AUTOCAR´S ROAD TEST:
The body shell of the Citroen CX GTi Turbo may be virtually the same as the CX designs of a decade ago, but impressive innovations adorn the 1985 model. Andrew Kirk reports; Andrew Yeadon provides the photography
Off and running: the visual transformation of the CX GTi into a Turbo version includes distinctive alloy wheels
The latest Citroen is the fastest CX ever made and a car which the company sees as a worthy successor to the legendary Citroen SM. The car is the CX GTi Turbo, based on the body shell which, as long ago as 1974, replaced the ageing DS. Ten years ago the current public awareness of drag coefficients did not exist but it is worth recalling that the DS had an impressivelv low coefficient of 0.37. With the CX GTi Turbo, that has been reduced to 0.36. The CX GTi Turbo does not look that different from the less powerful CX GTi and the changes made are of a restrained but sporty nature. Distinctive alloy wheels, with letter T cutouts, come equipped with the widest tyres ever fitted to a production Citroen: Michelin TRX 210/55 VR 390 low profile radials. The wide footprint tyres plus the equally large remotely operated door mirrors effectively raise the drag factor but a newly-designed rear spoiler has brought the figure back down to Cd 0.36. Discreet turbo badging on the front wings, T symbols, blacked out window trim and a distinctive twin exhaust tail pipe
CX GTi: new legend?
add to the visual transformation. The real changes are under bonnet and, in simple terms, involve the Citroen engineers bolting on a turbocharger. In reality, of course, this is not quite so straightforward a job. The same 2500cc engine of the GTi is used but in turbo guise it has the compression ratio reduced from 8.75:1 to 7.75:1 to help lower detonation. The crossflow combustion chambers are modified and the pistons feature flat crowns in an effort to reduce heat build up. Engine response is aided with the addition of a modified inlet manifold which is reduced in size. The turbo boosts to a maximum of 8 psi and is largely responsible for upping the power output from the 138 bhp of the GTi to 168 bhp at 5000 rpm for the GTi Turbo.
Impressive: acceleration without a jerky transition boost. Climbing: handbrake proves adequate on the 1 in 3 test slope
TURBOS are renowned for their ability to increase power output with useful benefits in improved torque, and this latter aspect is fully exploited. A Garrett AiResearch T3 unit is fitted - the ideal size for the engine capacity - and the installation is tailored to develop peak torque of 217 lb ft at only 3250 rpm. Rather than concentrate on out-and-out acceleration Citroen has chosen to improve pick-up and, even at 1,500 rpm, there is a very usable 144 lb ft torque. As a result, there is ample power for quick overtaking manoeuvres and enough engine flexibility to avoid having to snatch the gears to get the revs up.
With acceleration from rest, there is plenty of wheelspin and the car launches well, but the impression of speed is masked by the high level of interior refinement.
From start, 60 mph appears in only 8.6 seconds; an excellent figure considering that the GTi Turbo tips the scales at over 3,000 lb. The car gets to 100 mph in 24.3 seconds and with great ease. The engine is quite rough at low revs but smooths out over 2,000 rpm. Upwards of this figure a careful eye must be kept on the revcounter, especially in first and second gears, to avoid hitting the engine ignition cutout at 6.000 rpm as the boost comes in. The transition from part to full throttle as boost comes in gives only a slight lag with smooth take-up and an impressive power surge. Annoying, from a test point of view, is that two gear changes are necessary to reach 60 mph. Second gear runs up to 55 mph at 6,000 rpm and the second to third change, which does not like to be hurried, means that it is a matter of polished technique to achieve a 0-60 mph figure nearer the claimed time of 8 seconds.
Acceleration in both fourth and fifth gears shows the impressive torque to the full. The 30 to 50 mph time in fourth of 6.7 seconds is in fact slightly slower than the 6.5 seconds it takes from 60 to 80 mph when the engine is boosting more efficiently.
