Because the launch of Unbound Vol. 6: Head to Head, now we have been using the Audi hype prepare to have fun the automaker’s return inside Want for Velocity’s digital world.
We now have uncovered the in-game updates and even regarded again on our prime 5 tuned Audis featured on Speedhunters through the years. However for this week’s theme, we’re taking you all again to high school… quattro college.
You’ll discover a quattro variant of just about each manufacturing Audi in 2024. But its origins date again to the Seventies, with engineers Jörg Bensinger and Walter Treser extensively credited for pioneering (and being the driving pressure behind) the expertise forward of its world debut within the 1980 Ur-quattro street automobile.
Then, as Audi rolled it out inside their rallying marketing campaign from 1981 onwards, it shortly turned obvious this all-wheel drive revolution was right here to remain. Not solely did Audi declare two World Rally Championship titles and 24 victories between ’81 and ’86, however there hasn’t been a two-wheel drive winner of the WRC since Lancia’s 037 in 1983.
Audi’s quattro is perhaps probably the most famend all-wheel drive system on the planet, but it surely wasn’t the primary of its sort – not by an extended shot. Early four-wheel drive transmissions date again to the inception of the inner combustion engine. Dutch brother Jacobus and Hendrik-Jan Spijker paved the best way in 1902 with their Spyker 60 H.P.
Within the following many years,, a number of 4×4 methods have been developed for navy and off-road use, together with the Willy’s Jeep and Collection 1 Land Rover.
What about ‘regular’ vehicles? Nicely, Jensen’s FF from 1966 and Subaru’s Leone in 1971 each utilised all-wheel drive lengthy earlier than Audi joined the celebration. What made quattro completely different was how it powered all 4 wheels.
Relatively than use a heavy, inefficient switch field to drive each axles, Audi developed a lighter, smaller centre differential to ship the ability entrance and rear. Then, when traction turned much more restricted, the centre diff might be locked with a vacuum-operated button, permitting the entrance and rear diffs to rotate on the similar pace with out slipping.
However the true sport changer got here in 1987 when Audi launched the Torsen (torque sensing) centre diff. Not like different methods, this one allowed Audi to repeatedly break up the ability between axles when wanted. So moderately than sending energy 50:50, it may ship something from 25 to 75% to the axle with probably the most grip. That form of tech appears commonplace now, however rewind almost 4 many years and you’ll see why quattro gained such a repute in each passenger vehicles and motorsports.
In 2024, the time period ‘quattro’ now is available in a number of variations relying on mannequin and meant use – some you’ll already be aware of, others possibly not. So, seize a pen and paper; class is now in session.
Inception: When Did It All Start?
Again in 1976, Walter Treser discovered himself as the pinnacle of Audi’s ‘Superior Particular Autos’ program. Certainly one of his earliest duties was to supervise the key improvement of an all-wheel drive, high-performance automobile as instructed by Audi CEO Ferdinand Piëch.
The venture didn’t actually have a correct title, with the unique prototype mannequin merely often known as A1 (standing for all-wheel drive primary). What’s extra, no person past Piëch and the Audi engineers – together with Treser and Bensinger – knew concerning the plan. Particularly not Volkswagen.
The story goes that whereas chatting with Volkswagen’s head of chassis improvement in Ingolstadt, the engineer boasted to Treser about how nice the dealing with was of their four-wheel drive, off-road VW Iltis, earlier than shortly making an off-hand remark about how good it’d be if the Iltis may have much more energy to outshine its rivals.
Listening to this, Treser turned extra intrigued with the concept of utilizing all-wheel drive in a sporty passenger automobile, both a coupé or two-seater. Piëch shared the identical view, which finally turned the inspiration for Audi’s first four-wheel drive manufacturing automobile, the Ur-quattro. Ur means ‘authentic’ and quattro means ‘4’… in Italian.
Nevertheless, the Ur-quattro was nearly known as one thing completely completely different. Carat – quick for ‘Coupé All-Wheel-Drive Turbo’ – was the title favoured by the Audi board, however on account of this title already being utilized by a woman’s fragrance model, it was Treser’s earlier suggestion (Audi quattro) that reigned supreme.
Introducing Torsen
‘Torsen’ would possibly sound like one other Audi engineer, however the time period truly means torque-sensing. It was this improvement in 1987 that really revolutionised the best way all-wheel drive transmissions work.
Within the first Ur-quattro, an open centre differential was used with the power to lock it manually through a dashboard change. However from 1988 onwards, this was changed by a Torsen differential – the Kind 1 – which allowed engine torque to be despatched mechanically to both axle relying on which one wanted it probably the most.
