“Motor Sport” Tests the D.K.W. Sonderklasse — Auto-Union’s Beautifully Equipped Three-Cylinder, Front-Wheel-Drive Two-Stroke
Bedore the war the D.K.W., product of the Auto-Union concern which also built Audi, Horch and Auto-Union cars in Germany and gave Mercédès-Benz a run for its money in G.P. racing, had an enthusiastic following amongst economy-car users in this country.
Consequently, news of a post-war three-cylinder D.K.W. was received with interest and last March Motor Sport published technical and performance data relating to it.
I have since been able to drive one of these cars, which was lent for test by D. A. and W. H. Aldington, of A.F.N. Ltd., the British concessionaires for these very individualistic cars.
In an age of design uniformity, arising from the mass-assembly rather than construction of popular models, discerning enthusiasts can be excused for turning to vintage and near-vintage vehicles to satisfy their desire for motoring individuality. However, as Bill Shortt’s wife once remarked to me, many modern cars can prove just as intriguing under detailed dissection as vehicles in the vintage tradition. What she implied was that the development story, interchangeability of parts, the effect of obvious engine modifications, and data relating to the adoption of different gear ratios, tyre sizes, etc., add up to a fascinating study whatever the age of the car under discussion. Even so, individuality is sadly lacking in most of today’s vehicles, and in an age of proprietary-uniformity the D.K.W. Sonderklasse from Ingolstadt stands out a mile as a car for the connoisseur.
No car is perfect, not even those in the fabulous-price brackets, and I concede that a Sonderklasse isn’t the cream in everyone’s coffee. Yet, when all is said, as it is about to be in this test-report, I can name no other small car which blends so palatably the ingredients of high quality, vivid performance and individuality.
Incidentally, how nice to see the four-ring Auto-Union badge retained; so many manufacturers seem ashamed of their pre-war badges that have tradition behind them.
This latest D.K.W. is technically different — two-stroke, 896-c.c., three-cylinder power unit, front-wheel drive, transverse-leaf-spring suspension and transmission incorporating a free-wheel. However, I am not so concerned here with the paper specification as with how the Sonderklasse impresses those enthusiasts seeking fast, comfortable transport.
The example into which I stepped at Isleworth was a fixed-head saloon which had completed about 1,000 demonstration miles. I took it over in one of those rainstorms which have characterised the summer of 1954, and was soon aware that not a drop of water enters the body and that the ducted-air type a interior heater blows truly effective gusts of hot air out of the demister vents — and round the legs if you open two charming little doors on the heater box.
Going to the City sufficed to bring at least partial familiarity with the “back-to-front” positions of the steering-column gear lever; during this drive I kept the free-wheel out of action but later, devouring A 41 in the hope of arriving at the excellent Witch Ball Hotel at Whitchurch in time for dinner, I had the little car cruising habitually at 70 m.p.h. and found the hydraulic brakes entirely adequate for rapid retardation with the free-wheel operative.
This cruising speed is accomplished with scarcely a trace of effort from the three-in-line two-cycle engine, which in any case is merely idling for much of the time, thanks to the free-wheel, and the Sonderklasse eats up the miles in a very willing manner. Acceleration is exceedingly good providing proper use is made of the four-speed gearbox, although even in top gear front 20 m.p.h. upwards there is appreciable urge. The step-off in first gear is quite meteoric and a quick change-up into second gear maintains this initial rapid pick-up. The speedometer is marked with limits of 18 m.p.h., 30 m.p.h. and 50 m.p.h., respectively, as the normal limits in the indirect gears, and 75 m.p.h. for the maximum in top gear, but if unchecked the needle will sweep to 60 m.p.h. in third gear without any apparent harm resulting.
On first acquaintance the gear-change isn’t altogether pleasant, because the lever moves up from first to second and down and forward for third gear, up to select top; so that most drivers tend, at first, to swop smartly from second to top gear, which, as the diminutive engine possesses very little low-speed torque, is disastrous to acceleration. Naturally, the D.K.W. pilot soon learns his gear positions and remembers to pull the lever, which is pleasurably light and rigid, towards him with the tips of the fingers of his left hand when selecting the lower ratios and to press it down to engage the higher ones. There is excellent synchromesh to aid him. Reverse gear position is safely on its own, behind second. There is very slight, not unpleasant, gear noise.
