Alfa Spider's central differential is a Torsen C that encloses the front differential for the first time, a solution that ensures considerable benefits in terms of dimensions, weights and also performance. It exploits the forces set up by the front differential to increase its locking effect (35% during traction and 45% during release) to set up a certain self-locking effect on the front differential as well (up to 20%). The consequence of this is improved traction and cornering stability.

The basic torque distribution of the Q4 system is mainly to the rear (43/57) for greater sportiness. Due to its locking effect, the central differential is able to send drive torque to the axle with the best grip on the ground moment by moment. This allows the system to switch from the initial torque distribution pattern to a distribution pattern focused on the front (72/28) or a distribution focused on the rear (22/78) in a fast, automatic and continuous manner according to the grip and slip levels of all four wheels.

The Alfa Romeo Q4 four wheel drive system implements permanent, dynamic torque distribution over all four wheels to achieve the highest levels of active safety. The Q4 system is four wheel drive, Alfa Romeo style: an essentially mechanical system complemented by the most advanced electronics to assure maximum driving comfort together with optimum performance and total safety.

The vehicle is absolutely cutting edge as far as engineering is concerned and offers significant benefits:
- The Q4's four wheel drive with advanced Torsen C self-locking differential (Twin Diff.) makes it possible to achieve improved roadholding, driving satisfaction and smooth responses.
- Preferential distribution to the rear axle also adds to the driving satisfaction because it makes the car easier to handle while ensuring maximum stability when the car suddenly veers at top speed on the motorway, as can happen during emergency manoeuvres.
- The ability to travel safely in poor grip conditions without the aid of electronics in torque split for constant driving satisfaction.




The most sophisticated engineering at the service of safety

As far as safety is concerned, the Alfa Spider offers the most sophisticated electronic devices to control the vehicle's dynamic performance (from braking to traction) and push its dynamic limits still further. These devices are not intrusive for the driver but greatly benefit safety. These devices have been developed operationally through simulations and meticulous track testing with the aim of ensuring maximum driving satisfaction.


Braking system

The power-assisted, hydraulic system comprises two cross-over independent circuits, and is particularly effective, guaranteeing prompt, smooth braking combined with minimal stopping distances. The system naturally differs according to the engine version (in terms of weight and power): vehicles equipped with the 2.2 JTS are fitted with 305 mm self-ventilated discs on the front wheels and cast iron floating calliper with piston; the rear brake discs are solid (278 mm diameter) while the calliper is aluminium with a piston.

The powerful Alfa Spider 3.2 V6 Q4 is fitted with 330 mm ventilated discs with a four piston monobloc aluminium calliper on the front wheels; a 292 mm disc, also ventilated, with a floating calliper on the rear wheels.

This vehicle marks the first application of a monobloc aluminium calliper with radial attachments to the front brakes of an Alfa Romeo: this option increases calliper stiffness without increasing the weight and therefore makes for increased performance, particularly during a sporty drive.


ABS with EBD

In addition to a high-performing brake system, the Alfa Spider also comes with one of the most advanced ABS antilock brake systems on the market today. It features four active sensors and a hydraulic control unit with 12 solenoids. The ABS contains an electronic brakeforce distributor (EBD).

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