Stratified DSG TCU Tune Preview

Stratified TCU Tune Preview

This video shows some of the shift logic that the nearly completed update to the Stratified Automotive Controls TCU tune for the Mk7 GTI will bring.  This update is for the DQ250 DSG.  The video primarily highlights changes with the on-pedal upshift response.

As my prior posts have discussed, this tune uses driver pedal input to determine shift rpm.  This is common for all TCU tunes I have tried, but the goal for these revisions has been to create a range of response from the drive (D) mode that I have not experienced with other TCU tunes.

When watching the video and seeing the gear shifts occur you cannot conclude that an upshift occurs at any specific RPM without knowing what the pedal position was at the time of the gear shift.  This is illustrated in the example below which shows the target on-pedal up-shifting response, the red line, versus the actual shifting response, the blue dots:

Stratified Automotive Controls Gear Change Example
Stratified Automotive Controls Gear Change Example

For each percentage of pedal position input there is a target engine speed where the shift from 1st to 2nd will occur, the red line.  The car is driven and the true up-shift engine speed for a sampling of pedal positions is recorded.

Example note: The chart above shows the gear shift response from the old baseline tune and the first cut at what target response should be, these values have all changed over several updates to the tune.

Development note: Initially this was a very laborious process until I created a macro in excel to filter out data of interest.

With the actual versus desired results Stratified was able to adjust the TCU tune to move the actual results closer to target.  This process was repeated until the actual performance was satisfactorily close the desired values.

Changes in the Stratified TCU tune consist of:

  • On-pedal up-shifting in all gears
  • Off-pedal down-shifting in all gears
  • On-pedal down-shifting across all gears except for 2nd to 1st