BMW introduce the 6-series coupe’
For such an expensive car, BMW’s trendsetting, six-cylinder, two-door coupe series, from 2.5CS to 3.0CSi and CSL, enjoyed extraordinary success, selling 45,000 examples, helped by its image as the touring car racing King of Europe. Production ended last December, rather prematurely we thought, until we were introduced to its 6-series successor in Munich and Marbella. Aesthetically and mechanically the new model shows a worthwhile improvement and keeps BMW well in contention with the opposition, from which, like Jaguar, they single out the Mercedes 350/450SLC as arch-enemy.
Of the two versions of the 6-series coupe, the 3-litre, carburetter 630CS and the 3.2-litre, fuel injection 633CSi, only the latter will be available in Britain—and not until September. Pound and Deutschmark permitting it is likely to cost some £12,000, inclusive of air-conditioning and electric front windows, optional in other markets. In essence, the 6-series follows the same straight-six, independentlysprung path as before, but with many improvements. The body is entirely new, built by Karmann, who’ll also be assembling the cars at the rate of 8,000 per annum, 500 of which will head for the UK. The 3-litre saloons continue unchanged.
Nose styling of the slightly wedge-shaped body comes from the mid-engined Turbo prototype. The vast window area is of Parsol bronze-tinted glass; the side areas are no longer pillar-less, the gap being split by a rollover bar, which helps give better window sealing: The body is designed with safety crush zones and strengthening members and gains 69% in torsional rigidity over the old model. There is some improvement in interior space and the boot gains an extra 3 cu. ft. Although the frontal area change is fractional, aerodynamics are much improved.
The longer-stroke 3,210 c.c. straight-six of the 633CSi gives an identical 200 b.h.p. at 5,500 r.p.m. to the 3.0 CSi. Torque is improved from 200.4 lb. ft. at 4,300 r.p.m. to 209.7 lb. ft. at 4,250 r.p.m. The compression ratio is reduced from 9.5 to 9.0 to 1, but improved efficiency comes from combustion chamber modifications and a change from D-Jetronic to L-Jetronic Bosch fuel-injection. Transistorised ignition is fitted. An extra 40 kg. in weight will probably outweigh any performance gains.
On the chassis side, the track is increased front and rear. At the front the caster angle is reduced and kingpin inclination increased for better direction stability. Instead of separate coil springs and dampers at the rear, spring/ damper struts are fitted, along with an antiroll bar. The ventilated front discs are of 11.0 in., instead of 10.7 in., diameter.
By far the most important chassis improvement is the use of the new ZF-1 ball-and-nut hydraulic steering system, with power assistance varying with engine speed—more power at low speed and vice versa. An appreciably higher ratio is used, too.
Inside, the now familiar BMW curved facia includes an all-systems-go check device: press a button and seven lights should light up if fluid levels and so on are all right.
All seats have headrests, the rear ones including lidded oddments trays. The driver’s seat adjusts for height. An electrically controlled door mirror is a very useful gimmick.
On the German autobahn or in the hills of southern Spain there was no doubting the stability, excellent braking and the high performance of this smooth, 135 m.p.h. straight-six. The handling was excellent, but the suspension too soft in the mountains (there is a stiffer option pack) and we’d have appreciated a limited slip differential, which will be standard on UK cars. Most impressive of all was the precision and feel of the power steering; though a shade more caster return wouldn’t go amiss. Minor modifications to the linkage have improved the gearbox, too.
We look forward to publishing a full road test when this impressive coupe appears on the British market.—C.R.