Q4 logo on the rear of the Crosswagon Q4 pays due homage to the Alfa 155 and 164
Q4 cars that represented the state-of-the-art in terms of advanced sportiness
for Alfa Romeo in the Nineties.
Like those glorious cars, the transmission on the new model also features 4
permanently engaged drive wheels, three differentials and torque distribution
preferentially to the rear.
The Torsen C differential continuously modulates torque distribution between
front and rear axles according to grip. This feature makes for a sporty drive
that in turn increases active safety.
Mechanical modulation is continuous and progressive. It conveys an optimum
driving sensation that is satisfying and easy for the driver. Torque
distribution takes place without any time lag.
The car's grip performance adapts gradually in linear fashion to changing road
conditions. This mechanical system is complemented by an electronic system for
extra performance and safety margins in line with the Alfa Romeo philosophy. The
Crosswagon Q4 is absolutely cutting edge in its engineering and offers
The first of
these concerns ride comfort. The increased ground clearance and generous tyre
size brings a decided improvement when driving over obstacles while the stiffer
body helps improve the acoustic and vibrational qualities. Because not all the
torque needs be transmitted through the front axle, it has been possible to
configure the geometry of the double wishbone front suspension for ride comfort.
The Q4's four
wheel drive with Torsen C self-locking differential makes it possible to achieve
improved roadholding, driving satisfaction and smooth responses. Other
engineering configurations with electronically controlled couplings do not
confer the optimum balance between oversteer and understeer and smooth
performance achieved on the Crosswagon Q4, which translate into great active
distribution to the rear axle also adds to driving satisfaction because it makes
the car easier to handle while ensuring maximum stability when the car suddenly
veers at top speed on the motorway, as can happen during emergency manoeuvres.
performance is also better than expected. The driver need no longer fear
transmission lag and the combination of electronic and mechanical control makes
differential locking effective in extreme conditions. For example, the vehicle
can easily overcome tricky obstacles that may cause the car to twist with one
wheel completely off the ground.
The Crosswagon Q4 is four wheel drive Alfa Romeo style: an essentially
mechanical system complemented by the most advanced electronics to assure
maximum driving comfort together with optimum performance and total safety. For
these reasons, the Alfa Crosswagon Q4 is unique in the 4x4 scenario.
Driving satisfaction is always a strength of Alfa Romeo cars and the Crosswagon
Q4 is no exception. The model reprises the layout adopted on the 156 with some
adjustment: high double-wishbone suspension that optimises the area of contact
between tyre and ground; MacPherson rear suspension with transverse rods of
different lengths for unique stability and handling.
The earlier version has been redesigned and optimised due to the car's higher
ground clearance compared to the basic model while also maintaining the steering
feel and precision typical of an on-road Alfa 156. The rear suspension has been
revised to increase car stability during pull-in, release and braking to adapt
to four wheel drive performance.
In detail, the choice of a double wishbone layout for the front suspension meets
a specific aim: to achieve maximum lateral hold, a highly effective and precise
steering response and excellent traction - and to wed these specifications with
an ability to absorb and dampen road surface roughness typical of the most
comfortable cars in the segment. The double wishbone layout allows high
longitudinal flexibility to be achieved on the wheel side without impairing
roadholding on corners and steering dynamics.
The car's on-road behaviour is aided by a rear suspension that gives the model
the greatest stability in high speed manoeuvres and all the agility required of
a true sports car over tight mixed routes. Hence the choice of a MacPherson
suspension featuring asymmetrical arms and refined elastokinetic properties. On
the Crosswagon Q4, the rear suspension is connected to the chassis by a
crossmember made out of vacuum cast aluminium. The benefits of the MacPherson
strut layout include low weight, great comfort (assured by extensive wheel
travels and longitudinal flexibility) and numerous ride control options.
The front and rear suspension layout also allows the various joints, including
the steering arm joints, to yield in a calibrated manner without this affecting
driving precision. The set of features adopted allowed us to achieve the very
best results because we have succeeded in insulating out all noise and absorbing
the minor roughness that often causes annoying knocking sounds to reverberate
from the body.
Power unit: 110 kW (150 bhp) 1.9 JTD 16v M-Jet
At the end of 2002, Alfa Romeo introduced its 140 bhp 1.9 16v M-Jet, the first
of the second generation of Common Rail engines in the world. The engine was
adopted on the Alfa 147, 156 and Sportwagon with a sporty six-speed manual
gearbox and has now been further developed for the Alfa GT, offering a power
output of 150 bhp. And this very engine will also be used on the new Crosswagon
Q4: a 4 cylinder in line engine with a bore of 82 millimetres and stroke of 90.4
mm, capable of delivering a power output of 110 kW at 4000 rpm and a torque of
305 Nm (31 kgm) at 2000 rpm.
The new turbodiesel has undergone several engineering changes to increase
performance and engine torque at low speeds and to reduce noise and vibration
levels. For example, the Common Rail system used on the 1.9 JTD 16v M-Jet
includes two new strategies for automatically calibrating and balancing the
diesel injected to lower noise and reduce vibration.
