The Porsche PDK 7-Speed Transaxle (991.1 Carrera / Carrera S) is a seven-speed dual-clutch transaxle.
First gear is 3.91:1 and 7th is 0.62:1. Divide one by the other and the overall spread is 6.31:1. That is a very wide spread. With seven gears to share it out, the steps in the middle can still stay civil.
7th is an overdrive at 0.62:1: the output shaft turns faster than the input shaft. Two of the seven gears are overdrives. No gear is exactly 1.00:1, so there is no direct drive.
The biggest step is 1st to 2nd, where the ratio drops 41%. The smallest is 4th to 5th at 17%. A drop that size lands the engine well down the rev range after the change, so it pays to know where the torque lives.
It is a transaxle, so the final drive sits in the same case: 3.44:1 as listed here. The speed table uses that figure and nothing else. With a 3.44 final drive and 225/45R17 tyres, 7th at 6,000 rpm works out at 336 km/h (209 mph), and first runs out at 53 km/h (33 mph). That is how tall the gear is, not a top speed. Drag and power decide that. At 70 mph in 7th the engine turns about 2,010 rpm.
Ratios
| Gear | Ratio | Step |
|---|---|---|
| 1st | 3.91:1 | - |
| 2nd | 2.29:1 | 41.4% |
| 3rd | 1.65:1 | 27.9% |
| 4th | 1.30:1 | 21.2% |
| 5th | 1.08:1 | 16.9% |
| 6th | 0.88:1 | 18.5% |
| 7th | 0.62:1 | 29.5% |
| Final drive | 3.44:1 |