Maximum speed is reached in fifth gear and clocked a rather disappointing 126 mph compared to the Citroen claim of 136 mph. Our car had only 1,700 miles on the clock at the time of testing but even so we would hardly have expected such a large difference between the two figures. The car did produce a downwind burst to 128 mph but would go no faster. The overall maximum corresponds to 5 000 rpm, spot on peak power from the 25.19 mph/1,000 rpm top gear. Theoretically the car is capable of acceleration above peak power provided the power curve is right and we suspect that on a long straight run the claimed. 136 mph may be possible, corresponding to only a 400 rpm rise under present gearing.
Whether the car is driven hard or not, the variation in fuel consumption is only marginal. Our car returned 20.1 mpg overall - slightly better than the claimed 20.1 mpg for the urban cycle, and the figures varied only between 18.3 and 21.4 mpg throughout the 800 mile test period. The Turbo's thirst is matched by a tank which even at 15 gallons, needs more frequent filling than one might first imagine. We managed a best of 237 miles and a worst figure of 209 miles between fills. Fortunately, the car brims quickly and has a wide filler neck.
Even after a seven day familiarisation period we would want more time behind the wheel to get to grips with Citroen's self-centring power-assisted steering. Though the selfcentring effect is a great help in keeping the car pointing in the right direction at speed - it ploughs on arrow straight whatever the conditions or speed - it can become a hindrance in parking.
Sometimes situations arise where you would prefer to have the wheels pointing in a certain direction when stationary, but this is not possible as they automatically revert to straight ahead as soon as you let go of the wheel, whether the engine is running or not. The steering also has a certain amount of dead feel if the wheel is turned from side to side and it is difficult to tell whether the wheels are moving or not due to that lack of feel. On a happier note, with only 2.5 turns from lock to lock tight manoeuvres are easily managed. If the steering is open to criticism, the suspension is less so. The familiar CX hydropneumatic system is retained but is suitably uprated in Turbo guise to handle the increase in power. Damping rates are increased and thicker diameter front and rear anti roll bars substituted. The system provides the familiar Citroen soft ride combined with superb bump absorption. The ride height is constantlv adjusted via the built-in selflevelling and, for such a big car, the CX handles very well indeed. Understeer is the predominant factor when cornering hard and the rear can be provoked to break away - but only in a very gentle way - if vou shut the throttle. The car does not react violently and it is easy enough to regain control.
Gears: two changes for 60 mph
The suspension does most of the work to keep level and slight steering action is all that is required to get the tail back on line. It does not feel as if there is rolling to any major extend when on the limit and the suspension passes through a good feel to the driver. Even when the inside rear wheel lifts, which it does without too much provocation as a result of the stiffening, the car remains steady. As with the steering the brakes take some time to get used to, though they are much easier to cope with. In typically Citroen fashion the pedal travels less than an inch and the force required is a bare minimum, a point backed by the fact that only a 43 lb load is necessary to achieve deceleration. Though they feel over secure at low speed, you appreciate their efficiency at high speed; it is here that the brakes feel well matched to the power input. Their performance is impressive and throughout the tests pedal pressure started 20-24 lb and never increased above 28-36 lb. Clearly the wheel discs - with ventilation up-front - are more than adequate. The handbrake also proved adequate on the 1 in 3 test whether facing up or down.
BEHIND THE WHEEL
THE INSTRUMENT cowl is familiar to CX owners, but the gauges are totally new. Conventional pointer gauges are fitted in a smart and compact group and the black faced instruments, with white numbers and bright orange pointers, look both purposeful and neat. The larger speedometer and tachometer are flanked to the left by smaller oil temperature and water temperature gauges and, to the right, by fuel and oil pressure gauges; the latter also doubles as a dipstick level indicator. Set into the tachometer is the turbo boost gauge and, in the speedometer, a milometer and trip. Citroen have retained the familiar rocker switch arrangement for indicators and main beam, plus the fingertip controls for horn and headlamp flash.
