SHORT HISTORY OF ALFA ROMEO 4X4
first four wheel drive system in Alfa Romeo's history made its debut in 1951 on
the AR51 - 1900, an off-road car with state-of-the-art engineering features
designed for military use.
The 'Matta' (or crazy car - as it was affectionately dubbed by those who
appreciated its exceptional off-road properties) is now a real cult item
appreciated far beyond the restricted circle of Alfa Romeo collectors.
The 33 4x4 made its debut in 1983. The layout adopted for this compact saloon
meant that the rear wheel drive had to be engaged by means of a lever in the
A central differential prevented any slippage between both axles. Because it
offered higher ground clearance than front wheel drive cars, the 33 4x4
acquitted itself well in many critical situations and could pass easily from
snowy surfaces to unsurfaced roads. Altogether a multi-facetted car that allowed
great flexibility of use.
In 1991, the Alfa 33 (again) was fitted with a sportier interpretation of the
four wheel drive concept. The transmission layout of the new Permanent 4 (this
was the name of the version) was more complex than its predecessor: a set of
sensors managed the action of a viscous coupling that transferred movement to
the rear wheels (generally free) when it detected significant differences
between wheel rotating speeds across both axles. These features assured the 33
outstanding dynamic performance, an up-to-date blend of high performance, sports
handling and top level active safety.
The following year saw the arrival of the 155 Q4. The new Q4 name sums up the
spirit of this car, which sets out to represent the state of the art achieved by
Alfa Rome in terms of technology geared to driving satisfaction. One specific
feature of the 155 Q4 was the presence of a permanent four wheel drive system
with three differentials: a conventional unit at the front; a central epicyclic
unit that engaged directly with the gearbox layshaft incorporating an integral
Ferguson viscous coupling - and a Torsen unit at the rear.
Under normal conditions, the central distribution distributed drive torque with
a slight preference to the rear wheels. If one of the two axles lost grip
excessively compared to the other, the Ferguson coupling cut in to transfer
drive torque (up to 100%) gradually to the wheels with more grip.
The efficacy of the system was further increased by a Torsen rear differential
that acted as a self-locking unit and allowed the wheels to turn at different
This transmission configuration was combined with a particularly advanced ABS.
This technical configuration ensured that the 155 Q4 remained glued to the
ground and was easy and entertaining to drive while remaining safe in every
situation. The same attributes were displayed by the versions raced in the
German Speed Touring championship: in 1993, the 155 V6 TI saw off the
competition to triumph in the DTM with Larini at the wheel.
Alfa Romeo brought the incredible technical experience it had built up over the
years to bear when it produced a four wheel drive version of its range leader,
the 164. In December 1993, customers were able to buy a 164 Q4 powered by the
legendary 231 bhp V6 engine.
In this case, the four wheel drive layout had been further developed to ensure
maximum performance and peak driving comfort. The heart of the system was the
central Viscomatic viscous coupling developed exclusively by Alfa Romeo in
conjunction with Steyr-Puch.
The Viscomatic was managed by an on-board electronic system that communicated in
real time with the engine control unit and ABS control unit. Moment by moment,
the system detected and processed information on four different parameters:
total drive torque requested, speed, steering angle and slip difference between
front and rear axles. It was able to adjust drive torque distribution between
the axles with incredible speed on the basis of vehicle speed, cornering radius,
engine rpm, throttle opening and closure and ABS parameters. This guaranteed
improved torque distribution at any moment and in any situation.
In this case too, the Q4 drive system was based on a Torsen self-locking rear
differential. This rear differential was responsible for the important task of
redistributing the torque allocated to the rear end (in real time) between the
wheels on the rear axle: this benefited traction and also car handling over
An epicyclic unit was also fitted between the coupling and rear differential to
amplify speed differences between coupling input and output. This made it faster
and more sensitive while reducing the level of torque managed by the coupling.
Today this great Alfa Romeo tradition brings us the Alfa Crosswagon Q4 and Alfa
Sportwagon Q4, a new approach to the 4x4 world that adds a whole new meaning to
versatility and sportiness.