The DSG box takes the basic idea of pneumatic clutched boxes a step further. The heart of the DSG comes from the fact it has two clutches. The basic idea being that the gearbox can then have two gears engaged at any one time, one driving the car, the other waiting to take over.

The clutch arrangement is setup for odds and evens, where clutch 1 operates the 1-3-5 gears and clutch 2 operates 2-4-6.

DSG works by allowing the software to decide what gear the car will need next, and then pre-selects it. If you are accelerating, it will have the next gear up, and likewise if decelerating, the next gear down.

The system can then watch for a change signal - this is either done by clicking the corresponding paddle by the driver, or if in full auto mode the computer - and the gearbox can then tell the currently disengaged clutch (the one driving) to engage, and at the same time tells the engaged clutch (the pre-selected gear) to disengage. In this way the driver and passengers do not experience the on-off-on feeling associated with manual gearboxes. Instead, the gear change feels much more like that of an automatic gearbox.

However, because the change happens so quickly - around 8 milliseconds - the engine can maintain drive and the losses involved in the gear change are much reduced. This can be seen visually in the video below.

The video clearly shows the benefits of the DSG vs a very quick-changing manual driver.

The DSG gearbox is obviously controlled by computer, and this adds other benefits as well, even over race-going Sequential Manual Transmisions.

The computer in the DSG box monitors many of the cars sensors, these can be RPM, speed, angle of steering input, amount of wheel spin, braking and g-forces. It can then use these inputs to make decisions on which gear the car has to be in at any one moment.

For example, if you are approaching a tight corner you may want to change down two or even three gears. The computer sees that you are braking heavily, and that steering input is being applied, and can then change down either more quickly, or skip gears altogether and shift from sixth into third in one step. This allows the driver to keep the RPM in the best range for drivability. Likewise, if driving in snow or mud, the computer sees that there is a lot of wheel spin at low speeds, it can then shift up into a higher gear to allow the wheel spin to be controlled.