These allow the driver to keep both hands on the wheel in the ten to two driving position. Switches for lights and wipers hang beneath these and are fiddly at first, but easy enough once familiarised. The pedal arrangement is comfortable and the pedals are well spaced for easy operation. The clutch pedal has 5in travel and is pleasantly light at only 28 lb. A 15 in steering wheel is fitted, quite a smart leather-bound design with the word turbo embossed in the centre section. However, most drivers will find the wheel too large in diameter as a splayed legs driving style has to be adopted. Steering effort is sufficiently light that a smaller wheel would not affect it detrimentally. The problem of limited driver legroom could also be alleviated to a large degree if the front section of the seat could be lowered. The base can be dropped at the rear to give more headroom and rake is adjustable too, but not the front. Another solution would be to make the steering column adjustable. We quite liked the feel of the seats on first acquaintance but changed our minds after six hundred test miles behind the wheel. You sit in, rather than on them and, with little air circulation to the body, the position gets very hot and stuffy the longer you drive. The backrest does not give very good support either. In what feels like the optimum setting your back is pushed forward at the base of the spine. Consequently, the base feels too soft and the backrest too hard.
In view: totally new gauges include the turbo boost register set into the tachometer
THE BIG Citroen really comes into its own at high speed where it will cruise effortlessly for hours on end. You only need touch the throttie to send it surging on and the response is always impressive, whatever the speed. There is plenty of tyre roar from the fat footprint Michelins and a deep roar resonates round the interior compartment at high speed. The front windows whistie a bit at anything over 70 mph, as if they are not properly shut, and often the car was much quieter if they were re-closed. Starting from cold is trouble free. The starter motor is quite loud but always whirs the engine into life first time and the automatic choke works well during the short initial warm up period.
THE CX dates back to 1974. It has seen little change in body design and construction since then and has the usual in-built safety features designed to protect the occupants in an accident. The inclusion of a rigid passenger compartment with extra support to the seat belts means that they operate properly in emergencies. The interior is designed for impact absorption and to quote from Citroen information "the material responds to the fragility of human organs" though fortunately we never had the misfortune to put this claim to the test. The CX feels a big safe car with its large crumple zones and we liked the real metal bumpers, which are such a rare feature these days, although they could be a source of injury to pedestrians as they certainly "give" less than conventional plastic bumpers. Rear seat belts are only an accessory at the moment but Citroen are taking a step in the right direction by offering them as an option for 1985. Safety accessories include a child harness, carrycot restraint, safety seat for use both in and out of the car and a raised cushion for use with an existing three point adult belt which is suitable for children from about three years old upwards. Since the model is of continental Europe origin, it is taken for granted that all aspects of its design meet international safety regulations instituted to date.
Roomy: front seat passengers can strecth their legs
LIVING WITH THE
THERE APPEARS to be a fair amount of wasted space inside the CX which is best illustrated by the large concave shaped dashboard. This is beneficial in giving a roomy feel to front seat passengers, but it could have provided additional cubby space. A locking glove compartment of reasonable size sits below this, and small but deep door pockets are included, suitable for rolled up maps and the like. The only other storage area is a narrow slot in the dashboard to the right of the wheel. This is also very deep and means that coins and other small items are difficult to retrieve. Fresh air ventilation is adequate but the inclusion of a predominantly black and grey interior has resulted in a stuffy cockpit in warm weather if the fan is not kept running. Fortunately the fan is quiet enough on the first setting so as not to cause passenger discomfort. Two small eyeball type vents on either side of the dashboard and two rectangular vents to the centre are fitted. The heater output is enough to cope with severe misting and is aided in this by a quick acting heated rear window, operated by a roof mounted switch. Heating and ventilation controls are housed in a centre console between the front seats and consist of three slide controls. These are easy to operate though you have to glance down for a split second to make sure the right lever has been selected. Forward visibility is very good, thanks to the large screen and sloping bonnet, though steeply angled windscreen posts do create large blind spots. One piece side windows, with power assistance controlled by centrally mounted switches, are usefully large and the only real problem areais when you lookthrough the rear view mirror. Though the screen is big it is also steeply raked and the addition of the large rear spoiler reduces rearward vision to a slit. This is adequate for most driving situations but not quite so good when parking or reversing - though the large door mirrors help matters considerably. Interior space is ample for four average-sized adults, but the long thin cigar shape has meant that sacrifices have been made in this area compared to its rivals. Six footers will experience difficulties with rear seat headroom, but cutouts in the front seats are provided to give improved legroom. Rear passengers also benefit from a pull down centre armrest, sun visors for each side window and twin pull up perforated blinds fixed to the parcel shelf to cut down glare from the rear screen. You could be forgiven for thinking that the GTi Turbo is a hatchback with its similarities in styling but this is not the case, The car has a conventional boot of average proportions, but one which could be easily increased if Citroen were to fit a folding rear passenger seat. The sill is usefully low and the boot lid raises high to further aid loading.
