Audi’s Quattro is probably one of the car industry’s most famous four wheel drive system, but this name represents more than just an all-wheel drive system, because during its existence of more than 30 years, some great things were connected to this name. So let’s take a look back in history and see how this system became so famous and important for the German car manufacturer.
The system was introduced for the first time in 1980 and has been constantly evolving ever since. Today, Audi is offering four different quattro technologies, each one designed for a specific type of vehicle.
It all started with the Volkswagen Typ 183 military vehicle, also known as the Volkswagen Iltis (German for “polecat”). The Iltis was an off-road vehicle built by Volkswagen for the German military. It was based on an upgrade version of the famous Munga’s platform, it was powered by a four cylinder 1.7-liter Audi engine that produced 75 hp and featured a new four wheel drive system created from components from the Audi 100. This system was going to be the starting point for the upcoming “quattro” technology. The Iltis passed all government tests and was chosen over the Mercedes-Benz’s G Class, which was a capable model but a lot more expensive than the Iltis. A total number of 9,547 units were built between 1978 and 1988, 8,800 of which went to the German military and the rest (747 units) went to the Canadian Forces and Estonian Army.
Using the four wheel drive system developed for the Volkswagen Iltis, a small team of Audi engineers thought it would be an interesting idea to use this technology on a small street coupe. The initial purpose was to get the car homologated for the WRC (World Rally Championship). When working on the new system, Audi’s engineers stripped the separate heavy transfer case and the additional front driveshaft. This was the conventional way four wheel drive systems were built, but it wasn’t what Audi needed for their upcoming sports car. So the new technology basically became the world’s first light four wheel drive system that could be used for other things than off-roading.
One brilliant idea Audi’s engineers came up with and which made this system so good was a hollow 263 mm driveshaft which was able to transmit power in two directions, the rear part going into the central differential. Through this type of driveshaft, 50 percent of the power was permanently sent to the rear axle, in any condition and at any time. The other half of the power was sent to the front axle through a separate axle that was rotating inside the hollow driveshaft.
The name chosen for the new car was Audi Quattro and it made its debut at the 1980 Geneva Motor Show. The Audi Quattro quickly became a star of its times, thanks to its permanent all-wheel drive system, light and compact structure, while its racing DNA seduced sports cars fans all over the world. One important difference Audi was also keen on emphasizing was the naming: “quattro” is the name of their all-wheel drive system, while “Quattro” is the name of the original car.
And the place where the Audi Quattro really showed what it was capable of was motorsport, especially rally racing. In 1981, only one year after entering racing, the Audi Quattro won the first rally, with Michele Mouton winning the 1981 Sanremo Rally (she also became the first woman to achieve a world championship rally win). In 1982, even though the world rally champion didn’t drive the Quattro, Audi won the manufacturers’ championship. Driving an Audi Quattro, Hannu Mikola won the championship in 1983 and Stig Blomqvist followed him a year later, in 1984. Another important driver who won rallys at the wheel of a Quattro was the legendary Walter Rohl. The car was also successful in other competitions, such as the Pikes Peak International Hill Climb which it won six times in a row: John Buffum (1982 and 1983), Michele Mouton (1984 and 1985),Bobby Unser (1986) and Walter Rohl in 1987. The success in motorsport also made the car very popular among car enthusiasts, with 11,452 units sold between 1980 and 1991.
Starting with the 1980s, the German carmaker would implement the new four wheel drive system on many of its models, always upgrading it and giving it new and improved elements, which were or later became very popular in the car industry.
The debut of the Audi 80 in 1986 also marked the debut of a new central differential. This type of limited-slip differential, called Torsen, was invented by American Vernon Gleasman and its name stands for Torque Sensing. It was capable of sending torque at a ratio of 50:50 to both front and rear axles, but if need, it could automatically adjust this ratio and send 75% of the torque to the axle with the better traction. The differential would lock only when under load and would immediately unlock when the driver eased on the gas pedal. Also, to benefit from better traction when starting the car in extreme conditions, the driver was able to lock the rear differential through an electro-hydraulic system that was activated by pushing a button on the dashboard.
This technology has been used by Audi on almost all models in its lineup, except for the A3/S3 and TT and it was also adopted by several other car manufacturers such as Volkswagen (whose four wheel drive system is badged “4motion”), Chevrolet (on the TrailBlazer SS), Lexus (GX, LS 600h, LX), Saab 9-7X Aero, Range Rover (L322), Nissan (Frontier) and Toyota (Landcruiser, FJ Cruiser and 4runner).
Hydraulic Multi-Plate Clutch
The Torsen differential was an excellent solution for cars that used a longitudinal engine configuration), but something else had to be developed for more compact models that featured a transverse-mounted engine (such as the A3/S3 and TT mentioned above). And Audi’s engineers’ response came in the form of a multi-plate clutch that was controlled both electronically and hydraulically. The system was first introduced in 1998 on the Audi TT quattro and the Audi A3 quattro.
This multi-plate clutch features a clutch positioned at the rear end of the drive shaft, in front of the rear differential. When driving in normal conditions, all the torque is sent to the front axle, but the electronic controller analyzes a large variety of data to determine road conditions and adjust power transfer depending on necessities.
