Cadillac STS-V Exact Shift Point Testing

This morning I made 2 runs to determine current shift points during acceleration from a standing start.

I ran the STS-V in “competition mode”; this mode apparently uses “Cruise mode” shifting, which was a surprise to me but means a different table for the transmission logic.

run1gearshift12

Run 1: From 1st gear the shift to 2nd started at 30 mph as programmed. The STS-V reached 6,180 rpm before shifting.  The shift took 0.2 seconds.  The 2-3 Shift started at 60 mph and the STS-V reached 6,310 rpm before shifting.

HP Tuners Information

HP Tuners Information

Run 2: From 1st gear the shift to 2nd started at 31 mph.  The STS-V reached 6,378 rpm before shifting.  The shift too 0.2 seconds.  The 2-3 shift started at 60 mph and the STS-V reached 6,240 rpm before shifting.  The latter is surprising since the logic appears to command the shift at 58 mph and not 60 mph.

With a goal of raising the shift points to 6600-6800 rpm, my plan is to increase the 1-2 shift speed from 30 mph to 31 mph.  In first gear, 140 rpm equates to 0.6 mph.  So a full mph increase in shift speed may raise the shift point by 230 rpm or so from 6,380 to 6,600 rpm. For second gear, 40 rpm is around 0.6 mph, so 200 rpm increase would be 3 mph, or 58 mph up to 61 mph.

I will plan to retest under similar circumstances to see how the changes effect the actual result.  What do you think?  The model predicts that hitting the proper shift points will produce a slight improvement in acceleration.  Have you done these type of adjustments to your car before?

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