Gearshift Strategies

Gearshift Strategies

The established gearshift strategies of Tiptronic S have been largely retained for the new 911 Carrera and 911 Carrera S. These are complemented by the new special function Sport Chrono as well as modified shifting functions for when the PSM function is OFF.







The automatic program provides the familiar programs which are activated automatically or via the corresponding driving strategy. The shift points are continuously adjusted between the user-friendly basic gearshift program and the sporty program, according to the style of driving.

Similarly to the 911 Carrera (996), model year 2004, the automatic program is also influenced by the following functions:
- Suppression of upshifts during rapid throttle lift, for example before a corner.
- Earlier downshifts when braking depending on the driving speed and deceleration.
- Adjustment of the shift points due to incline detection. Here gradients or ascents are identified by comparing the actual and desired acceleration.
- Adjustment of the shift points as a function of the geographic elevation.
- Suppression of upshift in corners depending on the driving speed and lateral acceleration.

Despite all of the functions listed, there will be driving situations in which it makes sense to be able to manually override the automatic program via the one-touch switches on the steering wheel. This function is also integrated, i.e. pressing one of the switches on the steering wheel will execute the corresponding function even if the selector lever is in position "P".

The selected gear is maintained for at least 8 seconds. The holding time is extended depending on the driving conditions (deceleration and lateral acceleration). The system then automatically switches back to automatic mode. Kickdown results in an immediate return to the automatic program.

The selector lever must be moved to position M if the driver wishes to shift the gears. The gears are then changed manually using the one-touch switches on the steering wheel. In this case the permissible shifting speeds are monitored and the gearshift only executed if the engine rpm limits are adhered to.

Upshift Suppression With "PSM OFF"







The 911 Carrera and 911 Carrera S are equipped with an upshift suppresser which takes effect when the "PSM OFF" switch is active and the manual setting is selected on the gear shift lever, in order to enhance the sporty character of Tiptronic S. Upshifts are prevented when the engine speed limit is reached in the "M" position, allowing the engine to run in the range of the speed limiter. The same also applies in position "D", in one-touch mode for temporary override.

When kickdown is activated, however, upshift will be effected when the engine speed limit is reached.

Reving Function During Deceleration State

Examples of downshifts in deceleration state include automatic downshifts when braking or downshifts activated via the one-touch switches on the steering wheel. This function initiates revving for downshifts in deceleration state to reduce shifting times, to improve shifting comfort and to actively prevent the rear wheels locking. The EDTC function (engine drag torque control) also stops the rear wheels locking as part of PSM, however it does so in response to detection of impermissibly high rear-wheel slip. In contrast, the revving function via Tiptronic S prevents active locking of the rear wheels in overrun state.