Self-Locking Center Differential
In 2005, Audi went to the next level in upgrading the quattro system, when the second generation of the high-performance RS4 was launched. The new self-locking central differential was an entirely mechanic device (no electronics involved) and it is still being used on almost all models with a longitudinal mounted engine. During normal driving conditions, the central differential sends 40% of torque to the front axle and 60% to the rear axle. However, if needed, the system can reverse this ratio and send 60% to the front wheels and 40% to the rear, or as much as 80% to the rear axle. The Audi Q7 SUV uses a special version of this differential which is integrated in the transfer case.
The high-performance sports car Audi R8 has a special place in the German car manufacturer’s lineup and not only because it’s a beautiful and capable sports car, but because it also has a structure that is quite different from what we usually see on similar models. The engine is centrally mounted and has a longitudinal position, while the transmission is installed at the back of the engine. A driveshaft from the transmission goes by the engine all the way to the front axle where it enters the viscous couple mechanism, whose job is to distribute torque between the two axles. In normal conditions, just 15% of all torque is sent to the front wheels, which means that even though it has a four wheel drive system, the Audi R8 has the sports behavior of a rear-wheel drive model (which many consider to be a lot more fun than all-wheel drive or front-wheel drive). However, if something happens and more torque is needed to the front wheels, the system can go as high as 30%.
Active Sport Differential
The self-locking center differential used by the classic version of the quattro system usually does a great job distributing torque between the two axles, but to make things even more dynamic, Audi has introduced an additional component called sport differential. What this one does is to actively separate torque distribution. It is electronically controlled and it only needs fractions of a second to react. The electronic controller permanently calculates the perfect torque distribution ratio and adjusts it to suit every possible situation.
For example, a “regular” car usually tends to understeer during a tight corner approached at higher speed. By using the sport differential the experience gets quite similar to driving on rail tracks, because when accelerating and turning, torque is automatically sent to the outer wheels and this adjusts the car’s trajectory.
The active sport differential was introduced for the first time on the Audi S4 B8, which made its debut in November 2008. The differential was offered as an option and even though it added to the car’s total weight, it was designed to make the S4 behave more like a rear-wheel drive sports car, since weight distribution has always been an issue with the S4 (the front part has always been heavier).
“Crown Gear” Differential
Exactly 30 years after the quattro system was shown to the world for the first time, Audi took another important step forward by introducing a new and innovative system called the “Crown Gear” differential.
This new system replaced the Torsen center differential and it’s basically an open differential but with some key differences. Inside the differential, there are two new crown wheels that are directly connected to the central carrier and spider gears. In normal conditions, the two crown gears rotate at the same speed and send 60% of torque to the rear wheels and 40% to the front ones. But if the situation requires it, the system can adjust the distribution ratio and send as much as 85 of all torque to the rear axle or, if the rear loses traction, as much as 70% to the front axle.
This is one of the most efficient systems in what concerns torque distribution between axles and definitely the most advanced version of the quattro system ever created by Audi. It was introduced for the first time in 2010 on the Audi RS5 and has also been used on the A7 Sportback and A6.
The Ingolstadt based car manufacturer usually offers this system in combination with an intelligent electronic braking system called Torque Vectoring, which can separately break each wheel that loses traction, significantly improving the car’s sport behavior and safety.
What about the quattro’s future?
The past is all shiny, but what does Audi have in store for the quattro technology? Well, the German car maker is already testing a prototype of the Audi e-tron, a hybrid vehicle that uses an advanced four wheel drive system. They also seem to be very close to launching a production version of the Audi Quattro, a modern interpretation of the car that wrote history for them. The concept was initially unveiled at the 2010 Paris Motor Show to celebrate 30 years since the original Quattro was launched. It was based on the Audi RS5, was powered by the 2.5-liter TFSI engine producing 408 hp and featured the sixth generation of the quattro system. There were countless rumors about whether it will ever go into production and Audi never confirmed or denied these rumors.
On the contrary, at the Frankfurt Motor Show in 2013 they unveiled a new version of the Audi Quattro Concept, this one powered by a hybrid powe rtrain that had a combined power output of more than 700 hp (560 hp coming from a 4.0-liter twin-turbo V8 and around 150 hp from an electric motor powered by a lithium-ion battery). The two engines can run independent from each other, but when they work together, the Quattro can accelerate from 0 to 62 mph in 3.7 seconds and reach a top speed of 305 km/h (189.5 mph). According to rumors, we might see a production version of this beauty hitting the streets in 2015.
Another interesting concept Audi has unveiled at the 2013 Frankfurt Motor Show is the Nanuk Concept. Designed by famous Italian company Italdesign Giugiaro, it represents a new type of vehicle, a combination between a crossover and a sports car. Looking like an evolution of the Audi R8, it’s actually the carmaker’s vision of a car that could be driven in a sporty matter on all sorts of surfaces, not just tarmac or asphalt. It is powered by a longitudinal mounted V10 diesel turbocharged engine that produces 544 hp and 1,000 Nm of torque and its performance figures are quite similar to the Quattro’s: 0 to 62 mph in 3.8 seconds and top speed of 305 km/h.
Each way we look at it, the quattro’s system future seems to be in good hands and it will probably continue to thrill drivers for generations to come. How about you? Have you driven or owned a quattro Audi so far? Don’t hesitate and share your opinion with us.