It is difficult to engage bottom gear both with the transmission “solid” or the free-wheel in use unless the car is stationary, but this is scarcely a disadvantage. With the free-wheel, selected by a white knob by the steering column, in use, any other gear can be preselected with extreme ease and rapidity, the roller-type free-wheel making no complaints about taking up the difference in revs, as overrun changes to drive. Use of this delightful free-wheel gives smooth coasting on the over-run, the four-stroking from the engine only faintly audible, to match the smooth, turbine-like running of the two-stroke engine under load, and as the brakes cope so admirably and there appear to be no ignition or carburational objections to allowing the revs, to zero for appreciable periods, a D.K.W. owner will normally free-wheel permanently, except perhaps over snow and ice. The car rolls smoothly, too, as Continentals usually do.
Admirable is not an extravagant term to apply to the brakes, which act surely, silently, progressively, yet which arrest the car like the proverbial “giant’s hand” under firm but not excessive pedal pressure. It is debatable whether the friction-free, low-compression engine is able to augment these to any extent even if the transmission is locked, so this department of the Sonderklasse deserves praise as being fully complementary to the free-wheel. The central pull-up hand-lever, with its good ratchet-release button, is, perhaps, set rather low; this comment, however, comes from one whose hands are known to lose themselves in ready-to-wear shirts! In a compact car which is as happy at 70 m.p.h. as at any other speed and which possesses excellent acceleration and powerful vice-free brakes, it is pleasant to find roadholding, steering and cornering qualities in keeping. Moreover, a very full load does not affect these qualities.
The suspension, by transverse leaf springs and independent at the front, is well damped by double-action telescopic shock-absorbers but allows rather too much up-and-down motion, of a decidedly lively sort, over the rougher roads. Occasionally this can be disconcerting when cornering fast, but otherwise the Sonderklasse corners well, in a style of its own, with emphasis on slight over-steer, varying with drive and over-run, but very safely and accurately, with a minimum of roll and tyre howl.
The rack-and-pinion steering asks a shade over 2 1/2 turns lock to lock, the turning circle rather large, but in practice is sufficiently quick to be pleasant, firm rather than light, with not a trace of lost-motion or sponginess to mar its accuracy, and transmitting no road shock but some vibration; some snatching, too, is felt when accelerating hard in the lower gears. The presence of front-wheel drive, however, would otherwise not be suspected. The castor-action is vigorous only when accelerating. This is steering that makes darting through gaps in traffic joyful and safe.
Forward visibility is good although both wings are not normally visible. The rear window, in American style, affords even better visibility at the expense of displaying the back-seat passengers in shop-window fashion, but the sloping screen pillars are rather thick. The bucket front seats, beautifully made and with deep, fold-forward squabs, are comfortable but rather more rounded back rests would offer better support when cornering fast.
All in all, however, the Sonderldasse driver has a comfortable time, even when called upon to maintain “rally-average speeds,” at which the D.K.W. is demonstrably adept.
The excellent controllability, good performance and quiet, effortless functioning are well backed up by luxury appointments. The dash and screen-sill are in very convincing dark imitation-wood plastic, and provided with a cubby-hole with lockable lid, backed up by usefully capacious, elastic-topped door pockets and a generous parcels shelf behind the back seat. The luggage boot possesses very commendable space on a wooden shelf over the fuel tank, and coats, etc., can be stowed on the spare wheel, which is carried horizontally on the floor of the boot. The spring-loaded boot-lid is light to lift, shuts with merely gentle down pressure on the catch obviating any need to slam it), and locks; rain-water unfortunately enters the boot when the lid is raised on a wet day.