It goes without saying that the Alfa Crosswagon Q4 guarantees extremely
attractive performance figures: the top speed is 192 km/h and acceleration from
0 - 100 km/h takes place in 10.5 seconds.
All this comes with very frugal fuel consumption, the new all-terrain sports
- 9.3 l/100 km over an urban
- 5.8 l/100 km over an extra
- 7.1 l/100 km over a combined
The Multijet system, secret of
second generation JTD engines.
principles of second generation turbodiesel engines remain the same, i.e. high
injection pressure and electronic injector control. But one extra feature has
been added: during each engine cycle, the number of injections increases over
and above the current number of two. In this way, the same amount of diesel is
burnt inside the cylinder but in several portions to achieve smoother
The advantages include lower running noise, reduced emissions and a 6-7%
increase in performance. All this comes with a level of engine efficiency that
improves car handling still further.
These results are not to be underestimated, particularly because they are
obtained with an engine that represents an incredible leap forward from
prechamber diesels and even improves on first generation JTD engines. The secret
of the Multijet engine lies in the control unit that governs the electric
injector opening and closure system (and also in the injectors themselves). The
crucial element is the electronic control unit itself that can perform a set of
injections that may be very closely spaced.
Fiat Auto's researchers developed the part (together with the injectors)
especially for this application. It is designed to deliver the multiple
injections that assure the designer more accurate control of pressures and
temperatures developed inside the combustion chamber and also more efficient use
of air taken into the cylinders.
This enables further goals to be achieved: quieter combustion, reduced emissions
and increased performance. The Multijet system is underpinned by long years of
research. Our engineers began by resolving the problem of limits imposed by the
control units. Then they went on to map the benefits they could achieve by
plotting different multiple injection sequences (two secondary injections very
close to the main injection; one secondary injection not too close to the main
injection plus two closely-spaced secondary injections; one secondary injection
and then two main injections close together after a certain period etc.) against
different engine service conditions: in the idling region; with low loads and
low rpm; with high rpm and moderate load; with low rpm and high load etc.
The study revealed the potential of the system and showed that great benefits
are achievable in all cases, though these tend to focus on one field or another
according to the type of sequence chosen and the engine service area targeted.
In some cases, for example, the priority is to reduce start-up times and fume
levels, in other cases it is to increase torque and reduce noise while in others
it is to reduce emissions and ensure a quieter drive.
And this hard work has led to the creation of the Multijet engines: another
first for the Fiat Group in the diesel engine field. But we had been putting in
a lot of hard work behind the scenes since 1986, the date that marked the
arrival of the Croma TDI, the first direct injection diesel vehicle in the
At that time, this represented a true engineering breakthrough that was later
adopted by other manufacturers. Direct diesel injection engines offered better
performance and lower fuel consumption but failed to resolve the problem of
excessive engine noise at low rpms and while speeding up or slowing down. So
work began on a more advanced direct injection system and a few years later this
led to the development of the Common Rail principle and the Unijet system.
The idea first came from the Zurich University research laboratories where
scientists were working on an injection system that had never before been
applied to a vehicle, i.e. the Common Rail system. The idea is simple yet
revolutionary. If you continue to push diesel into a tank, the pressure inside
will rise and the tank itself will become a hydraulic accumulator (or rail),
i.e. a reserve of pressurised fuel ready for use.
Three years later, in 1990, the Unijet system developed by Magneti Marelli, Fiat
Research Centre and Elasis on the Common Rail principle entered the
pre-production stage. This stage was complete in 1994, when Fiat Auto started to
look for a partner with superlative knowledge of diesel engine injection
systems. The final stage of the project, i.e. completion of development and
industrial production, was eventually entrusted to Robert Bosch.
Now our story has reached 1997 and the launch date of the Alfa 156 JTD with its
revolutionary turbodiesel engine. Compared to conventional diesel power units,
the JTD guarantees an average improvement in performance of 12% together with a
15% reduction in fuel consumption. These results meant that cars fitted with the
engine were an immediate hit.
Now the time is ripe for the second generation of JTD engines, the Multijet and
multivalve units: in 2002 with the 1.9 M-Jet 16v (forerunner of this new family
of multipoint injection engines) in 2003 with the 1.9 upgraded to 150 bhp for
the Alfa GT and the 129 kW (175 bhp) 2.4 JTD Multijet 20v available on Alfa 166,
Alfa 156 and Sportwagon models. Now comes the turn of the Crosswagon Q4 to enjoy
all the benefits of the 150 bhp 1.9 JTD 16v M-Jet.