What is a DSG gearbox?

Buying a new car doesn’t have to be difficult – after all, that’s why we started carwow. But sometimes just choosing the equipment for your new wheels can be tough, thanks to indecipherable acronyms and new technology.

To help, we’re here with a series of guides to help explain some of the more modern technologies that you might not have seen on a car. This week, we’re looking at DSG gearboxes.

If you’ve recently looked at purchasing a car from the Volkswagen stable then you might be familiar with the acronym DSG. Called S tronic on Audis, it stands for Direct-shift gearbox (forgive us for referring to it as a DSG gearbox for the sake of clarity) and is the normal automatic transmission fitted to Volkswagen, SEAT, Skoda and Audi models.

What is it?

If you can’t tolerate complex technical explanations, all you need to know is if a car is fitted with DSG it means it’s automatic. Just like a traditional auto, you can slot it in ‘D’ and pootle about at your own leisure and it’ll shift gears for you – and like an auto you can come to a stop and pull away without fear of stalling or having to use a clutch.

You can also select ’S’ mode (it stands for sport) – which makes the car holds onto gears longer for better acceleration – or ‘M’ for manual, allowing the driver to control the gear selection using the lever or using (flappy) paddles mounted behind the steering wheel.

You still don’t need to worry about over-revving the engine by shifting down at high revs – the DSG unit is packed with electronics to look after itself.

How does it work?

Warning: mild geek content!

Engines have to keep spinning to work, but cars cannot constantly be moving, so you need a coupler between the engine and the wheels to avoid stalling the engine when the car comes to a standstill.

A traditional automatic gearbox uses a torque converter to connect the engine to the gearbox; essentially two propellors facing one another in a sealed chamber of fluid. When the one connected to the engine spins, it imparts its torque (turning force) on the facing propellor and pushes the car forward. It is this system that makes the car ‘creep’ at junctions when the brake is released.

A DSG auto replaces the torque converter’s fluid connection with a pair of computer-controlled clutches. With this in mind, it may be easier to think of a DSG as a manual gearbox that has a computer operating the clutch and gears. Using a pair of clutches means that as one clutch disengages a gear, the other clutch engages the next at the same time, effectively eliminating the time spent in neutral between changing gears.

What are the advantages?

Automatic gearboxes are becoming increasingly popular but traditionally make a dent in performance and fuel economy. This is because the fluid connection in a torque converter naturally loses some of the engine’s power, increasing fuel consumption. Clutches don’t suffer this problem, so in certain applications DSGs are as, or even more, efficient than their manual equivalents.

As demonstrated by the current seven-speed or the upcoming 10-speed (yes, ten gears!) unit, these ‘boxes often come with more ratios than a manual. This is beneficial because the engine can rev lower when cruising, thus using less fuel. It also means the car can accelerate harder, because having more gears spreads out the engines power more effectively.

Finally, critics often criticised traditional torque-converter autos for not being as exciting or involving to drive as manuals because you don’t have total control over the gear selection.

DSGs go some way to rectifying this because gear changes happen much quicker than a normal human can change cogs in a manual, and DSGs can be controlled using  paddles on the back of the steering wheel, for the budding Lewis Hamilton in all of us.

Any drawbacks?

There aren’t many considering that Volkswagen, SEAT, Skoda and Audi all use the technology across their ranges. For the most part, DSGs represent a significant improvement over traditional autos for their extra performance and efficiency. In fact, the main downside for most will be the increased purchase price.

They aren’t perfect though. The fluid connection offered by a torque converter means the way the car ‘creeps’ off the line feels very natural as torque builds in the converter. This isn’t the case in a DSG where the computer has to realise you’ve stepped of the brake and will then engage a clutch to mimic the ‘creep’ function. While it’s been well programmed it still doesn’t feel as natural as a torque converter.

It’s also worth noting that reversing in a DSG car requires a very light touch on the accelerator. Our favoured tactic for not shooting backwards violently is to just pop the car in reverse and take your foot off the brake – it’ll eventually creep backwards at a sedate pace. Touch the accelerator and you’ll often career backwards a bit faster than you thought you might.

Want to impress your friends?

Well, impress might not be the right word – but our other tech-made-simple guides will help you on the road to choosing your next car. If you’ve always wanted to know how electronic handbrakes work, whether lane assist can let you drive hands-free or even if adaptive cruise control will take the stress out of driving, then take a look at our jargon-free guides.

comments powered by Disqus