Some new information from ZF Group mentions how to extract the best acceleration from a CVT-equipped MINI:
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Select "SD" [SportDrive] by pushing the lever to the right. Floor the throttle pedal past the resistance point [detent switch position] to the maximum travel ("floored" in AT mode) and hold it there until engine rpm reaches approximately 5,500rpm [which happens quickly!]. Just before the gearbox "shifts", decrease the throttle pedal until the detent switch clicks off and then hold the throttle pedal in this new CVT mode position until the desired top speed is reached.
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[12/20/03 Edit: This suggested technique may be fine theoretically, but it seems very hard to do smoothly in practice. Starting out floored is easy, but easing the throttle pedal just before the gearbox shifts is next-to-impossible; something major is changed (Target Speed?) such that acceleration is disrupted. This needs to be tested.]
The smooth CVT mode gives marginally better acceleration than the stepped automatic transmission simulation of AT mode, which is what was found earlier in the Objective Testing thread here on MINI2.com.
ZF Group uses some terms we've not introduced in these threads before to describe two behaviors controlled by the gearbox and software:
CVT mode and AT (Automatic Transmission) mode.
CVT mode is the native condition of the gearbox and the "CVT" behavior is how its design and functionality are engineered to perform. This mode of operation has the transmission execute very smoothly while the motor is held to a fixed rpm near maximum torque.
AT mode is an optional software coding simulation -- engaged by an extra switch on the throttle pedal -- that delivers behavior something like a stepped six-speed automatic transmission. This was requested by the customer (MINI/BMW) to help with acceptance of the CVT gearbox in the marketplace.
The "detent switch" or "kickdown switch" which we've talked about (the click you can sometimes hear when you floor the throttle pedal) is this engagement of AT mode switched by depressing the throttle pedal past the resistance point.
