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Audi has used two different types of automatic gearboxes in their cars, the Multitronic CVT (Continuous Variable Transmission) and the S-Tronic Dual Clutch, and even though Audi has chosen to discontinue the CVT transmission for upcoming models, there are plenty of Audis that use the CVT transmission still on the market, both new and used. If you are trying to decide which Audi transmission is better for you, let’s look at how each transmission works.
A CVT transmission has no fixed gears, which means there are no traditional gears that run from first to sixth but rather there are two pulleys connected to each other by a belt. One pulley is connected to the car’s engine, and the other pulley is connected to the transmission and wheels. The pulleys are designed in a way that they appear to be changing size infinitely, from small to large. This is achieved by having each pulley shaped like a cone.
When taking off, the belt at the pulley connected to the engine is at the narrowest end on the cone, and at the pulley connected to the transmission is at the widest end of the cone. As you gain speed, and would traditionally change to sixth gear, or your cars highest gear, the belt shifts to the widest end of the cone for the pulley connected to the engine, and the pulley connected to the transmission will shift the belt to the narrowest end of the cone.
Benefits of a CVT Transmission
- The car can adjust to the best rev-range for any given situation
- Since there is no need to change gears, the drive feels continuous and smooth
- Since the car can quickly adjust to the best rev-range, economy is improved
Disadvantage of a CVT Transmission
- The car will quickly to a rev point and stay at that point while the car is accelerating, which many drivers describe as feeling like having a clutch slip
- You lose the immediate throttle response that drivers are used to, and can make gaining speed to overtake a little more difficult
Dual Clutch Transmission
A dual clutch transmission, as I’m sure you’ve already guessed, has two clutches to manage gears. Clutch A is used on odd numbered gears – first, third, fifth and seventh. Clutch B is used on even numbered gears – second, fourth and sixth. The two clutches are designed to work with each other to make changes between gears smoother and quicker by reducing the time the clutch takes to move from gear to gear.
When you start your car and move it from park to neutral, clutch A prepares first gear and clutch B prepares second gear. When you shift to drive, Clutch A moves first gear into position, and as you begin accelerating, clutch B begins to spin second gear to match the rotational speed of the first gear. When it’s time to gear up, clutch A moves first gear out of position, and clutch B moves second gear into position making the change over from first to second instantaneous. Once second gear is in position, clutch A picks up third gear, and spins it to match the rotational speed of the second gear, and create the same effect for the change from first to second for second to third. This process repeats through all the gear changes.
Benefits of a Dual Clutch Transmission
- Acceleration is improved.
- Gear changes are smoother than traditional automatics
- Throttle response is maintained from manual versions
Disadvantages of a Dual Clutch Transmission
- There is no improvement on downshift time from traditional automatics
- Higher maintenance costs
- Mechatronics unit can go bad leading to expensive repairs
Whether you decide on a dual clutch transmission or a CVT transmission, you can rest your mind in knowing Audi is supplying you with the best transmission for your needs. Should you have questions, are looking to have some work done on your Audi, or have an Audi in need of a new or repaired transmission, please feel free to contact us at Foreign Affairs Motorsport, South Florida’s Premier German Auto Repair, Performance & Race Facility Since 1978.