UK models comprise 1.8 TS 16V, 2.0 TS 16V and
2.0 TS 16V Super. Compared to the Super version,
the 1.8 TS and 2.0 TS suspension is lowered by
15mm and there are different damper settings,
different design alloy wheels and 205/50 VR low
profile tyres. UK owners could take things a stage
further with a Sports Pack, (not available on
the Super), that consists of a specially designed
rear spoiler, body-colour side skirts and black
16-inch alloy rims with 205/45 ZR tyres.
The well specified entry level 140 bhp 1.8 16V
Twin Spark was first introduced in June 1996 and
has the most powerful engine in its class.
At the heart of the new range, the 2.0 Twin Spark
16V is a true 130mph sports saloon with an all-new
Alfa Romeo engine - a cause for celebration in
itself. The 150bhp Twin Spark 2.0 16V is the sporting
heart of the 155 - the Cuore Sportivo.
A wide shouldered and muscular stance reflects
its sparkling performance (0-62mph in 9.3 secs)
and superb handling that combine with comfort,
sound ergonomic design and refinement to make
the 155 a unique driving experience.
The 155 is wider, lower and more purposeful than
its mid-1995 predecessor. Its broader track is
acknowledged by flared front and rear panels and
a modified aerodynamic profile for the wings,
spoilers and lower part of the door panels. Re-styled
flanks imbue the shape with a new sense of muscular
definition. But it’s a shape that also slips
cleanly through the air.
Its
surfaces are smooth and uncluttered, free from unnecessary
adornment. Flush handles fit snugly to the doors,
front and rear pillars are raked at the optimum
angle for aerodynamic efficiency. The new front
grille is a honeycomb design with a body-colour
surround, while the unmistakable triangular shield
set elegantly into the nose is now chrome plated.
The distinctive profile is characterised by slim
A-pillars which not only aid forward visibility
but provide a seamless, harmonious link between
roof and bonnet. The short tail and the way the
waist rises towards the rear lends a mild, but not
overstated, ‘wedge’ effect to the styling.
Light, spacious and comfortably trimmed, the cabin’s
roominess hasn’t been achieved at the expense
of the boot, which has an impressive 18.5 cu ft
volume. Naturally, comfort and quietness were priorities,
and were achieved through mechanical refinement
and effective soundproofing of the bodywork. Extensive
use has been made of sound-deadening materials with
polyurethane foam forming effective barriers against
noise intrusion as well as providing vibration damping.
Large electrically adjustable, body-colour door
mirrors mean a broader view behind, polyelliptical
headlamps a longer sight at night. And, of course,
the leather-rimmed steering wheel accommodates
an airbag.
The steering wheel and front seat belt pillar
anchorage adjust for height, while the main controls
in the new 155 - from the pedals to the gearlever
- are designed to be as direct as possible, natural
and intuitive in feel. The same ‘instinctive’
approach was applied to the design and positioning
of the column-mounted stalks which are within
easy reach of the fingertips and allow the driver
to concentrate on the driving. Likewise, the controls
sited on the centre console and door panels are
convenient and comfortable to use.
2-litre Twin Spark 16V engine
2-litre
16-valve Twin Spark unit is part of the new modular family
of engines (which also includes the very similar 1.8 litre
TS 16V unit) built at the brand-new Pratola Serra plant
(Avellino). It was designed with the aim of exploiting
modular construction for a more streamlined and efficient
production process and higher quality standards.
There is more to Alfa’s new 2.0-litre engine
than meets the eye. Even the Twin Spark business
is more subtle than you might expect. Each combustion
chamber has two spark plugs, but they are of different
sizes and have different duties. The larger one
is central and fires the compressed charge at
the beginning of the power phase; the smaller,
off at one end of the chamber, sparks 180 degrees
later at the end of the exhaust phase, protecting
the catalytic converter by ensuring that no unburnt
fuel should reach it. Since each cylinder has
its own direct-ignition coil, the plug leads are
arrayed so that the divided output from each coil
is directed to two different cylinders.
Architecturally it is a classic engine, with four
cylinders in line beneath a head featuring two camshafts
controlling four valves inclined into each combustion
chamber. Go into detail, though, and you find that
what looks superficially traditional is actually
modern and innovative.
Those two overhead camshafts, for instance, can
have their relative timing altered so as to vary
the amount of overlap between the exhaust and intake
events. Alfa Romeo has done this before, but the
latest electronic engine-management system now applies
a more subtle logic to the control of the variable
valve timing. The phase shift is actually less than
in the past (a matter of 25 degrees instead of 30),
but it moves to give full overlap at as little as
1800 rpm when maximum torque is wanted, and to eliminate
overlap either at full power or at idling. By this
means, in conjunction with the precise metering
of fuel and timing of ignition that are part of
the responsibilities of the electronics (along with
modulating knock, monitoring emissions, and governing
the exhaust gas recirculation system), this new
engine reaches a brake mean effective pressure -
the only true measure of how efficiently an engine
breathes and burns its air and fuel - of 172.5 lb
ft/sq in. That is a respectable figure, very respectable
when one appreciates that this is not an engine
designed to give a peaky power delivery. On the
contrary, it maintains at least 90 per cent of its
maximum torque with wide-open throttle throughout
the speed band from as low as 2500 to as high as
6200 rpm.
