[rjahl]

Here is another example of what the BMW engineers had in mind when the set up the calibration files for the automatics.

Below is the deceleration time map for the 2>1 down shift in manual and sport mode. Deceleration is the time allocated for the oncoming clutch to slowly clamp and bring the engine and gearbox to the same RPM's. The map on the left if the stock 330 file, while the middle is the stock Z4 3.0SI value and the right is my current values. Axis is RPM, torque (Nm) and value is milliseconds.

Keep in mind that this is only ONE phase of the shift. A list of phases:

1. Pre-fill and stabilization; time allocated to pre-fill the oncoming clutch. 20 milliseconds for this shift
2. Zeit 2, Time used to switch the engine torque from the off going clutch to the oncoming clutch. About 200 milliseconds for this shift
3. Deceleration, time allocated for the engine and gearbox to synchronize speeds. This is also about the same period the TCU will request a reduction in torque output from the engine via the CAN bus.
4. Zeit 3. Just a soft ramp for the final closing of the oncoming clutch

So if you have a 330 auto, you push the paddle to downshift into 1st and you get to wait over one full second to complete the downshift. Yawn.

The calibration files are full of setting designed to keep things SMOOTH and have very little to do with performance or sportiness. Sure you need to be careful as you can easily push too much torque through the gearbox but so far I have not had to move any of the torque limiters to achieve really great results.