Sequential (S) mode. In this mode, the driver has full control over shifting. Pulling the shift lever rearward in the "+" direction, or actuating the right-hand "paddle" on the steering wheel, effects upshifts; pushing the shifter forward ("-") or actuating the left-hand paddle effects downshifts. It's that simple:

• S1-5: Selected by the console switch and indicated in the instrument-cluster display, the programs range from "softest" to "firmest" - that is, in 1 the shifting is accomplished at a relatively leisurely pace, in 5 much more quickly. The driver's criterion here is how sportily he or she wants to drive; in any of the programs, the higher the engine speed the quicker the shift.
• S6: To select this most race-like program, the driver must switch off the Dynamic Stability Control system. Minimum shift time in S6 is 80 milliseconds; under equal conditions, the "slowest" shift program (1) takes 2-4 times as long to complete a shift.

Whenever and however the driver calls for a shift, the response of SMG is immediate and satisfying.


Automated (Drive) mode. Though automated, this DRIVELOGIC mode is not meant as a substitute for a conventional automatic transmission. Here there are five programs. As with S, the higher the program number the faster the shift; in D, however, the road/engine speeds at which shifts occur (up- and downshifts) also increase.


Additional capabilities and safeguards. Careful development of DRIVELOGIC has resulted in many fine points of the system's operation:

• 1st-gear start in S: As the vehicle comes to a stop in the S mode, DRIVELOGIC automatically selects 1st gear for starting off again; the driver will then effect upshifts as desired.
• 2nd-gear start: D1 can be used as a winter-driving program; it starts the vehicle from rest in 2nd gear to move off gently. (Dynamic Stability Control's traction function also guards against wheelspin.)
• Overspeed protection: If the driver calls for a downshift (S mode) that would overspeed the engine, the command to downshift is ignored.
• In any D program, a floored accelerator can get one or two downshifts depending on conditions, and pleasingly quickly.
• Slip detection: In both S and D modes, this safeguard helps keep the vehicle stable during downshifts, particularly when traction is low. Every 10 milliseconds, the rear wheels are checked by the DSC for slippage. If there is too much decelerative torque on the wheels, clutch engagement and engine speed are automatically adjusted to prevent too abrupt a downshift.
• Double-clutching. Also in both modes, DRIVELOGIC coordinates clutch disengagement, shifting, engine speed and clutch engagement to accomplish smooth downshifts - just as a skilled driver would.
• Hill detection: Depending on gradient, down- or uphill, the D shift programs are modified to ensure optimum gear selection. In S mode, shift times are shortened so that the engine is always "on point" for best acceleration uphill, or engine braking downhill.
• Intuitive shifts: In the D mode under certain circumstances, DRIVELOGIC modifies downshifts. In cornering, uphill driving or braking, for instance, a downshift will occur sooner than if the car were simply being driven steadily on level ground. This feature can seem almost supernatural in vigorous driving on a winding, hilly road: SMG seems to read the driver's mind, magically getting into the right gear before accelerating out of a corner.
• Grade assist: A "hillholder" function, active in both S and D modes. When stopped facing uphill, the driver actuates the left shift paddle. DRIVELOGIC "revs" the engine to about 1500 rpm and slips the clutch so that the vehicle does not roll back. This is available for brief periods only.
• Illuminated upshift indicator: The same orange LEDs that adjust the tachometer warning zone according to engine temperature help indicate to the driver when to upshift. Illuminating in 500-rpm segments, they light progressively as the engine approaches its redline (8000 rpm); given BMW M3's catapult-like acceleration, this can be an appreciated assistance.

A less elaborate SMG, with just two selectable shift programs within each of its automated and sequential modes, is available in the 5, 6 and Z4 Series.

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