Last week, a Garnet Red Audi Q5 (second-gen SUV reaching Malaysia in Q3 this year) born at the San José Chiapa plant in Mexico became the eight millionth Audi vehicle to benefit from the brand’s famous quattro all-wheel-drive system, which has been successful in motorsport as well as on the road. “Audi is quattro and quattro is Audi,” was how the press release announcing the milestone started.

The Vorsprung durch Technik brand has been peddling quattro cars for over 35 years now, the tech having made its debut in 1980 where AWD was not common. Today, quattro is standard in the Audi Q7 SUV, the Audi A4 and A6 allroad, the A8 limo, the R8 and all S and RS models. In all other models, AWD is available as an option.

It’s a popular choice too – in 2015, 44% of Audi customers worldwide chose models with quattro drive. The Audi Q5 topped the list with about 262,000 units. The quattro models generated particularly strong sales in the US, Canada, Russia and the Middle East. In Germany quattro sales totaled 122,048 cars.

The tech premiered in 1980 in the Ur-quattro. In 1986, Audi replaced the first-gen’s manually locking centre differential with a Torsen diff that could variably distribute drive torque. The planetary drive followed in 2005, with its asymmetrical, dynamic distribution of power and torque. The self-locking centre diff is continuously being developed by Ingolstadt.

Today, Audi offers quattro in different versions tailored to each model. For compact cars with transverse-mounted engines, an electronically controlled hydraulic multi-plate clutch is mounted at the rear axle. On the R8 mid-engine sports car, the multi-plate clutch is mounted on the front axle. These active systems distribute drive variably to both axles according to the driving situations.

The self-locking centre diff used in many Audi models with a longitudinally installed, front-mounted engine, is a purely mechanical planetary gear. Normally it splits the drive torque sent to the front and rear wheels with a 40:60 distribution.

The sport differential is available on the rear axle with some of the top engines. It actively distributes torque between the rear wheels by means of two superposition units, each with an electrohydraulic multi-plate clutch. In extreme cases, almost all available torque is sent to one wheel – the system actually pushes the car into the curve, eliminating understeer.

The latest development from Audi is the quattro system featuring ultra technology. Designed for models with a longitudinally mounted engine, it uses an actively controlled multi-plate clutch at the end of the transmission which distributes the torque variably between the drive axles in AWD operation.

A decoupler in the rear axle differential can additionally open the connection to the rear wheels. Both clutches are opened in driving situations where AWD doesn’t offer any advantage. This way, the parts of the rear drivetrain responsible for drag are not engaged.

The system’s control unit uses a multitude of data to produce a model of the vehicle’s status projecting about half a second into the future. If the system detects, for instance, that the inside wheel is about to lose grip, it switches predictively to AWD. As a result, quattro is always ready when it is needed. Audi says that the new concept considerably boosts efficiency without sacrificing traction or driving dynamics.