ROADTEST 

BMW 628 CSi  

Smaller-engined version of BMW’s slingshot 635 aimed more at the well-heeled executive than sporting enthusiast. But with less power, has this £16,000 quality coupe lost its appeal? 

(Motor, 27 December 1980. UK.) 

It has been over a year since BMW dropped its 3.3 litre-engined 633 CSi coupe from its UK model range leaving the larger-engined, more sporting and more expensive 635 CSi as the only remaining 6-series.

   With the recent introduction of the Mercedes Benz 280 SLC coupe to Britain, however, BMW decided it needed a more closely-matched contender in this lucrative section of the market – hence the arrival of the new 2.8 litre 628 CSi coupe which we test here.

   In Germany, the 628 has been available since the beginning of the year and like the UK version’s, its fuel-injected 2.8 litre six cylinder engine is derived from that of the 528i saloon. But the Continental car has a four-speed gearbox while the UK 628 has a five-speed overdrive unit.

   It would take a keen eye to spot the new car from its predecessor, the 633. As before, the 628 has a steel monocoque chassis, the floor pan of which is adapted from the 5-series saloon’s. The front suspension is by MacPherson struts and coil springs, with power-assisted ZF worm and roller steering, and at the rear there are the pair of familiar BMW semi-trailing arms, again with coil springs. The suspension itself can be uprated by fitting gas-filled shock absorbers, stiffer springs and thicker anti-roll bars which are available as no-cost option.

   Outwardly the 628 is distinguished from the more sporting 635 only by its lack of spoilers and wide-rimmed alloy wheels. Inside too, little has been changed though the leather upholstery fitted to the test car can be replaced with velour cloth at no extra cost, as too can the front seats, which can be interchanged with the more curvaceous Recaro seats normally fitted to the 635.

   Normal standards of value-for money do not pertain when you are considering cars in the 628’s price range. But the current strength of the pound has allowed BMW to price the new coupe more competitively in the UK as well as offer a number of no-cost options. At £16,635, the 628 is close to £1,000 cheaper than its main rival, the Mercedes 280 SLC (£17,600) which for Britain is only available in automatic form. Other rivals include the superb Jaguar XJS (£19,187); the Porsche 911 SC (£16,732) and its bigger stablemate, the 928 (£21,827); The Lotus Elite 2.2 (£16,433); and the Ferrari 308 GT4 (£17,534) which is soon to be replaced by the new Mondial. Cheaper rivals include the Opel Monza S (£12,808) which is now available with a 5-speed gearbox and the Lancia Gamma Coupé (£10,500).

   We still find it hard to understand why coupe versions sell for considerably more than their saloon counterparts and in this case the 628 is no less than £4,200 more expensive than the similar-engined, yet larger-bodied 728i which has the advantage of two extra doors and a more spacious interior. Nevertheless, the 628 fills an important gap in the BMW range. It is also an extremely refined, comfortable and superbly finished ‘quality’ coupe with excellent ride and handling qualities together with good fuel economy. Its outright performance for a car with sporting pretentions can only be judged as fair, with its shortage of low-speed torque being the main shortcoming. It also falls down on poor rear seat legroom and mediocre heating and ventilation.

   Similar to that of the 528i, the 2,788cc straight-six engine has an identical power output of 184 bhp (DIN) at 5,800 rpm with maximum torque of 177.2 lb ft (DIN) produced at 4,200 rpm.

   Not surprisingly, the 0-60 mph acceleration time of 8.3 sec was identical to that of the similar heavy 528i we last tested, with little to choose between the coupé’s 0 – 100 mph time of 23.6 sec and the saloon’s 23.9 sec. Although its acceleration may seem brisk, the BMW is outsprinted by all but one of our chosen rivals, which admittedly are either lighter or more powerful or both. Unfortunately we have not yet been able to test the Mercedes 280 SLC, but it should be considerably slower than the BMW, according to the manufacturer’s claims (0-60 mph in 11 sec).

   If the 628’s through-the-gears acceleration is to be judged as mediocre for its class, then its fourth and fifth gear pick-up can only be described as poor. In fourth, acceleration from 30 to 50 mph takes 9.8 sec while in fifth the same increment takes a yawning 13.9 sec. These figures confirm our testers’ subjective opinions that the BMW feels no fireball, certainly by £16,000 standards. While the engine pulls cleanly from very low revs, its poor torque below 3,500 rpm gives the car a sluggish feel and if brisk progress is to be maintained, then you must use the gear to keep the engine spinning above this level.

   We weren’t able to verify the car’s claimed maximum speed of 130 mph, but timed checks on MIRA’s banked circuit suggested that this figure was within the 628’s capabilities.

   As with all applications of the excellent Bosch L-Jetronic fuel-injection system, we have sampled, starting is instant and warm-up impressively hesitation-free. As yet the Bosch-BMW ‘Motronic’ engine management system where a micro-computer controls both ignition timing and fuel injection is not yet available on the 628.

   One of the areas the ‘Motronic” system is designed to improve is fuel economy, yet even without it most owners should be satisfied with the 628’s economy. We achieved 19.8 mpg (14.3 l/100 km) overall despite our usual hard driving, a figure which most drivers should be able to stretch to around 23 mpg. Surprisingly, the 628 is less economical than the original four-speed 633 we tested which returned 20.8 mpg. But even this latest figure is competitive when compared with those of our chosen rivals (which vary from the Jaguar’s 13.5 to the Porsche 911’s 20.4).