CITROEN STARTS with the 2500cc engine block of the CX GTi. It is fitted with a forged steel crankshaft, wet cast iron liners, steel connecting rods, light alloy flat topped pistons and alloy cross flow cylinder head equipped with two valves per cylinder. The camshaft is mounted in the block and operates the rockers via conventional tappets and push rods. To this layout is matched a Garrett AiResearch T3 turbocharger, chosen as the optimum size for the engine capacity and this delivers the suitably charged air of up to 8psi boost via the specially cast inlet manifold into the combustion chambers. These feature a low 7.75: 1 compression ratio to further reduce detonation problems. Fuel supply is by electronic injection using the Bosch L-Jetronic system which includes an engine speed limiter. An "over-pressure" sensor on the turbo also activates fuel cut-off if necessarv. Solid state integrated electronic ignition - similar to that used in the CX GTi incorporating a knock sensor, alters the ignition timing at the onset of detonation. This has no moving parts so theoretically no wear either. By current state-of-the-art turbo installations the big Citroen has a straightforward, but perhaps primitive, turbo system since it is devoid of the more favoured intercooling. In simple terms the intercooler is a small radiator that cools the air from the turbo before it is delivered back into the engine. Such a cooling process increases the density of charged air which has the effect of producing more power. It has been omitted on the CX because of a lack of under bonnet space, because the existing ignition knock and retard facility do the job well enough and because Citroen see the existing power output as adequate.
WE WERE impressed with the effortless performanee and high levels of reflnement but similarly unimpressed with the only average fuel consumption, limited range and unconventional steering. The brakes we came to like but we would have to live with the car for a much longer period to get to grips with the self-centring steering system. No doubt Citroen drivers will have little difficulty in adapting to the CX GTi Turbo but drivers of other makes will find the transition more of a problem. Overall, we felt that there were other cars that offered as much if not more in this particular market sector. The Renault 25 V6 Injection is the first car that springs to mind at only around £500 more. Performance is similar - torque not quite so good - and economy similar, but the Renault is more spacious more modern in interior layout and has better ergonomics. Another contender in the £13,000 region is the BMW 528i and, although the sheet metal is now perhaps a little dated. it is still good value for money. Besides the glorious performance from the 2.8-litre fuel injected straight six there is also classwinning fuel economy. In addition, it is a well accomphshed drivers' car, which is what this sector of the market is all about. For this reason we have given it our top vote. Though much more expensive at £17,013 we get the impression that buying an Audi 200 Turbo is also money well spent. Some would argue that the car is not so different from the equally excellent Audi 100 to warrant such expense , but a session behind the wheel is enough to convert most. Given the available space it can be wound up to 142mph, which is no mean feat considering the Audi is down on power compared to its rivals. If a booted car is preferred, then the choice is between the Audi and BMW, though the first has slightly more space at 20 cu.ft. Both better the Citroen's 17.9 cu.ft. Hatchback alternatives are the Rover and Renault but the two German cars get our overall vote as the most accomplished all rounders.
Engine: 2500 cc, but with reduced compression ratio, plus a T3 turbo
Acceleration from rest
Acceleration in each gear
Standing 1/4 mile : 16,7 secs 83mph
Standing km : 30,2 secs 106 mph
Reprinted partially from Autocar 24th October 1984