‘S Tronic’ didn’t quite make Elon Musk’s baby name shortlist, but the name perfectly aligns Audi’s pioneering transmission system with the brand’s innovative way of thinking.
Epitomised by their slogan ‘Vorsprung durch Technik’, or ‘Advancement Through Technology’, the German manufacturer has raised the bar time and time again through cutting edge technological enhancements.
When it was introduced in 2008, the S Tronic transmission was only available on a few models with longitudinal engines. Fast forward just over a decade and the S Tronic is available on a selection of Audi models ranging from the family-friendly Audi A3 Sportback to the Audi TT Coupe.
Dual clutch, seven-speed, dynamic performance. This is what Audi promised, delivered and solidified.
In this article we’ll explain exactly what Audi S tronic is, how it works, and what components make the S Tronic flourish. We’ll also discuss how the design and transmission improves performance while reducing fuel consumption.
What is S tronic?
S Tronic is a dual clutch, direct-shift gearbox (DSG) that allows your Audi to combine and/or switch between automatic and manual transmission.
By combining the efficient, sporty nature of a traditional manual gearbox with the convenience of an automatic gearbox, the S Tronic transmission delivers both compelling performance and affordable running costs.
The unique seven-speed, dual-clutch gearbox is what makes the S Tronic different to other Audi offerings like the six-speed DSG Multitronic, Tipttronic, and R Tronic.
The dual-clutch, seven-speed gearbox facilitates smooth yet rapid shifting with next to no interruptions in the power flow. The silky transmission enables dynamic acceleration which makes for exhilarating performance and a truly satisfying driving experience.
That’s not all. Audi’s innovative design of the S Tronic has ensured the system places great importance on fuel efficiency which plays its part in reducing fuel consumption and pollutant emissions.
What is the seven-speed S tronic?
The seven-speed S Tronic consists of two multi-plate clutches (K1 and K2) and two sub-transmissions that control the car’s gears.
Both of these transmission structures are continuously active when the engine is on, but only one is powered by the engine at any given time.
For instance, when a driver accelerates in second gear, third gear is already engaged in the second transmission section, which ensures gear shift transitions are effortlessly smooth.
Gears are switched over as the clutch changes - the K1 opens and the K2 closes. The gear change only takes a few hundredths of a second which eliminates the chance of any jolty or uncomfortable interruptions.
The larger K1 clutch directs the torque via a solid shaft to the gear wheel for all the odd numbered gears (1, 3, 5 & 7).
You then have a hollow shaft that rotates around this solid shaft. The hollow shaft is connected to the smaller K2 clutch, which is actually integrated inside the K1 clutch. Confusing, I know! Try and picture them as Russian dolls where the K1 engulfs the K2.
The K2 controls the gear wheels for all the even-numbered gears (2, 4, 6), as well as the reverse gear.
For models with longitudinally installed engines, Audi has designed a special variant of the seven-speed S Tronic, whereby the gear wheels for all gears are situated one behind the other on an output shaft.
Alternatively, Audi models with transversely installed engines are configured in a single layout with two output shafts. The S tronic for transverse engines come in three versions and is available in six or seven gears. The seven-gear S Tronic has two versions which is dependent on the amount of torque transmitted.
S Tronic Design
With each meticulously designed component, the S Tronic gearbox offers everything you’re looking for in a new car.
Audi has designed the seven-speed S Tronic for irresistible performance and high efficiency-action.
The dual-clutch transmission was initially designed for longitudinally installed engines and quattro all-wheel drive, however, Audi’s adaptability ensures that any models with transversely installed engines aren’t missing out on the action.
The S Tronic’s cutting-edge control unit commands economical driving and has been built to suit modern TDI, FSI and TFSI engines with their high torque even at low speeds.
S Tronic Internal Components
Audi’s overriding mechanical goal was to ensure that both multi-plate clutches were precisely working in unison. Through the combined forces of a compact pressure cylinder, electronically controlled rotation speed compensation and an optimised coil spring package, the S Tronic transmission was given the platform to achieve maximum precision and comfort during acceleration and gear changes.
The robust mechatronics module holds the responsibility of managing the transmission. The compact unit houses the control units and hydraulic actuators, which allows its control concept to vary the speed of the gear shifting process and control the necessary power output.
The power output flows from the drive shaft to the self-locking differential of the quattro all-wheel drive powertrain, which splits the power into two directions. 60% of the torque flows via the propeller shaft to the rear-axle differential and 40% via a side shaft to the bevel pinion of the front-axle differential.
On the subject of splitting the load, the S Tronic’s oil systems are split into two different systems. As the dual-clutch mechatronic module and oil pump are lubricated by their own oil circuit, the gear sets, front and centre axle differential are lubricated separately with hypoid gear oil.
Separating the oil systems has allowed the Audi engineers to equip their components in a suitable position without comprising the use of any unnecessary lubricant.
What driving modes are available with S Tronic?
The seven-speed S Tronic gives the driver the option of two driving modes: automatic mode or manual mode.
Opt for automatic mode, and you’ll have a choice of two driving programmes to choose from - either D (Drive) or S (Sport).
In D mode, the gear changes are supplied automatically by the S Tronic transmission, while S offers quicker, more potent gear shifts.
If you want to take charge of the gear changes yourself, manual mode allows you to do this via the selector lever or with the standard paddles behind the steering wheel.
How does the S Tronic affect performance?
When it comes to performance, the S Tronic will add a little sprinkle of va va voom to your Audi’s resumé. This is largely down to the launch control system, which truly fulfils the car’s acceleration capabilities.
The S Tronic is capable of producing up to 550Nm of brute torque and handling engine speeds of up to an exhilarating 9,000rpm.
The intelligent management of internal components allows the S Tronic transmission to produce lower fuel consumption when compared with a manual gearbox on the same Audi model.
Is the Audi S Tronic worth it?
If peak performance and smooth sailing is essential to your driving experience, then equipping your new Audi with S Tronic transmission is a no brainer.
Despite being slightly more expensive than a standard manual or automatic gearbox, the price difference is rather insignificant when you consider your cars improved performance and reduced fuel consumption.
With all the complex technology and high-tech components, is there a chance things can go wrong? If maintained, the S Tronic gearbox is consistently reliable, which is ideal considering the hefty maintenance costs. If you’d like to find out more, you can check out our Audi Reliability post.