News Decemberr 9 2006

Alfa launches Q2 system on 147 and GT diesels at Bologna Motor Show

Alfa of course are showing off their magnificent limited edition 8C Competizione (only 500 will be built) at the show – set in a huge display case – alongside their new range. Two existing models – the 147 and GT are given a quasi AWD makeover with the new Q2 system outlined below.

Also on the stand next to the new Brera and Brera-based Spider are a 159 and Sportwagon – fitted with the new 6 speed Qtronic automatic gearbox that will be coming to Australia next year.

Here are some technical details from Alfa on the workings of the new Q2 system. At this point we do not know if these models will appear in Australia.

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Alfa GT and Alfa 147

The "Q2" system

Alfa Romeo presents the ‘Q2’ self-locking front differential, which improves all the strong points of a front-wheel drive system in terms of active safety, making driving more enjoyable and enhancing control. The innovative system provides some of the advantages typical of four-wheel drive, but at a significantly lower cost and weight.

The system is now available exclusively with the 150 bhp JTDM engine on the Alfa GT and Alfa 147, but will subsequently be extended to other models in the Alfa Romeo range. It is a step forward that reflects the excellent weight/power ratio of this unit, which benefits from Common Rail technology, but also from the leading role that diesel is now playing even in the field of racing engines. The ‘Q2’ system matches the torque and power deliveries of the 1.9 JTDM perfectly, increasing the car’s already excellent performance with a conventional differential.

Here is how it works. The main element of the ‘Q2’ system is a limited slip differential, of the Torsen mechanical type. This differential splits torque between the front drive wheels dynamically and constantly, according to driving conditions and the road surface. Combined with the exclusive double wishbone front suspension, the system allows very effective fine-tuning of the car.

Alfa Romeo started from the excellent reputation that front-wheel drive enjoys with customers (in fact it is the layout chosen by the majority of car-makers). Suffice it to say that, in addition to the overall benefits of this type of architecture (weight, roominess, etc.), in extreme conditions, the understeer typical of front-wheel drive enables the driver to respond more instinctively to the car’s reactions: this gives the impression that front-wheel drive is more ‘responsive’ than rear-wheel drive.

To highlight these benefits, Alfa Romeo has developed the ‘Q2’ system which embodies all the strengths of front-wheel drive, significantly increasing roadholding, traction and stability on the release, while attenuating understeer on acceleration, as well as the intervention of the electronic control systems and steering wheel vibration.
The two practical examples below highlight the technical potential of the ‘Q2’ system.

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Case no. 1

When the car corners

Taking a corner when grip is poor (wet road, snow, mud, etc.) or with a sporty driving style, often results in a loss of grip on the inside wheel. When the transfer of the lateral load takes weight off the suspension, torque on the inside wheel is reduced, and a conventional differential (which distributes the same amount of torque to both wheels) transfers an equal amount of torque to the outside wheel, but this is insufficient for good traction.

In this situation the car can respond in two different ways, depending on the equipment mounted. On a model without ASR-VDC, the perceived result is the slipping of the inside wheel, a loss of control (strong understeer) and a lack of acceleration coming out of the bend. If, on the other hand, the car is equipped with ASR-VDC, the driving assistance systems kick in, taking power from the engine, and acting on the throttle valve and the braking system, so that it becomes impossible to modulate the accelerator, producing the unpleasant sensation of a drop in power.

In both cases, the result is that as the car comes out of the bend, the driver has the sensation that it is ‘stationary’.

What happens when the ‘Q2’ system is present

When the inside wheel starts to lose grip, the torque is partially transferred to the outside wheel, producing less understeer and greater stability, and increasing cornering speed.

The improved mechanical efficiency of the ‘Q2’ transmission delays the intervention of the vehicle control systems, guaranteeing better traction as the car exits the bend, which makes driving more enjoyable and maintains complete control of the vehicle.

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Case no. 2

Surfaces with poor grip

On surfaces with poor grip, it is quite common for the drive wheels to have different degrees of grip. For example, grip under the two wheels could differ on snow-covered or wet roads.

In these conditions, starting off or accelerating sharply could cause the wheels to slip, generating critical friction conditions, a strong reaction on the steering wheel, and inadequate take-off, making it necessary to correct the steering-wheel continuously to maintain the trajectory.

What happens when the ‘Q2’ system is present

The negative effects are attenuated by the gradual transfer of torque to the wheel that can exploit the best friction coefficient, simplifying a hill start, for example, and making driving on all roads with changing surface conditions safer and more comfortable.

© italiancar.net 09/12/06