In other words, it pulls very strongly all the way.
It will tolerate full throttle at as little as 1500
rpm and give rewarding results at the other end
of the tachometer scale where the needle is into
the red at 7000.
The new engine has numerous technical highlights:
- Hydraulic tappets (with drain-proof circuits to
prevent knock) do away with the need for periodic
valve clearance adjustment.
- Staged, sequential static ignition system uses
two platinum spark plugs of different sizes per
cylinder, arranged asymmetrically and designed to
last for 62,000 miles. Twin coils are built into
the cylinder head.
The
latest generation integrated management system,
Bosch Motronic M2. 10.3, not only controls the ignition
and sequential indirect injection system but also
modulates the variable valve timing operation, controls
knock by adjusting advance separately for each cylinder
and governs the exhaust gas recirculation system
(EGR) built into the cylinder head. The knock control
system is active and selective for each cylinder.
It achieves peak performance for minimum specific
fuel consumption by keeping the ignition advance
close to knock level without actually allowing knock
to take place.
- Two contra-rotating shafts balance out alternating
moving masses. In conjunction with a crankshaft
sporting eight counterweights and a torsional vibration
damper, and a cast aluminium alloy oil sump design
that stiffens the engine/gearbox assembly by having
six securing points instead of the usual four, the
balancer shafts reduce vibration and noise to typical
six cylinder levels.
- A heated throttle body with electromechanical
idle actuator ensures prompt engine responses and
smooth power delivery.
- A water/oil heat exchanger keeps lubricant properties
constant even if the engine is used for long periods
at maximum RPM.
- Automatic tensioners for timing, balancer shafts
and accessory drive belts are maintenance-free until
at least 62,000 miles.
- A three-way catalytic converter with ceramic
core and Lambda probe further reduce the already
low emission levels achieved through optimisation
of combustion parameters.
- A stainless steel exhaust manifold with low
thermal inertia helps keep fuel consumption low
on short trips by minimising the time required
for the catalytic converter to heat up. This reduces
harmful emissions and extends catalyst life.
- Peak power is 150bhp-EC (110 kW-EC) at 6200rpm
with 138lb ft of torque (186 Nm-EC) at 4000rpm.
Between 2500 and 6200rpm, available torque exceeds
90 per cent of the maximum. This gives a high
specific output of 76bhp per litre and a power/weight
ratio of 115bhp/tonne. The engine meets EC phase
2 emissions standards.
Mechanics
Notably
high-geared rack and pinion steering (just 2.1 turns between
locks on the 1.8 and 2.0 litre TS 16V) is hydraulically
assisted and is a fine match for MacPherson strut suspension
designed from the outset to match the high power of the
engines. The chassis strikes an intelligent balance between
finely-honed handling and pliant ride comfort. Wheel movements
generous enough to deal with a wide variety of road surfaces
thanks to the long travel suspension, are closely controlled
by precisely calculated spring and damper rates. In addition,
the trailing arm rear suspension is designed to provide
maximum directional stability, keeping the wheels parallel
to the axis of the vehicles at all times. A smooth, quick
and positive gear change and well cushioned clutch help
minimise driver fatigue.
The disc brakes used all-round are large and ventilated
at the front to dissipate heat more quickly. The aim isn’t
merely powerful, progressive braking but peak efficiency
maintained over prolonged periods of hard use. The vacuum
servo modulates pedal pressure accurately, taking the
effort out of braking but not the feel. A pressure limiting
valve at the rear prevents premature rear-wheel lock-up
and effectively ‘normalises’ pedal sensitivity
during heavy braking. ABS anti-lock braking controlled
by microprocessor technology is standard equipment.
Alfa Romeos are renowned for their high levels
of active and passive safety. Performance goes
hand in hand with responsibility and attention
to detail. The 155’s cabin ergonomics, for
example, ensure that the driver is comfortable
but alert. The car’s passive safety features
are the result of extensive computer aided design
work. Energy-absorbing crumple zones surround
the passenger compartment, which is designed to
remain intact and protect occupants during a collision.
Seat belts have pre-tensioners and are height
adjustable, and all the seats have head restraints
to minimise the risk of neck injuries. There are
no jutting edges on the facia which could cause
injury in a crash, and the steering column is
of the collapsible safety type with a driver’s
airbag standard equipment across the range.
Part
of the comprehensive standard security equipment
for all 155s is the Alfa CODE electronic key. It
has etched external teeth, a microprocessor/transponder
printed in the top and thwarts attempts to steal
the car by disabling the ignition, short-circuiting
leads and changing electrical paths. All 155 versions
are also fitted with an alarm as standard equipment.
The 155 range is offered with a comprehensive
warranty package including an 8-year corrosion
protection warranty, a 3-year paint warranty and
a 3-year/60,000 mile mechanical warranty.