The instruments, before the driver, consist of a Vdo 90-m.p.h. speedometer with total mileage recorder reading to the nearest mile but no trip-reading, a square-dial Vdo clock and a combined dial showing fuel level, water temperature and having warning lights for direction indicators and headlamps’ full beam, the latter sensibly small and of blue anti-dazzle colour. The speedometer has a very steady needle, the instruments have tastefully-finished, high-quality dials, and the clock a central knob for setting its hands; the gold numerals are not altogether easy to read in sunlight. Flanking the dials are three delightful little pull-push switches controlling the very effective, self-parking screen-wipers, subdued dash-lighting and dual roof-lamps, respectively. Comparing these remarks with those we are sometimes compelled to make will indicate the good taste of the D.K.W.’s minor appointments, but there are other refinements. For example, the roof-lamps light when the doors open, regardless of switch or ignition-key settings, the ignition key locks the steering for safe parking (on the car tested it proved very stiff to withdraw and wouldn’t fit the cubby-hole lid lock), and a delightful little chain hanging from the facia varies the setting of the radiator blind (actually, this is an extra), the links engaging the chain-guide to hold the blind in any desired position. The direction indicators are controlled by a little lever protruding from the right of the steering column (they are not self-cancelling, which is surprising in view a the other appointments; they work noisily and that on the near side became inoperative while we had the car). The starter is controlled by a tiny button beneath the ignition key (again, delightful!), and the ignition reminder light is above the key; the pull-out choke-knob is scarcely required, at all events in summer. There is an ash-tray in the centre of the screen sill, and another for the back-seat passengers, both with neat lids, and provision for a facia radio. A neat detail is the presence of a cover for the door lock.
The built-in headlamps provide an excellent beam and dim effectively. The pull-out lights-switch is below the three other pull-out switches and identified by having a larger knob. There is the excellent Continental-pattern dipping lever extending from the left of the steering column, but this lever could be an inch or so longer with advantage; it does not select side-lamps only, as on a Citroën, for example.
The horn button, in the centre of the white, two-spoke steering wheel, controls a usefully-commanding horn, and there is a small, but reasonably adequate, rigidly-mounted rear-view mirror. Twin anti-dazzle vizors are provided, the white fittings on the facia reflecting in them rather drastically.
The seats adjust and lock easily, the doors shut rather “tinnily” but seal effectively on rubber beadings, and there is a socket near the driver for cigar-lighter or lead-lamp.
It is difficult to convey in words the sense of security and well-being which these fine interior appointments, deep screen-sill, comfortably upholstered (plastic) seats and heavy doors impart. The doors have hinged ventilator windows and not only their main windows (which are metal-framed and slide firmly in thick rubber seals) but, the curved back lights also, wind down, the action in respect of the latter being distinctly ingenious, and 100 per cent. ventilation ensues when all are wound down. The winder handles are securely mounted and their knobs are pivoted, but opening a window on the D.K.W. is reminiscent of lowering the undercarriage of an Avro Anson, so low-geared is the mechanism! Arm-rests are provided in the doors and for the back-seat passengers.
The exterior finish is by furnace-dried synthetic paint, or sprayed nitro-cellulose for the convertible bodies, the roof having a different hue from the rest of the car. The spring-loaded alligator bonnet is easily opened from the front of the car (no facia control) to reveal the three-cylinder, 34-b.h.p. engine with its light-alloy head and water-pipe castings, and substantial tunnel for the shaft of the belt-driven, multi-bladed cooling-fan, which is ahead of the pressurised, behind-engine radiator. The radiator filler is accessible, as are the Exide battery and the 12 fuses in their neat metal “coffin.” The grille also detaches to facilitate maintenance. At the back the fuel tank filler is of generous size, but its cap is unsecured after removal. Fuel is fed to the Solex Type 40 JCB downdraught carburetter by a Solex vacuum pump. The three separate Siba ignition coils feed Beru (or Bosch) plugs. The other electrics are Bosch. A very accessible wing-nut provides for clutch-pedal clearance adjustment — another practical D.K.W. feature.
