To place the K70 we have to look briefly back into NSU history. When NSU marketed the R080 they were aware that its public acceptance might be a bit of a gamble, that they still had a great deal of piston engine manufacturing machinery to use and that there was a vast price gulf fixed between the inexpensive rear-engined models and the costly rotary-engined car. All this pointed to an intermediate model with a piston engine and this is how the K70 was born. It was announced very early in 1969 for the Geneva Show and then withdrawn again when VW took over NSU and formed the new subsidiary called Audi NSU Auto Union AG in April 1969.
Withdrawn but not suppressed. On the contrary, VW thought it was such a good car that they decided to give it their own name and produce it in very much larger numbers than NSU could possibly have afforded. In the meantime they have built a new factory at Salzgitter, not far from Wolfsburg, with a potential capacity of 500 K70s a day. And, of course, development has been continued by both NSU and VW.
We described and illustrated the K70 early this year (Motor, w/e March 7). To recapitulate briefly, it is designed very much after the lines of the Ro80 with front-wheel drive, a very long wheelbase and wide track, a short overhang body with rather similar lines, MacPherson Strut front suspension and irs by semi-trailing rear wishbones and coil spring /damper units. It has anti-roll bars at both ends, inboard disc brakes at the front and outboard drums at the rear with a pressure limiting valve and dual circuit operation. Steering is by rack and pinion but unlike the R080 (and contrary to earlier reports) it does not have power assistance.
The big difference, of course, is in the power unit which has a strong family resemblance to that of the Prinz 1000 series (but water-cooled) with a single chain-driven overhead camshaft operating V inclined valves in hemi-spherical heads through rocking fingers. The engine axis is longitudinal, the four-speed, all-synchromesh, all-indirect gearbox is behind the engine and the final drive is underneath it. Because of this the Ro80’s low bonnet line is not possible, even though the engine is canted 32° to the right to keep it low.
Two versions of the 82 X 76 mm. short stroke 1605 cc engine are available, both with five main bearings and a twin-choke side—draught Solex carburetter; one version has a compression ratio of 8:1 and gives 75 bhp (net) at 5200 rpm on 90 octane fuel, the other with 9.5 ratio needs 98 octane but gives 90 bhp at the same engine speed.
So much for the broad outline. Of course the last 18 months’ extra development has brought some further changes to the original design but most of these are of a very minor nature. The wheel size, however, has gone up from 13 to 14 in. and the 4.5j rims have 165SR radial tyres. Many of the engineering modifications have been inspired by VW’s production expertise and of these the most conspicuous is the change from a light alloy to a cast iron cylinder block.
The first public appearance of the K70 will be at the Paris Show but we recently had the chance to drive it for 150 miles in France. The question which obviously arises is, how does it compare with the Ro80, a car which has had rave test reports all over the world? In some ways it compares very well—it is a roomy five-seater car with an enormous boot of 24.5 cu.ft. capacity. It isn’t, of course, as fast. VW claim a maximum speed of 98 mph for the higher·powered version as against our test figure of 113 mph for the rotary car although the 0-60 mph figures are very similar. Road noise is very low and the K70 has that rigid, rattle-free feeling which adds so much to driving enjoyment on rough roads. The ride is generally good although it is characteristic of stiffly damped cars—a bit jerky at low speeds, but smoothing out at higher speeds.
Wind noise is also low and the ventilation system, a high flow, low velocity system, gives a draught-free air movement which is all you need up to quite high ambient temperatures. The engine is not as smooth as a Wankel but for a piston engine it is very smooth at high rpm, even if you take it right up into the red sector at 7000 rpm.
Probably the most disappointing feature relative to the Ro80 is the handling; the car is unusually stable, predictable and vice-free but the Michelin ZX tyres squeal at quite low cornering speeds and understeer builds up as you go faster until you can find yourself practically on full lock on sharp bends. We would want to try higher tyre pressures than the recommended 21 lb. all round—certainly much higher at the front on a car with 60 per cent of its unladen weight at this end.
Right hand drive K70s will not reach the UK until October 1971. In Germany, where the first batch will all be sold, its chief competitors will ironically be two other products of the VW group—the VW 411E and the Audi 100. No British price is yet available, of course, but the best possible estimate would put the current price at about £1600; in a year’s time it will probably be higher. Excellent though it is in many ways, it isn’t sufficiently distinguished we feel to command large British sales in this highly competitive price category. CHB
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