Four-Wheel Drive for New Alfa Romeo 33 Flagship — Press Release

Alfa Romeo has completed its 33 range in the UK with a technologically-advanced new high-performance four-wheel-drive model, the 33 S 16V Cloverleaf Permanent 4.

Combining Alfa Romeo's acclaimed 1.7-litre, 137 bhp, 16-valve 'boxer' engine and permanent four-wheel-drive transmission, the exciting new flagship 33 breaks new ground in the crowded 'hot hatchback' arena.

No other manufacturer offers a more sophisticated transmission system with such a powerful engine in this market sector. Furthermore, the Permanent 4's comprehensive equipment level emphasises its outstanding value for money.

Aimed directly at the younger enthusiast driver, the 126 mph Permanent 4 accelerates to 60 mph in 8.5 seconds and provides the handling, roadholding and general driving satisfaction of a true sporting car together with the enhanced safety of four-wheel-drive in a thoroughly practical five-door body.

Alfa Romeo's state-of-the-art four-wheel-drive transmission gives unusually high levels of road grip in normal driving conditions, and unprecedented levels of traction and security on uneven or slippery surfaces.

Sophisticated technology ensures that tyre wear is no greater than conventional two-wheel-drive transmissions, and near
identical fuel economy.

The transmission features a Ferguson-type 'viscous coupling' within the centre differential, which allows the drive from the gearbox to be continuously and automatically varied between the front and rear wheels.

In normal driving conditions, where traction is plentiful, 95 per cent of the engine's torque is fed to the front wheels in order to minimise friction and maximise economy. However, as soon as any traction loss is detected, such as under hard acceleration, torque is progressively transferred to the rear axle.

This system allows the optimum exploitation of the 16-valve engine's high output on all surfaces, giving the car not only leech-like road grip, but also superb balance and poise through corners.

On wet or icy roads - or even in a muddy field - the viscous coupling demonstrates its superiority over less sophisticated differentials. By sensing which axle has the better grip, and then supplying the appropriate level of torque, it prevents wheelspin that could unbalance the chassis under hard cornering or acceleration, or, at worst, immobilise the car.

Even in normal town driving the benefit of four-wheel drive can be felt. For instance when pulling out of a junction on a wet road the transmission will ensure there is no wheelspin, and no subsequent steering reaction.

This variable 'torque-split' is possible because the viscous coupling operates by way of a series of coaxial discs mounted in a silicon fluid filled casing. Any rotational difference between the front and rear axles is detected by the discs, which shear through the liquid silicon at different speeds and change its viscosity. This progressively supplies more torque to the axle with the best access to road grip.

Under severe braking, when conventional four-wheel-drive arrangements may encourage all four wheels to lock, the Alfa Romeo system incorporates a fail-safe electromagnetic clutch, to disengage drive momentarily from the rear wheels.

This solenoid coupling, positioned ahead of the drive shaft, is governed by an electronic control unit. Under sharp braking, the microprocessor is programmed to cut drive to the rear axle, restoring it one hundredth of a second after the brake pedal released.

To avoid synchronisation problems, drive is only re-connected if the angular speeds of the solenoid's two gears is not excessive. If this is the case, the ECU momentarily prevents engagement, repeating the attempt every three-tenths of a second until the operation is successful.

The Permanent 4's classic 1,712 cc horizontally-opposed 16-valve quad-cam engine shares the same advanced mechanical specification as the unit used in its front-driven stablemate. Fuelling is by the ultra-sophisticated Bosch Moronic ML 4.1 digital electronic injection system which has integrated ignition and engine management microprocessors.

The engine's 137 bhp is produced at 6,500 rpm, however Alfa Romeo's multi-valve engine provides more than out-and-out pace, for the plentiful 118 lb ft of torque at 4,600 rpm ensures excellent flexibility in town driving.

Despite the Permanent 4's sporting engine tune, it still returns over 47 mpg at a steady 56 mph, running on either leaded or unleaded fuel.

Suspension is by independent front McPherson struts with transverse lower wishbones and anti-roll bar, with a rear tubular axle located by twin wishbones, Panhard rod and coil springs.

High-performance braking is guaranteed by the use of a servo-assisted all-disc system, with internal ventilation at the front.

The gearbox is the same as that used in the front-drive 33 16V, with the five forward gears close-set to maximise the sporting response of the boxer engine.

To match the overtly sporting nature of the Permanent 4, and to provide the driver and passenger with the ultimate location and comfort during spirited driving, deeply contoured Recaro seats, with variable under-thigh support, are fitted as standard. A Nardi leather bound sports steering wheel, which is adjustable for height, also contributes to driver appeal.

Standard equipment on the 33 S 16V Cloverleaf Permanent 4 includes speed-sensitive power-assisted steering, 14-inch light alloy wheels shod with low-profile 185/60 HR14 tyres, tilt-slide sunroof, high-pressure headlamp washers, front fog lamps, electric front windows, central locking, tinted glass, adjustable upper seatbelt mounts and a four-speaker stereo radio/cassette unit with roof-mounted aerial.

The 33's contemporary lines are enhanced by a number of sporting additions, though the overall appearance remains discreet. The grille and door mirrors are colour keyed, while a rear bootlid spoiler and side sill extensions and deeper front spoiler are specified. The design of alloy wheel mirrors the pattern of those fitted to the 148 mph Alfa Romeo 164 Cloverleaf.

Naturally the 33 S 16V Cloverleaf Permanent 4 features the recent extensive interior revisions made to the entire 33 range.

The facia - fashioned with the aid of computer-aided design - contains clear and attractive instrumentation. There is also a much improved heating/ventilation system, with 10 separate outlets. An air recycling mode prevents traffic fumes entering the cabin.

Convenience features include a remote release for the tailgate, remote adjustment for the door mirrors, and a lights-on warning buzzer.

The Permanent 4's uncompromisingly sporting mechanical specification belies its practical nature. As standard there is an asymmetrically-split folding rear seat, so that long narrow loads can be carried without committing the entire rear seat accommodation.

As with all Alfa Romeos, the 33 S 16V Cloverleaf Permanent 4 comes with a comprehensive 12-month unlimited mileage factory mechanical warranty, and a six-year anti-corrosion guarantee. Additionally, major servicing at 12,000 mile intervals further reduces the cost of ownership.