Mini Cooper S

Introduction

In 1963, racing specialist John Cooper helped BMC to develop a hot version of Mini, which employed a bigger engine, tweaked suspension and wider tyres. The Cooper-Mini S - in either Austin or Morris guise - was originally put into production to get the model homologated for competition. A thousand units were envisaged, and the car was seen primarily as a competition mount

The Mini Cooper had already increased power from the then new 997cc (later 998cc) motor from 34 bhp to 55 bhp which resulted in speeds of 139 km/h being achieved - and which was seen as quick enough to warrant tiny front disc brakes. When the Mini Cooper S was released in 1964 it used a 1071cc, then 1275cc engine boasting around 70 bhp and capable of nearly 160 km/h.

Not surprisingly, it was successful, and demand was so high among ordinary motorists, that it was put into full-scale manufacture. Although it cost £128 (sterling) more than the normal Cooper-Mini, it was worth every penny of the extra. For £695 (stg.) you would have a car that was pretty much the fastest performer over England's crowded and twisty roads. Even on the motorways it was unlikely another vehicle would be capable of overtaking an S.

Rapid Acceleration

The acceleration of the S was extrodinary, and it had an uncanny ability to weave in and out of traffic, be it around town or even on the race track. The speedometer ran to an indicated 100 m.p.h. when the true speed (of the original 1071cc engined versions) was 94. Even so, a maximum of around 95 and a 0-60 m.p.h. figure of 13.5 seconds made the fourseater a powerful car by any standards.

Owners were soon claiming 0-70 miles-per-hour times of 17 seconds flat, and a 0-80 in 25. From 30 to 50 in top was around 8.5 sec. and 40-60 again in top, 9.0 sec. A genuine 80 m.p.h. was available in third, yet such was the flexibility of the car that it was possible to accelerate from 10-60 in top in 19 sec. without ping, snatch, or any sort of complaint. Brilliant.

Dr Heckle & Mr Hyde

Yet the Cooper-S was a Dr Heckle & Mr Hyde. It was equally at home as a sweet-running family car that could be used for the annual holiday, shopping, or touring. It just happened that it was also a true enthusiast's car for racing or rallying. The British Motor Corporation played along with this by offering a choice of two gearbox internals providing two different sets of ratios; there were two final-drive ratios available (3.765 or 3.44:1) with either box, and then there was a choice of two wheelrim widths - 3.5 or 4.5 in. Both were fitted as standard with Dunlop's exceptional SP braced-thread tyres, the choice of rims offered a wide track (4ft. 17-32in. front; 3ft. 115-16in. rear) with the 4iin., and a standard track of 3ft. 11 17-32in. front; 3ft. 10 5-16in. rear.

If you opted for the narrower rims with low final-drive ratio and high third gear you would realise the Mini was fussy about tyre pressures, but once they were as the book said (28lb. front, 26lb. rear) the handling was fully in keeping with the car's performance. If the pressures were down the S would yaw at low speed. At high speed the handling was wonderful, and in the wet the road-holding was uncanny. So good and race-bred was the ADO 15 and its Moulton rubber suspension that it wasn't deemed necessary to change a thing for the 70 bhp engine.

In spite of the 1071cc motor's 70 b.h.p. (at 5750 rpm) and the fact that it used two smallish pancake air filters on the two SU HS2 carburettors, the mechanical and induction noise level remained low. The pistons did not clatter, and the little short-stroke unit was a gem. By moving the windscreen-washer tank up on to the sound-proofed bulkhead, the BMC engineers found room for the fresh air heater trunk and the brake booster on the offside' of the engine. In traffic the Cooper-S could trickle along in top gear and accelerate without fuss or pinging. With a 9:1 compression ratio the Formula Junior-based engine liked a diet of 95-100 octane fuel, but that was the only concession that had to be made to its racing and rally background.

Behind the Wheel

The engine had a bore of 70.6mm. and a stroke of 68.26mm., the over-square ratio made it possible to run the crankshaft to speeds around 7000 rpm with no sign of harshness or distress. Strangely, no rev-counter was fitted - arguably the biggest criticism on a car with so much performance on tap. Driving the car hard demanded something out of the ordinary in the braking line and the Mini S was, proverbially, well endowed. The Lockheed discs were 7.5m. diameter at the front and the rear drums were 7in. by 1.25 in. with leading and trailing shoes, and there was a large servo to assist.

With maximum pedal pressure in neutral you could easily get 1g (30ft.) from 30 m.p.h. For all normal braking, pedal pressures were low, and fade almost non-existant. Fuel consumption wise, you could still achieve better than 28 mpg provided you resisted the temptation to put the foot down. On the highway you could get around 24 mpg - but resisting the temptation to exploit the cars capabilities was more often too hard to resist.

The driving position was excellent, the upright steering column typically Mini, but, in conjunction with the seat shape, allowed the driver to get well away from the wheel and have plenty of room for their legs and feet. The straight gear lever was well placed near the driver's hand and the then new synchromesh (still on three higher ratios only) worked well, permitting very quick shifts to be made with little effort. Road view was in the Mini manner, the large rear window still being wasted with the tiny rear-view mirror as supplied by BMC.

So why the fuss? Turn up to a Mini car show and you will see plenty of smiles on the owners of the Cooper's. And well may they be pleased. In its day the Cooper was a fraction of the cost of a 250GT Ferrari, Rolls-Royce V8, and was even cheaper than a Morris 1100. And which one would you prefer to own today? OK, the Ferrari would be very tempting, but as a reliable and cheap to maintain rig, the Mini was an absolute little ball-tearer. It would win the hearts of many racing fans and, and nobody was surprised that it found success on the racing track - arguably the best being the Monte Carlo Rally. A total of 5.3 million Minis were sold during its 41 years of manufacture. It is to be expected that the most collectable are the Cooper and Cooper S versions.