VW Golf Syncro – Mass Market 4WD?
While several manufacturers have now installed four-wheel-drive in passenger cars. Volkswagen’s Syncro system breaks new ground in a number of ways. First, it is to be fitted to everyday vehicles — Ford, BMW, and Audi all offer 4WD in conjunction with performance or at least executive cars, (the Alfa 33, Fiat Panda and Subaru systems are only part-time) — whereas VW has a Syncro Passat estate, Transporter minibus, and now a Golf.
But “Syncro” does not necessarily mean the same thing in each case. The Passat is equipped with a development of the Audi 50:50 fixed front/ rear split as in the Ouattro, the Transporter has a rear engine with predominantly rear wheel drive, and the new Golf Syncro has, of course, a front engine and retains predominantly front wheel drive. It is that qualifying word “predominantly” which distinguishes the new Syncro system from others so far available.
Although all four wheels are permanently driven, the “extra” pair (front on Transporter, rear on Golf) are effectively ticking over in ordinary driving on level roads, imparting perhaps a mere 5% of the total available torque to the tarmac. Only when the “main” wheels start to slip is the spare torque channelled to the other wheels, not only automatically and without any driver intervention, but much more quickly than human reaction times would allow.
This is achieved through a viscous coupling which connects the new prop-shaft, driven by a bevel gear from the Golf’s front gearbox, to the rear differential. Designed to allow some slippage to compensate for different rotational speeds of front and rear axles during cornering, the coupling stiffens up when the speed difference becomes too great, i.e. when the wheels spin, thus locking the two axles together. But since they are connected only by the medium of silicon fluid the degree of slip and thus the torque distribution is smoothly and infinitely variable, and alters in less than one revolution of a wheel without the driver’s feeling anything.
The viscous coupling is not a differential, since there is only an input and an output shaft rather than the three shafts of a differential, and it is contained in a drum of only some five inches across. Within this are 59 thin metal discs of which every second one is attached to the housing and the remaining alternate discs are splined to the output shaft to the rear differential. Filling the tiny spaces between the interleaved plates is the silicon fluid, which being inorganic retains its qualities at high temperatures and does not age.
New independent rear suspension takes the form of semi-trailing arms with coil spring struts, and the rigidly mounted diff, of small diameter since the final-drive stepdown is taken care of at the front, includes an extra feature which will enable VW to offer antilock braking.
ABS requires all the wheels to be able to rotate at different speeds; if two or more are rigidly connected, say by a solid axle or by a central duff lock, then all the retardation will be done by the tyre with the best grip, with the risk of one of the others locking up. This is why the Audi Ouattro system cuts out ABS while the centre lock is engaged. The problem still applies to the viscous coupling in the Syncro, and VW’s answer is to fit a freewheel device into the rear differential. Because the front wheels always do most of the braking in any car, they slow down faster for a given pedal pressure: the Syncro’s freewheel allows the rear wheels to overrun, breaking the connection front to rear and enabling the ABS to operate.
To avoid disconnecting the rear wheels while reversing, an electropneumatic device triggered by the reversing light switch locks the freewheel to give 4WD backwards as well as forwards. There are no extra controls for the driver to consider, and VW’s claim is that this full-time variable 4WD system is superior to others in normal driving because it is constantly altering in response to patchy traction. Certainly in driving on packed snow, the car feels very stable, though on the launch in Sweden all the cars were equipped with snow tyres, which offered astonishing grip and braking force from high speeds. The problem is that on snow they tend to lock suddenly as the speed decreases to around 20 mph and since none of the cars we tried were fitted with ABS, the sense of security of 4WD and snow tyres can be a false one.
But there is no doubting the traction endowed by the Syncro system, which propels the Golf up extremely slippery slopes without fuss. On a frozen lake, it was possible to spin all four wheels at once and still have directional control; the same slippery surface made the point that the 4WD Golf is, like the 2WD Golf, an understeenng vehicle, but can be pulled round the bend by positive use of the throttle.
