High-powered diesel versions of Alfa Romeo’s multi-award winning Alfa 147 and Alfa GT models now feature a sporty twist, in the form of a limited slip front differential that further improves and increases driving enjoyment and control.

The system is available exclusively with the 150bhp JTDM engine in the Alfa GT and Alfa 147.

Drivers choosing this option will benefit from a more sensitive set-up that maintains traction, road-holding and stability during hard acceleration in low grip conditions, and notably when exiting corners.

Up front, Alfa Romeo’s new Q2 limited slip differential splits torque between the two front wheels constantly and dynamically in response to changing driving conditions and road surfaces; ensuring that effective grip is maintained at all times.

Whilst not the first manufacturer to employ an LSD installation at the front of the vehicle, Alfa Romeo has combined the technology with an exclusive double wishbone front suspension to allow very effective fine tuning of the car’s chassis. In addition, Alfa Romeo has lowered the ride height, and specified different anti-roll bars, springs and dampers, along with bigger wheels with low-profile tyres.

Perhaps the most seductive advantage of Alfa’s Q2 system is that it works with the traction control to maintain power and acceleration at all times. Without the Q2 arrangement in place, all traction control systems will reduce power to a spinning wheel to allow the car to regain grip – effectively slowing the car down. With Q2, it simply shifts the power to the wheel with more grip, and therefore maintains acceleration.

To help differentiate these Q2 models from their stablemates, both the Alfa 147 and Alfa GT models boast a number of exterior and interior stylistic changes.

Outside, these include a satin finish on the ‘whiskers’, grille and mirror housings plus special 17" alloys on the 147 – 18" on the GT – a rear spoiler, chromed exhaust, lowered suspension and a Q2 boot badge.

The sporty theme continues inside with red dials and white lighting, plus leather upholstery and red stitching on the steering wheel, gear lever and handbrake gaiter. Other neat touches include grey anthracite trims on the steering wheel spokes and console, and special Q2 kick plates and aluminium pedals.

One further enhancement is the fitment of steering wheel mounted controls for the Bose stereo, cruise control and the VDC system.

Alfa Romeo UK Marketing Director, Nicholas Bernard, says: "These Alfa 147 and Alfa GT models bring a new level of driving enjoyment to the range. Q2 will excite motorists who really love to drive their cars. In short, the innovative system provides many of the advantages typical of four-wheel drive, but at a significantly lower cost and weight."

ALFA ROMEO Q2 RANGE PRICE LIST

3-dr 147 Sport Limited Edition 1.9 JTDM 16V: £16,950

5-dr 147 Sport Limited Edition 1.9 JTDM 16V: £17,450

GT Blackline Limited Edition 1.9 JTDM 16V: £21,430

BENEFITS OF Q2 IN REAL WORLD DRIVING

Alfa Romeo’s Q2 system embodies all the strengths of front-wheel drive, while significantly increasing roadholding, traction and stability on the over-run and attenuating understeer on acceleration, delaying the intervention of the electronic control systems, and reducing steering wheel vibration.

Two practical examples below highlight the technical potential of the Q2 system.

When the car corners

Taking a corner when grip is poor (wet road, snow, mud, etc.) or with a sporty driving style, grip can be lost 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 splits the same torque value between 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 fitted. On a model without ASR-VDC, the perceived result is the slipping of the inside wheel, a loss of control of the car (strong understeer) and a loss of acceleration coming out of the bend. If, on the other hand, the car is equipped with ASR-VDC, the intervention of the driving assistance systems takes power from the engine, 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 feeling that it is ‘stationary’.

And with the Q2 system in place?

When the inside wheel starts to lose grip, torque is partially transferred to the outside wheel, producing less understeer, 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 while maintaining complete control of the vehicle.

Surfaces with poor grip

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

In these conditions, starting off or accelerating sharply can 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.

And with the Q2 system present?

These 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.