The affordable 24-valve
The November 1989 debut of the (deep breath) Vauxhall Carlton GSi 3000 24v was unmarked by a formal British launch, or the hypocritical welter of 170 mph words that accompanied the twin turbo Lotus Carlton. Yet the GSi flagship of the Carlton mass production line is a more significant sports saloon than the Lotus variant. When this 24v arrived in Britain it established a sub-category for affordable six-cylinder performance.
Some 2500 24v Carltons have been sold in our country since then. Only now are the opposition beginning to realise what a profitable, and enjoyable, niche GM have prised open. At first comparisons were drawn with the BMW 535i Sport, Autocar & Motor flagging the results of a confrontation test, “what’s better than a BMW 535i and costs £7000 less?” Today the £26,975 tag upon the Vauxhall includes a standard catalytic convertor and much sundry showroom equipment (electric operation of sunroof, controversial LCD display dashboard, electronic ABS braking and so on) which leaves it £5675 less than said BMW. Those of you with technical appreciation will know that a 535i Sport is powered by one of Munich’s traditional 12-valve 3.5 litres, so that a true technical equivalent is the £45,750 M5. The M5 does have a 24v engine, albeit one of considerably more power (over 300 bhp) than the general consensus of 200 to 220 bhp allows UK motorists.
The sheer cost and rarity of the BMW M5 left Vauxhall the affordable market for 24v “executive express” from late 1989 to the early Summer of 1990, although Jaguar could be said to be opposition with the 3.6 and latterly 4.0 24v sixes assessed by Motor Sport last winter. Now the 24v six-cylinder saloon market has been further enlarged to the point of offering a choice of Cosworth-concocted Ford Scorpio (automatic only, £27,383), Peugeot SVE 605 24v (£27,250, front-drive only), and the same V6 engine is in the Citroën XM (£27, 495).
Having driven all the cars nominated, we thought it time to look at the Vauxhall again and see if anyone had come up with a better recipe at the price? First impressions of the silver test car were not overly favourable. It is a brash vehicle, laden with aerodynamic appendages and a two-deck badge that proclaims the company’s lack of confidence in its identity by shouting “CARLTON GSi 3000” in capital letters, supported by a chrome and red “24v” plaque. The same lack of confidence is seen from the beautifully shaped four-spoke leather rim wheel, which repeats the model identity message.
Then you blink the illuminated dashboard display to life, via the ignition key. It goes through a yellow and black numeric sequence that includes flashing up a 288 mph reading for the digital speedometer. “Flashy” is the immediate reaction, particularly when one acquaintance asked cheekily, “where’s the slot for the coin, so the games machine can begin?”
Less garish and more useful were the six computerised readouts provided to cover items such as fuel consumption and average speed. The computer was up to 2 mpg optimistic, but this substantial (15.4 ft long) Vauxhall managed several journeys with averages beyond 60 mph and 21 mpg in sporting comfort. Contributing to the sense of security are sports front seats and a restful selection of grey fabrics and black plastics. GM did allow themselves a single red and blue stripe upon the seats and trim panels. The overall effect is of 85 per cent BMW quality, without the tomb-like sobriety.
We were impressed by the deadlock door and boot locks, part of a Vauxhall drive to meet the scandalously high automotive crime; the contrast with our staff Sierra Cosworth was painfully marked. Some of the GM interior touches were not so deft, quality apparently presented where the customer notices. Elsewhere the major effort is lacking. Items like cabin door handles with variable plastic finishes and occasional blemishes, on to less inspired fit and finish that is visible to the questing eye.
The motor hums to life in true six cylinder, Bosch management style. We think GM did not receive quite the same flawless electronic standards as BMW or Porsche, or the company budget did not allow the necessary man hours to do the calibration 100 per cent correctly. There were occasional surges in the drive line and the motor did not always pick up with the precision expected in 1991.
Performance figures were on a par with what was expected, but the feeling that “carburation” versus electronic mapping had not been conscientiously completed. Perhaps they would be better off with Lotus engineering and Delco hardware?
The sound of this six-cylinder was traditionally suave until 3000 rpm, then it became a little more lively to 4000 rpm. There is a definite hiccup at this point as the “dual ram” (a single butterfly valve fitted between two plenum chambers) acts to optimise intake manifold flow patterns beyond 4000 rpm. By 3600 rpm it had spoken of maximum torque achieved and an urgent need to conquer the 6500 rpm electronic limiter.
It is far from the smoothest six we have driven, but no disgrace either, allowing the driver satisfying deployment of its horsepower. In commercial terms we would describe it as closest to the Cosworth version of the Ford 2.9-litre V6, but that has been saddled with an automatic in displaying the worth of its 195 bhp at 5750 rpm and 202 lb ft of torque by 4500 rpm. This Carlton is a mass-produced four seater that is veering toward genuine 150 mph capability. By the time you amass 145 mph around Millbrook bowl, it is fair to say that 2-3 ultimate mph are being lost over a lap, so the silver Vauxhall did come awfully close to the 150 mph barrier. That it does so on an official 16 bhp less than the 4×4 Sierra RS Cosworth tells us that rear-wheel-drive and conscientious application of aerodynamics (whatever our aesthetic reservations) are still potent forces in the provision of performance saloons.
