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Rover Mini - Product in Detail

ENGINE AND TRANSMISSION

Mini was designed in an era when legislation was scarcely more than compliance with Construction and Use Regulations; its 'A' Series engine had been designed even earlier. It is a tribute to all engineers involved then and now that the 1997 Mini has been able to meet the very demanding 'ECDII' emissions standards in addition to the new pass-by noise requirements. Significant engineering changes have been made to achieve these environmental standards, making the 1997 cars the most technically sophisticated production Minis ever.

The major change to the 1275cc Cooper engine, now standardised in both 1997 models, has been the adoption of multi-point fuel injection. The system is controlled by Rover's most powerful engine management computer, the MEMS 2J, (as developed for the 2.5 litre KV6 and the MGF 1.8i VVC engines) to give fully programmed sequential injection. Each injector is pulsed at the optimum time to independently fuel the two cylinders that it serves. This provides the ultra-precise control of fuel input and distribution needed to achieve very low emissions, whilst at the same time maintaining excellent performance.

Another contributory state-of-the-art feature is the fitment of a direct (distributor less) electronic ignition system. This uses quad dry-coil twin-spark technology, triggering each spark twice - once on the compression stroke and once on the exhaust stroke - so that the high tension voltage does not have to be switched between cylinders. The cylinder block has been modified to delete the distributor housing, redesign the oil galleries and also to re-locate the oil filter (deleting the external pipe work). This has allowed the radiator to be moved from its traditional side mounting to a more conventional position in front of the engine as part of the pass-by noise reduction programme. Other technical improvements under the bonnet include the replacement of the former 45 amp alternator with a 65 amp unit and the use of a modern poly-vee belt alternator/water pump drive for greater durability and reliability.

PERFORMANCE AND ECONOMY

Despite being the 'cleanest' 'A' Series engine yet, the 1997 Mini engine matches the power and torque figures of the previous Cooper unit, doing so at lower engine speeds. For lower internal noise levels, a 2.76:1 final drive ratio raises the overall gearing by 16% compared to the previous Mini Cooper and this, coupled with an inevitable weight increase of around 3.5%, means a slight reduction in 'on paper' performance. The figures, however, remain very competitive and the subjective impression of the power delivery is excellent.

With fourth gear now equivalent to fifth gear on many other cars and a third gear high enough to virtually achieve the 90mph maximum speed, the driving characteristics are very different. The 'overdrive' fourth gear cuts engine speed at 70mph from 3,888 rpm to 3,333 rpm for more comfortable cruising, while third gear now provides the upper range acceleration and overtaking capability.

As a result of the significant power unit modifications, automatic transmission is no longer available.

Fuel Consumption


In common with all models homologated since January 1st 1996, the 1997 Minis must, by law, have their official fuel consumption figures stated in the new 93/116/EC standard format. This is comprised of a new 'Urban' cycle, which now includes a cold start, a new 'Extra Urban' (meaning 'out of town') cycle and a 'Combined' urban/extra urban figure which is an average of the two figures weighted by the distance covered in each cycle.

It must be stressed that the new figures cannot be compared in any way with the previous Urban/56mph/75mph figures, or any of their various 'composite' and 'Euro mix' derivatives.

The new tests are completely different and are intended to give a more realistic representation of normal car use. As before, however, they still only form the basis for comparison between different cars, as no standard test can possibly tell a given customer what fuel consumption he or she will achieve.

The fuel economy figures for the 1997 Minis are as follows:

Urban 33.4 mpg (8.5 l/100 km)
Extra- Urban 51.8 mpg (5.5 l/100 km)
Combined 43.0 mpg (6.6 l/100 km)

SAFETY AND SECURITY

Sector leading Safety
 

In keeping with the enhanced specifications of the 1997 Minis, a comprehensive new safety package has been standardised. This includes:

Driver's airbag-equipped steering wheel, fitted to a specially strengthened and newly engineered steering column.
Front seat belt pre-tensioners (actuated by pyrotechnic devices in the inertia reel units)
Side impact protective bars within the doors

This now aligns the secondary safety features of Mini with those of many much larger vehicles and moves it ahead of many other cars in its size sector.

Anti-theft measures
 

In 1997 form, the Mini and Mini Cooper are even more desirable - so it is re-assuring that the standard security system is comprehensive. There is a full perimetric alarm system, plus an engine immobiliser, operated by a remote control. Even if the owner forgets or delays the setting of the system, the engine immobiliser will automatically activate after a few seconds to foil the opportunist thief. A facia warning light flashes once the system is activated to deter unwelcome attention.

REFINEMENT

Mini moves into a new and quieter age with the 1997 models. By combining engineering changes that meet stringent new 'pass-by' noise regulations with substantial improvements to cabin acoustic insulation, the latest Minis have become the most civilised yet.

The EC directive on pass-by noise (92/97/EEC) that all post-October 1996 registered cars must meet, demands a maximum of 74dB(A) measured by a special test procedure. Since the previous limit was 77dB(A), this may not seem a big reduction, but because decibels are plotted on a logarithmic scale, it actually represents a halving of the noise level. Reductions of up to 3dB(A) in the critical 3250-3500 rpm range mean that motorway cruising at the legal speed limit is twice as quiet!

In order to achieve this, the 1997 Minis feature higher gearing, a new front-mounted radiator with electric cooling fan, and a rear exhaust silencer box.

Interior sound deadening measures include damping pads in the roof, plus the extra absorption effect of the new foam-backed fabric headlining which help to tune out the 'boom' effect at higher engine speeds. Extra sound-path sealing around the top of the bulkhead and the A-post areas keeps engine noise out and there is new sound insulation around the fuel tank and boot area to eliminate any possibility of whine from the high pressure fuel pump. The rear seat bulkhead is now solid, without the former blanked-off central aperture. Improved acoustic insulation from road noise results from the new moulded one-piece floor carpet.