26th October 2002

new models: Alfa Romeo 147 GTA

>>> engine & transmission
>>> suspension

Alfa Romeo 147 GTA

>>> engine & transmission

The Alfa 147 GTA power unit is the same 3.2 V6 24 valve engine fitted to the Alfa 156 and Alfa Sportwagon GTA. It is a spirited, well-rounded engine as befits a six-cylinder unit and is derived from the now classic three-litre V6 24 valve unit fitted to top of the range Alfa 166 and GTV models. 

The Alfa 147 GTA engine differs from its predecessor in certain respects. First and foremost, power has been increased by making radical mechanical changes. The power could have been increased by adjusting the timing, fuel system and electronics. But instead the engineers have changed the crankshaft and pistons on the GTA to increase the cylinder capacity to 3.2 litres and lengthened the stroke to 78 millimetres. This was done with one very specific aim: to ensure absolute performance and high power and torque peaks combined with smooth, gradual delivery from low speeds. For this reason, the 3.2 V6 24v unit can deliver excellent performance - and that means a top speed of 246 km/h and 0 to 100 km/h in 6.3 seconds - but can also be used as an everyday car. The self-confessed goal of the GTA is this: to offer sensations unique to a racing car yet still be perfectly serviceable for everyday use. 

The 3.2 V6 24v unit fitted to the Alfa 147 GTA develops 250 bhp at 6200 rpm with a maximum torque of 300 kgm ( 30.6 kgm ) at 4800 rpm. These figures are all it takes to achieve exciting performances and are complemented by a torque curve that permits high values at low speeds. The car can also travel in sixth gear at less than 2000 rpm and unleash speed spurts without changing gear.

The increased cylinder capacity naturally required further changes. For example, the control unit software has been rewritten, the cooling system has been upgraded with the addition of an engine oil radiator - and the intake and exhaust ports have been tuned by applying a new timing pattern. 

The transmission has also been reinforced: the driveshafts are new, while the clutch is bigger and the six-speed gearbox offers new, sturdier components. The current manual gearbox will be joined next year by a Selespeed version. Developed by Magneti Marelli, this sophisticated device has a Formula 1-style operating system that makes for swifter gear shifts at both low and high speeds. The 3.2 V6 24 valve unit fitted on the Alfa 147 GTA already meets the tough Euro 4 emission limits.

>>> technical specification

Alfa Romeo 147 GTA

>>> suspension

The Alfa 147 GTA suspension layout is based on a combination of high double wishbones at the front ( the only car in its segment to offer this configuration ) and an advanced MacPherson arrangement at the rear. This engineering option has already brought the Alfa 147 great success and has been specially adapted to the upgraded features of the new car to assure the Alfa 147 GTA outstanding dynamic performance coupled with superlative comfort. 

The suspension is the final outcome of a long and thorough development process carried out on the basic layout with the aim of achieving the highest levels of driveability and handling. These features allow the person behind the wheel maximum mastery of the new car's great sports performance for the best possible results on the road. From the customer's viewpoint, the new version: 

- is responsive; 
- is smooth and accurate in its steering; 
- is very stable and easy to control even when close to the grip limit; 
- features highly contained body movements; 
- and offers great comfort in all service and road surface conditions. 

front suspension

The Alfa 147 GTA offers its drivers the great control typical of front wheel drive cars plus outstanding sportiness and driving precision. This is particularly evident over mixed routes. The credit for this goes first and foremost to the high double wishbone front suspension. The new front suspension was developed specifically for the model by the Fiat Research Centre and Alfa Romeo Research. It departs from the configuration used on the Alfa 147 in offering a reinforced lower beam, lower ride, new shock absorber and spring settings, a special wheel strut that is fastened to the steering link in a different position - and a larger diameter stabiliser bar.

These engineering improvements increase the dynamic performance of the high double wishbone suspension - known as a quadrilateral suspension because the arms ( two overlapping triangles with their bases hinged to the car body and their tips to the wheel unit ) create a four-sided figure. 

The device structure consists of a cast iron lower arm, a steel strut and an upper light alloy arm. The coaxial spring-shock absorber unit is connected to the body via a flexible mount and to the lower arm via a light alloy fork. For reasons of space and structural stiffness, the upper arm is jointed to an aluminium shell ( anchored to the body ) which acts as a support to the upper spring-shock absorber attachment. From a dynamic viewpoint, the high double wishbone layout ideally combines broad wheel travel with outstanding control of tyre service conditions. This is achieved because the upper arm is located higher than the wheel centre: this means that the area between wheel and power unit accessories can be exploited to the full. And more. Other benefits of this configuration include excellent tyre grip, improved traction even under extreme conditions, a self-alignment effect proportional to the side acceleration applied on a bend, greater steering precision and sensitivity, gradual and even steering wheel effort to the grip limit - and also cancelling of lift (lifting of the front during acceleration ) and antidive effect ( dipping of the front end when braking ).

Great attention has also been devoted to the absorption of minor roughness. Hence the choice of fluid dynamic bushes to hinge the upper triangle to the shell; split gaskets and bushes in Teflon loaded with fibreglass for the shock absorber stems - plus a Teflon seal for the shock absorber piston. 

rear suspension

The rear suspension has also undergone many technical improvements. The geometry and the constructional details of the tried and tested MacPherson configuration have both been revised. The outcome is a different body attachment position; special spring setting; different shock absorber and bush stiffness; antiroll bar with bigger diameter. 

The GTA's MacPherson suspension also adopts innovative construction features. For example, the coil springs not only offer a different stiffness and lower ride to those of the Alfa 147 but also rest on a lower and upper plate with an interposed rubber ring to reduce noise levels. And a stabiliser bar ( connected directly to the shock absorber via plastic connecting rods and jointed on steel ball joints ) with a Cellasto upper end travel block ( closed cell polyurethane that maintains its flexible properties over time ). The double-acting hydraulic shock-absorbers, also new, are pressurised and built in high strength steel with reduced thickness. Lastly, the side levers, suspension arm and rear beam bushes are all made especially for the Alfa 147 GTA. The upper shock absorber attachment also displays a new tapered block fastening system. Assembly is easier and the system is more reliable because the attachment need not be bolted to the body.

These significant technical innovations and features are bound to improve performance and driving comfort still further. Suffice it to say that the modified rear suspension can absorb obstacles more easily because the wheels withdraw lengthways to keep the car on its trajectory. The system also assures maximum directional stability when the car meets obstacles such as tram lines, dilation joints on motorway bridges. And more. The Alfa 147 GTA rear suspension increases the smoothness and alacrity of steering response and means the car is more able to align itself automatically, even under extreme conditions. This is achieved by ensuring the wheel steers consistently under side load. Not to mention the fact that the Alfa 147 GTA gains negative wheel camber during roll due to the new rear suspension. In other words, cornering grip is increased to ensure the roll centre position is more accurate to improve the car's general balance. 

Alfa Romeo 147 GTA

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