By default, the break up supplied a 50:50 distribution, however as grip or traction modified, as much as 80% of obtainable torque might be despatched to both axle with none want for handbook enter.
This wasn’t with out its limitations, nonetheless. Like a traditional limited-slip differential, the Kind 1 Torsen is restricted by the quantity of torque that is ready to be provided to an axle. So if one axle has no grip, the opposite axle received’t be delivered substantial torque, both.
To try to fight this, Audi initially supplied the second-gen Quattro with a manual-locking rear diff. Later advances (and a shift to electronically-controlled differentials) meant that every nook of the automobile might be monitored to restrict wheel spin and permit torque from a low-traction wheel to be handed through the Torsen diff to high-traction wheels as an alternative.
What About Haldex?
Within the case of early quattro methods, Audi used a longitudinally-mounted engine with a centre differential to supply everlasting all-wheel drive, with the power to shift torque between axles with the Torsen centre diff.
However what about these predominantly front-wheel drive Audis? Merely, ‘Haldex’ refers back to the title of the unique producer, and this drivetrain was designed to supply non-compulsory all-wheel drive on these front-wheel drive vehicles fitted with transverse-mounted engines. Assume first-gen TT and S3 fashions, for instance.
To maintain the packaging tight, Haldex makes use of a multi-plate clutch on the rear differential (moderately than a centre diff) to interact the rear wheels, when obligatory, moderately than being completely pushed like in earlier fashions. The draw back? Due to the clutch positioning and the entrance wheels all the time being pushed, earlier Haldex fashions may solely ship as much as 50% of the obtainable torque to the rear axle. Because of this – for probably the most half – Haldex didn’t really feel ‘correctly’ quattro in comparison with the fashions earlier than it, one thing Audi addressed later down the road…
quattro extremely
For many trendy Audis, quattro ‘Extremely’ is what’s generally used. This (because the title suggests) is one of the best of each worlds, combining conventional torque-sensing with the power to run front-wheel drive with out the drawbacks.
Why would you need to primarily run front-wheel drive? Nicely, Audi discovered that 90% of driving doesn’t require energy sending to all 4 wheels. Anybody who’s seen a dyno graph will know that all-wheel drive saps energy, which in flip makes use of extra gasoline and reduces total effectivity.
The answer? Use an electronically-controlled clutch on the rear differential (similar to Haldex) however with one other clutch additionally situated on the transmission, disconnecting the driveshaft altogether. Based on Audi, this improves gasoline effectivity by almost 20%.
The enjoyable doesn’t cease there both with quattro extremely. By taking knowledge obtained from the varied sensors across the automobile (together with GPS place and outdoors temperature), Audi’s quattro extremely system may even predict when a driver would require entrance or four-wheel drive with out another intervention wanted.
What About The Rear-Biased Audi R8?
To this point, we’ve checked out quattro in transverse and longitudinally-mounted types. However what concerning the oddity to the vary – the mid-mounted, V10-powered R8 supercar? Naturally, this has a novel quattro variation which makes use of an electronically managed hydraulic multi-plate clutch.
Due to the heavy engine within the rear, by default, the R8 is rear-biased with a break up of 85% to the rear axle and 15% to the entrance. However, when the grip or driving necessities change, an electrical axial piston pump (which might construct as a lot as 40bar of stress in only a few milliseconds) presses the friction plates inside the clutch collectively, permitting fixed variation of torque between the entrance and rear axles.
In second-generation variations of the R8, this even permits quattro to distribute 100% of obtainable torque to both the entrance or rear axle. However in the event you actually desire a rear-wheel drive R8, the R8 RWS constructed between 2017 and 2018 is your reply. It’s lighter, quicker and everlasting rear-wheel drive solely.
What’s Your Favorite?
That’s a whole lot of tech to digest in a short while, and we all know this barely scratches the quattro floor earlier than you level out what we’ve missed. However quattro is Audi’s celebration piece in spite of everything; this tech not solely put them on the map again within the ’80s, but it surely continues to take action even into 2024 with extra automobiles than ever boasting all-wheel drive.
Naturally, this status has yielded some fairly particular quattro editions through the years, from the screaming IMSA GTO race automobile to the Le Mans-winning R18 e-tron. But when we had to decide on only one? We’re going five-cylinder and 5 doorways – the Audi RS2 Avant.
A quick wagon developed with Porsche that additionally boasted quattro within the early Nineteen Nineties? Even by right this moment’s requirements, they’re obscenely cool – and quick.
Tell us your favorite quattro-equipped Audi within the feedback part.
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