The two-stroke engine is not temperamental, and gave no trouble of any sort. There was at times a very “hot smell,” noticeable from outside the car with the bonnet closed and to some extent by the occupants (brakes?). The exhaust is visibly smoky. With the radiator blind partially up temperature never rose above normal. Slight pinking was induced by using cheap fuel and, normally, premium petrol was employed. S.A.E. 50 oil is mixed with the petrol for lubrication purposes in the proportion of a pint per three gallons. This caused us no particular inconvenience, and future Sonderklasse cars will have an automatic mixer incorporated in the tank. Although at first sight the oil consumption, at approximately 670 m.p.g., seems heavy, it must be remembered that no sump draining is called for with total-loss lubrication, nor does consumption increase appreciably as engine wear takes place; Moreover, oil is present on the cylinder bores when it is most needed immediately after starting. Four-stroking is only evident at idling r.p.m. Moreover, the oil reaching the internals is always clean oil.
Fuel consumption proved rather a disappointment, of which the rapid sinking of the fuel-gauge indicator towards the section of the dial marked RES. gave a foretaste. A check mostly at fast main-road cruising, using all the available acceleration, gave a figure of 26.5 m.p.g. Taking matters more easily improved this to 29 m.p.g., and the average over 429 miles was 26.8 m.p.g. and just over five pints of oil. It must, however, be admitted that 70 m.p.h. was held for mile after mile and larger cars disposed of as if they were standing still, and high performance nearly always has to be paid for in terms of fuel. It is usual to refuel with three or six gallons at a time to humour the oil content, and as the tank holds only seven gallons, the needle of the fuel gauge is naturally apt to look mostly pessimistic. The fuel system primes on a very small head of fuel after the tank has been drained.
A very comprehensive instruction book, illustrated with excellent photographs, comes with the car (it contains one amusing mistranslation: “pre-ignition,” for “ignition advance”).
I enjoyed very much the 700 miles of Sonderklasse motoring I experienced. In this new 896-c.c. D.K.W. the enthusiast will discover a car which is individual to a marked degree, which responds well to skilful handling, and which in respect of safe, exhilarating, Continental-style, fast motoring, makes cars of many capacities look smaller than itself. It is one of those rare cars which give pleasure when stationary, because of its many unique and practical features, as well as in action.
The D.K.W. Sonderklasse is not inexpensive either to purchase (it costs £948 17s. 6d. in this country inclusive of p.t.) or to fuel, but to those who can afford such a car it represents a beautifully-appointed high-performance vehicle of charming character and compact dimensions.
I have no doubt that the Aldingtons will gladly demonstrate on the road what I have endeavoured to convey in cold print. After a very enjoyable fast journey to Oulton Park and elsewhere, this unbiased critic found himself becoming more and more of a Sonderklasse convert as each mile slipped enjoyably by in the wake of a faint haze of blue smoke. — W. B.
[N.B. — That the D.K.W. Sonderklasse is an individualistic possession is emphasised by the fact that while we drove the test-car we saw only one other of the species, a utility-bodied version. But the car is beginning to sell over here. Apart from the saloon, a four-seater, fixed-head coupé is available for £692, a four-seat convertible for £812 and a two-seat coachbuilt convertible for £908; p.t. extra.]
The D.K.W. Sonderklasse 3-6 Saloon
Engine: Three cylinders, 71 by 76 mm., 896 c.c., two-stroke; 6.5 to 1 compression ratio; 34 b.h.p. at 4,000 r.p.m.; maximum r.p.m. = 4,350.
Gear ratios: First, 18.0 to 1; second, 10.45 to 1; third, 6.3 to 1; top, 4.25 to 1.
Tyres: 5.60 by 15 Michelin Super-Comfort on bolt-on, steel disc wheels.
Weight: 17 cwt. (ready for the road, without occupants, but with two gallons of petrol).
Steering ratio: Two and a half turns, lock to lock.
Fuel capacity: Seven gallons; range approx. 188 miles.
Wheelbase: 7 ft. 8.51 in.
Track: Front, 3 ft. 11 in.; back, 4 ft. 1 in.
Dimensions: 13 ft. 10 in. by 5 ft. 3 in. by 4 ft. 9 in. (high).
Maxima in gears (maker’s figures): —
1st … 18 m.p.h.
2nd … 30 m.p.h.
3rd … 50 m.p.h.
Top … 75 m.p.h.
Price: £669 (£948 17s. 6d. with p.t.).
Concessionaires: A.F.N. Ltd., Falcon Works, London Road, Isleworth, Middlesex.