Longstones in Bridgwater, Somerset. Authorised Alfa Romeo dealership

Alfa 159

Q4 Four Wheel Drive Differential

Safer Sportiness

Alfa Romeo's permanently engaged 'Q4' traction control system creates a sure-footed drive without taking the pleasure away from the Alfa Romeo driving experience.

The control centre of this system means that "all four wheels are driven by Q4"; a Twin Differential mechanism, evolved from Torsen C.

The traction control operates permanently, shifting traction between the front and rear wheels. A maximum 57% torque can be driven to the rear wheels with a self-locking Twin Differential that manages the engine power transfer, leaving 43% traction through to the front wheels. This enables optimum handling in 'dry, neutral conditions', creating a rear-wheel drive sensation.

However, road and weather conditions change, so it's reassuring to know that this system automatically monitors wheel traction, shifting the power between front and rear, helping to match the right amount of power to each wheel for the road conditions, giving the driver a controlled, yet sporty drive.

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