Of more relevance to potential owner drivers will be the immense motorway cruising capabilities. This Carlton in German Omega guise is able to sustain 100 to 125 mph all day (in round figures, 4000 to 5000 rpm in fifth), when radio listening and normal conversations can continue with commendably low escalation in wind or tyre noise. At Britain’s 70 mph limit and just 2900 rpm in fifth, the Carlton ambles along quietly, supping approximately 31 mpg.
The acceleration is not quite in the RS Ford bracket, but it is outstanding for a current 3-litre saloon. Vauxhall 24v drivers are unlikely to feel they have been short changed. The only obstruction to straightline pleasure is the vague gearbox gate the light, elongated, change occasionally drifting from a third gear slot to fifth.
Initially the handling seems a bit sloppy with the contradiction that the low-speed ride is obviously over-damped, but tackle a nasty minor road assortment of adverse cambers and bumps fit to throw the old front-drive Escort into spasms and the 24v Carlton sweeps imperiously through, the occupants unruffled and the driver enjoying a constant feedback of information from the wheel rim and supportive seats. As with many cars developed by German engineers, the harder you drive, the better the ride.
Also well above average is the grip provided by Uniroyal 205 section rubber and rear traction during a standing start. The Carlton does not quite cut it versus the original Mercedes-Benz multi-link system, or the current BMW independent rear end, but GM have created a distinctly worthwhile argument for the merits of rear-drive in a sports saloon.
We feel that nobody does a better job of the sporting six-cylinder saloon at this cost than Vauxhall, certainly not amongst the mass production ranks. Its combination of rear-drive handling finesse, excellent pace and routine service durability/economy is not matched, as yet.
If cost is no object, we believe the BMW M5 is one of the finest sports saloons ever made: charismatic, fearfully fast and hand assembled by a labour force that cares to a degree that cannot be duplicated in the sub £30,000 classes.
Ford could compete with Vauxhall in two ways: promote the virtues of a £25,500 Jaguar 4.0 XJ6 saloon with a £2000 sports suspension pack, or make the recently announced Cosworth Scorpio a more clearly defined sports saloon, including manual transmission and a clear identity. Or both.
Meanwhile, Vauxhall show that their recent public image as providers of better products at competitive cost is based on genuinely impressive motor cars. This Carlton is far from perfect, but is less flawed where it matters than its opponents. — JW
Key Features: Vauxhall 3.0-litre Carlton GSi 24v
Tax-inclusive price: £26,975.
Body: Steel, 4-door saloon, with aerodynamic body equipment, front, rear and sides, plus protective centre line moulding.
Drag factor: 0.30 cd.
Engine: Inline 6-cyl, 2969cc (95 x 69.8nun). DOHC, 24-valve alloy cylinder head, iron cylinder block; 10:1 Cr. Bosch M1.5 electronic fuel injection and ignition management +Lambda probe for standard catalyst. Power outputs: 204 bhp (@ 6000 rpm; 199 lb ft @ 4600 rpm.
Transmission: Longitudinal engine drives rear wheels via single plate clutch and two mass flywheel: 5-speed gearbox. Ratios: First, 3.807; Second, 2.106; Third, 1.335; Fourth, 1:00; Fifth, 0.814 (24.4 mph per 1000 rpm). Final drive, 3.70.
Running gear: Suspension Sport, front MacPherson gas pressurised strut settings with antiroll bar. Independent ACT multi-link rear suspension, two semi-trailing arms and one cross link connecting hub and suspension subframe via ball joint and damping bush. Gas telescopic dampers,double conical mini block progressive rate coil springs and separate anti-roll bar.
Steering: Recirculating ball, 15:1 ratio, 3.7 turns lock-to-lock.
Brakes: Ventilated 10.2 inch front discs; solid 10.6 inch disc rears; electronic ABS is standard.
Wheels & Tyres: Alloy 7 x 15 inch and 205/65 ZR Uniroyal 340/65 Rallye.
Vauxhall Carlton 3.0-litre GSi.24v
Millbrook Proving Ground test site, using Correvit electronic measuring gear.
Acceleration: 0-30 mph 2.8 seconds; 0-60 mph 7.4 seconds; 0-100 mph 29.0 seconds; Standing 0. 25 mile/400 metres: 15.4s @ 89 mph; Flexibility 50 – 70 mph in fifth gear: 10.5 seconds
Maximum speed: 145.1 mph
Test distance: 450 miles. Overall test fuel consumption: 21.4 mpg. Government mpg figures: Urban, 19.8 mpg; 75 mph, 30.7 mpg; 56 mph 37.2 mpg.