears
Compression ratio 22.25-to-1
Fuel Derv
Carburation Bosch Rotary or Roto Diesel injection
Max power 66 bhp (DIN) at 4,500 rpm
Max torque 92.6lb. ft. at 2,750 rpm
TRANSMISSION:
Type Four-speed, all synchromesh
Clutch Single plate, diaphragm
Gear Ratio mph/1000 rpm
Top 0.8 19.3
3rd 1.13 13.6
2nd 1.83 8.4
1st 3.17 4.8
Final drive gear Helical spur
Ratio 4.77-to-1
SUSPENSION
Front-location Independent, upper and lower transverse arms
- springs/dampers
Hydropneumatic units
- anti-roll bar
Yes
Rear-location Independent, trailing arms
- springs/dampers Hydropneumatic units
- anti-roll bar Yes
STEERING
Type Rack and pinion
Power assistance Varipower standard
Wheel diameter 14 in
BRAKES
Front 10.2 in dia disc
Rear 8.6 in dia disc
Servo Hydraulic
WHEELS
Type Pressed steel
Rim width 5 1/2J
Tyres - make Michelin
- type XVS radial
- size 185 (front) 175 (rear) 14 in
EQUIPMENT
Battery 12 volt 88Ah
Alternator 72 amp
Headlamps 4 lamp halogen 90/ 190 watt (total)
Reversing lamp Standard
Hazard warning Standard
Electric fuses 10
Screen wipers 2-speed
Screen washer Electric
Interior heater Water valve
Interior trim Jersey seats, PVC headlining
Floor covering Carpet
Jack Screw pillar
Jacking points 2 each side under sills
Windscreen Laminated
Underbody protection Tectyl
MAINTENANCE
Fuel tank 15 Imp galls (68 litres)
Cooling system 12.5 pints (inc heater)
Engine sump 7.7 pints SAE
Gearbox and final drive 2.8 pints SAE
Grease No points
Valve clearance Inlet 0.006in Exhaust 0.008in. (cold)
Contact breaker None
Ignition timing N/A
Spark plug N/A
Tyre pressures F29; R 29 psi (normal driving)
Max payload 1,034lb (470kg)

Maximum Speeds

Gear mph kph rpm
Top (mean) 89 143 4,600
Top (best) 90 145 4,650
3rd 66 106 4,850
2nd 42 68 5,000
1st 24 39 5,000

Acceleration

True mph
Time (sec)
Speedo mph
30
5.9
32
40
9.3
43
50
14.6
53
60
20.8
63
70
30.8
74
80
50.8
84
90
-
96
Standing 1/4 mile: 21.9 sec 61 mph
Standing kilometre: 40.7 sec 74 mph
mph
Top
3rd
2nd
10-30
-
9.4
5.6
20-40
14.2
9.2
9.2
30-50
14.7
9.6
-
40-60
22.4
11.1
-
50-70
29.3
-
-
60-80
30.1
-
-

Consumption

Fuel
Overall mpg: 31.8 (8.9 litres/100km)
Calculated (DIN) mpg; 33.3 (8.5 litres/100km)
Constant speed
mph mpg
30 60.3
40 55.3
50 49.6
60 41.8
70 36.6
80 30.4
Autocar formula
Hard driving, difficult conditions 28,6 mpg
Average driving, average conditions 35.0 mpg
Gentle driving, easy conditions 41.3 mpg
Grade of fuel: Derv
Mileage recorder: 2 per cent
over reading
Oil
Consumption (SAE 30/HD3C) negligible

Brakes

Fade (from 68 mph in neutral)
Pedal load for 0.5g stops in lb

start/end
start/end
1 30/35 6 35
2 30/35 7 35
3 35 8 35
4 35 9 30
5 35 10 30
Response (from 30 mph in neutral)
Load g Distance
20lb 0.40 75ft
40lb 0.75 40ft
50lb 0.85 35ft
60lb 0.95 32ft
Handbrake 0.35 86ft
Max gradient 1 in 3

Clutch

Pedal 40lb and 5 1/2 in

Test conditions

Wind 8-10 mph
Temperature: deg C (38 deg F)
Barometer: 28.7in Hg
Humidity: 100 per cent
Surface wet asphalt and concrete (dry for final brake test);
Test distance 781 miles

Figures taken at 5,400 miles by our own staff at the Motor Industry Research Association proving ground at Nuneaton

Regular service

Interval


Change
3,000
6,000
12.000
Engine oil
Yes
Yes
Yes
Oil filter
No
Yes
Yes
Gearbox oil
No
No
Yes
Spark plugs
None
None
None
Air cleaner
No
Clean
No
C/breaker
None
None
None
Total cost
£2.75
£12.92
£25.85
Assuming labour at £5.50 per hour

Parts cost

(including VAT)
Brake pads (2 wheels) - front £15.65
Brake pads (2 wheels) - rear £10.69
Silencer(s) £23.94/18.96
Tyre-each (typical advertised) £37.64
Windscreen £82.08
Headlamp unit £50.78
Front wing £35.34
Rear bumper £84.11
Warranty Period 12 months unlimited mileage

Weight

Kerb 28.0cwt/3,140lb/1,426kg
(Distribution F/R) 67.9/32.1
As tested 31.57cwt/3,536|b/1,605kg
Boot capacity 16.8cu ft
Turning circles Between kerbs L, 35ft 9in; R, 35ft 4in

Between walls L, 38ft 8in: R, 38ft 6in
Turns, lock to lock 2.5

Test Scorecard

(Average of scoring by Autocar Road Test team)
Ratings
6
Excellent
5
Good
4
Better than average
3
Worse than average
2
Poor
1
Bad
PERFORMANCE 3.35
STEERING AND HANDLING 4.25
BRAKES 4.40
COMFORT IN FRONT 3.75
COMFORT IN BACK 4.57
DRIVER'S AIDS 4.00
(instruments, lights, wipers, visibility, etc.)
CONTROLS 3.63
NOISE 4.17
STOWAGE 3.67
ROUTINE SERVICE 3.56
(under-bonnet access, dipstick, etc.)
EASE OF DRIVING 3.72
OVERALL RATING 3.93

Comparisons

Car
Price
(£)
max
mph
0-60
(sec)
overall
mpg
capacity
(c.c.)
power
(bhp)
wheelbase
(in.)
length
(in.)
width
(in.)
kerb
weight
(lb)
fuel
(gal)
tyre size
Citroen CX2200D 4,699
89
20.8
31.8
2,175
66
112
181
68
3,140
15.0
185/175HR14
Citroen CX2000 Super 3,956
110
12.2
23.2
1,985
102
112
181
68
2,788
15.0
185/175HR14
Mercedes-Benz 300D (A) 7,600
90
20.8
25.7
3,005
80
110
186
70.3
3,290
17.2
175SR14
Opel Rekord 2100D (A) 3,988
81
27.4
27.0
2,068
60
105
180
67.8
2,773
15.4
175SR14
Peugeot 504D 4,042
84
21.7
31.1
1,948
56
108
177
66.5
2,607
12.3
165SR14



© 1977 Autocar/2011 CitroŽnŽt