Yet the Syncro Golf is not, at the moment at least, being sold with a performance image; it comes in CL specification, with a fuel-injected 90 bhp engine, although it does sport the front spoiler and black wheel-arches of the GTi, and it is some 140 kg heavier. Stronger springs and a 35 mm higher ride height give a little extra ability as a work-horse, but VW point out that while some people will buy it to cope with snow or tow a horse-box, a significant sector will be tempted because of what they term “innovation prestige”
There will be the usual delay before the rhd version appears in Britain — not until the beginning of 1987, but that will conveniently coincide with the introduction of VW’s ABS. Prices are not announced yet, but the Syncro will be dearer than a GTi, which will surely put many potential owners on the horns of a dilemma. The CL engine is efficient and willing, giving the Syncro a 0-62 mph time of 11.3 sec. and while the rear drive-train has resulted in a slightly smaller boot, an asymmetrically-split rear seat goes some way in compensation. There are also larger brakes, but those who seek prestige will have to rely on others’ good eyesight — tiny “Syncro” badges fore and aft are the only signs that when the snow arrives, this Golf will be ahead of the GTi.
All-New Mazda RX-7
Now the only car in production powered by a rotary engine, Mazda’s new manifestation of the RX-7 has moved up the scale both in size and performance, thereby keeping station with the cheapest Porsche. This is an important factor for Mazda in more ways than one.
The new car will retail at a whisker under £14.000, pitching it between Toyota Supra, Alfa GTV6. Isuzu Piazza Turbo and Nissan Silvia Turbo on the one hand and more expensive Porsche, TVR and Lotus models on the other. Yet all these cars are competing for a pretty small sector of the market — less than 1% by Mazda’s reckoning. Even in its best year, the old RX-7, a delightful car found less than 800 customers in Britain: such a proposition offers the parent company a return not so much in direct profits but in reflected glory, or at least interest, for the rest of the range.
This is why the Porsche comparison is important — to be seen as a competitor to the Stuttgart company, which would have been impossible 10 years ago, indicates the progress the firm has made, and implies high quality across the range.
Mazda have made it quite plain that the £16,000 Porsche 924S is a major target, but it is tempting to wonder what impact the new car would have made had it been announced before Porsche put the more powerful 150 bhp engine into the 924. Even two months advantage would have given the RX-7 a head-start which it must now make on its own merits.
And the new RX-7 is a car of merit. At last the bigger 13B engine (which we were told last time round was only for unleaded fuel and so useless for the UK) has been specified, giving the bigger car 150 bhp and taking it from 0-60 in a claimed 8.5 seconds together with a top speed of about 130 mph. Perhaps the bigger unit is a little less smooth than before, but that is still better than most reciprocating engines, and the torque curve is a healthy shape which peaks at 3,000 rpm. The injection system is designed to run 2-star fuel.
Criticisms of the old car centred on the Insensitive recirculating ball steering, now replaced by a rack system, and the sometimes erratic behaviour of the rear suspension. Mazda have gone to great lengths to develop an ingenious linkage controlling the semi-trailing arm set-up which gives a little toe-out to pitch the car into a bend, and then alters to toe-in to produce a stable understeer attitude. It does exactly that, very effectively, but like many sporting drivers I like a car to exhibit a tendency to oversteer on the limit, without having to pitch it sideways, and I did find it a bit frustrating when given the chance to drive the car on the Vallelunga circuit in Italy. As the speed increased, a little more lock was all it needed to remain on line — stable, predictable and showing tremendous grip on its 205/60 VR15 Bridgestone Potenza tyres, but shorn of some of the excitement of its predecessor, despite measurably higher performance.
Interestingly the tyres are unidirectional, which presents a problem to offset the claimed traction advantages particularly in the wet: a mounted tyre must be a right or a left, which should technically mean carrying two spares. In fact, luggage room is not great, so a (Michelin) spacesaver is tucked into the tail panel.
A wide range of adjustments fits the comfortable seats to most drivers, and the dash layout is simple and clear, with a large rev counter in the centre. The rear seats are roomier than before — you might squeeze a ten-year-old in now — and electric windows, mirrors, and sunroof are standard along with the sophisticated Clarion radiocassette.
Deliberately European in styling, the car is most reminiscent of the Porsche 928, with a hint of Chevrolet Camaro at the rear, but the result is attractive and with more presence than the previous model. Visibility is impaired by the thick L-post, but overall it is an enjoyable vehicle to drive, with vastly better steering, more go, and huge vented discs all round with four-pot calipers at the front, all of which refused to fade after an afternoon on the racetrack, usually the Waterloo of any road car.
Ala saving of £2000 over the 924S, the Mazda feels as well-built and as quick, though the German car has the edge in “chuckability” and smoothness of control; those who want one of the 3 or 400 RX7s which will be imported this year will have to order quickly — G.C.
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