   Whereas the more sporting 635 CSi uses a close-ratio five-speed gearbox, where first is selected by moving the lever across to the left and back – considered awkward by many drivers – the 628 uses the five-speed Getrag gearbox from the 735i. This has a conventional ‘H’ gate for the lower four gears with the overdrive fifth to the right and forward.

   Though the gearchange retains that slight rubbery feel that has always been a feature of bog BMWs, it is precise and extremely slick and complemented by a progressive clutch and well-engineered throttle linkage. The synchromesh proved unbeatable and once mastered, the movement of the stubby mushroom-headed gearlever is one of the delights of driving the 628.

   Unlike the 735i which suffered from excessive gear whine in the lower ratios, the coupé’s transmission is extremely quiet. The lower ratios themselves are fairly widely spaced and at 6,500 rpm, the in-gear maxima are 36, 62 and 98 mph. With fifth gear giving a long-legged 25.8 mph/1000 rpm, cruising at 100 mph is relaxing and seemingly effortless as the engine is spinning at just under 3900 rpm.

   The power-assisted ZF recirculating ball steering is sensibly weighted and every bit as confidence-inspiring as a good unassisted set-up, yet it makes light work of turning the wide Michelins at parking speeds. The steering feels particularly direct for the car understeers very little in the dry and turns readily in response to the helm. Generally, the car adopts an impressively neutral attitude through the majority of corners, though there is sufficient power to push the tail out on tight bends if desired. Long, fast corners can be taken with confidence and on a motorway at speeds, the 628 is impressively stable.

   On good surfaces, the BMW’s ride is well-damped and comfortable while retaining a characteristic firmness which betrays the car’s sporting background. The suspension is only caught out over broken surfaces when potholes cause the body to jar harshly, but to some extent, this sounds worse than it really is. The 628 also suffers less from fore and aft pitching on long-wave undulations, a shortcoming of the 633.

   With 10.7 in ventilated discs at the front and 10.7 in non-ventilated discs at the rear, and with high-pressure hydraulic (not vacuum) assistance, the coupé’s braking system is as good on the road as it is on paper. The brakes are powerful and free from fade, though the pedal does have a slightly ‘mushy’ feel to it when depressed slightly. Braking from high speed in the wet can occasionally result in the front wheels locking prematurely though in the dry they are superb.

   In terms of accommodation, the 628 is very much a two-plus-two, despite its large overall dimensions. By saloon car standards, the rear seats are extremely cramped for adults and even if a compromise is reached with the front seat occupants, then most passengers of average height will still find their head touching the headlining. That said, there is still more rear-seat room than in the Ferrari, the Porsche and the Jaguar. The seats themselves are comfortable and well-shaped yet probably more suited to youngsters. In the front though, there is plenty of leg- and headroom and with the front seats adjustable for height, tilt, backrest rake, and a steering column that telescopes, most drivers should be comfortable behind the wheel. Inside the car there is plenty of storage space for oddments – though not on the centre console – and at 12.5 cu ft, the boot is enormous by coupe standards.

   Comprehensive and clear instrumentation, housed in a binnacle beneath a single pane of clear plastic which is not entirely reflection-free is retained for the 628.

   All-round visibility is excellent thanks to the low waistline and slim roof pillars together with the electrically-adjustable driver’s and passenger’s door mirrors, fitted as standard. The headlamps are powerful on main beam, but rather weak on dip, and the wipers, although excellent in their sweep, are much too slow on their fastest setting.

   One of the car’s other shortcomings, which has gone unchanged since the 6-series was introduced four years ago, is the heating and ventilation system. It is possible to get lots of heat but the temperature control is unprogressive and slow to respond to changes. The result is a rather stuffy interior which is not helped by the lack of throughput from the ventilation system under ram effect alone.

   The generally quiet booster fan helps but unless it is switched to its fastest and noisiest setting, the flow of cold air is poor. In addition, the range of directional control afforded by the ‘cheese cutter’ ventilation grilles is marginal.

   Although the 628 is the quietest 6-series BMW we have tested (72 dBA at 70 mph for example), it is still no match for the Jaguar XJS in this respect. The engine is pleasantly restrained even when revved hard and only coarse road surfaces cause road noise to become obtrusive. Without the optional electric sunroof (£642) fitted to the test car, wind noise would have been even lower.

   As with all current BMWs we have sampled, we were considerably impressed with the high quality of finish. The test car’s seats were trimmed in rich-looking dark blue leather (most of our testers said they would have preferred the optional and more supportive velour trim) with matching carpet. Although wide use is made of moulded plastic inside the car, it fits well and does not look out of place. The body panels also had a good fit and the doors shut with a satisfying ‘clunk’.

   The 628 is well-equipped, though by £16,000 standards, not exceptionally so. Standard fittings include electric tinted windows, front and rear; central locking for the doors and boot; power steering; adjustable seats and steering wheel; alloy wheels with steel radial ply tyres; a comprehensive tool kit; and the choice of either leather or velour trim, uprated suspension and Recaro seats.

   Optional extras on the 628 include automatic transmission (£360); an electric sunroof (£642); headlamp wash/wipe (£211); air-conditioning (£1,212); a limited slip differential (£231); a cruise control (£342) and metallic paintwork (£337). A radio/cassette player is also an extra.

Maximum speeds

   Acceleration from rest

Acceleration in top and in 4^th (sec)