| SMG Explained further |
| Practice Makes Perfect BMW turns race dreams to reality with the sequential-shift M3. But is it truly better? Not all of us are racers, but there's a bit of racer in all of us. BMW must reckon so, too, because you can now buy a new M3 with the option of a $4500 six-speed manual sequential gearbox. Repeat. A hard-edged, sequential manual gearbox, not a pretend semi-auto with a fluffy torque converter, but the real thing complete with a clutch. Just like the one Michael Schumacher uses in his flying F1 Ferrari. We're talking chink-chink bullet gear changes completed in 250 milliseconds, which is about the time it takes an ace to do the job in a regular M3. The only difference between BMW's SMG (Sequential M Gearbox) and Schuey's machine is that his box has no synchromesh and is able to execute changes in around 70 milliseconds. Then again, it only lasts around two hours... presuming all goes well. The M3 system takes this F1-inspired technology and modifies it to suit everyday road use. And, because it's so efficient, it actually increases the longevity of vital components such as the clutch and synchromesh, taking away the sometimes rough treatment most of us dish out in the heat of a red-misted blast. It's clever, sophisticated electro-hydraulic technology that took BMW M GmbH around three and a half years and $20 million to develop. SMG has four programmes: three automatic and one manual, the latter being the F1-style operation. But unlike Schuey's machine, the M3 uses a conventional gear lever to operate the system rather than buttons on the steering wheel, or paddles behind the wheel as on the sequential Ferrari F355 road car just launched in Europe. There's lots to learn about SMG before taking to the wheel, and when you do slide into the seat the absence of a clutch pedal is bizarre. The left foot's in limbo. When in self-shifting 'auto' mode, clutch operation and gear changes are made by a series of hydraulic valves taking instructions from a dedicated gearbox ECU, which is turn feeds off a brainier main ECU processing around 20 million pieces of data per second to ensure optimum god swaps. The main ECU is looking at information from the wheel sensors, ABS sensors and throttle position when talking to the gearbox. SMG designer Wolfgang Neshe says that main ECU is the smartest available on any road car, while the net weight gain of SMG is around 10kg. In theory, SMG is better than a conventional manual gearbox because of its greater shifting efficiency, and the 'smart' functions built into it. It won't allow a driver to change down one or more gears if it's going to over-rev the engine or create a compression lock-up in the diff, and it automatically blips the throttle on down changes for a heel-and-toe effect. In other words, it can almost make a good driver out of a complete Wally. But SMG takes a lot of getting used to. For example, BMW's semi-auto Steptronic sstem (and most others as well) require you to push upwards for an upshift and downwards fora down shift. With SMG it's the opposite: downwards for an upshift and upwards for a downshift. Then there's the matter of smoothing the gear changes. Because SMG is so true-to-form-manual, you've got to be extraordinarily mindful of what you're doing. If the throttle isn't lifted when changing gears the chassis will jerk when the cogs meld. A flashing light reminds drivers to change up when engine speed gears near the 75oo rpm red line, but there's a quirky and paradoxical sensation of the gear change taking forever because your role is reduced to a quick snick of the lever rather than being occupied using the clutch pedal and moving the gear lever the full distance on a conventional H pattern. Although SMG takes care of many functions, it doesn't eliminate the things we like doing with a conventional manual. You can still light up the rear wheels on take-off, even perform an F1 like traction-controlled start before such getaways were banned by the FIA. Wguke gears can be skipped when safe to do so, SMG also prevents stalling, and automatically finds first gear if you do spin to a stindstill. "I wish I had that on my sequential gearbox," quipped BMW super Touring driver Geoff Brabhan at the launch. All parameters are catered for with SMG, especially when left in 'auto' mode, which has three programmes- Sports, Economy and Snow. Sports hangs on to gears longer and chagnes rapidly, Economy swaps cogs earlier and creamier and the slippery surface mode eliminates first gear all together on take-offs and provides greater engine braking on down changes. When in 'auto' mode it's not just engine speed but also throttle input that determines when gears are changed. You more or less tell the M3 when to change gears by lifting off the loud pedal. Because it's an uncommon method it feels a strange way to drive. SMG is one incredibly complex, and at the same time brilliant, piece of automotive engineering. But does latest technology necessarily mean a better product? Does SMG make a sensational car like the M3 any better? BMW thinks so. We can't say for sure just yet, but would be surprised if SMG didn't ultimately add another dimension of driving enjoyment to this super car. SMG has potential, but it needs a large quantity or quality time behind the wheel to fully familiarise yourself with its workings and realise that potential. To gauge its worth you have to operate this gee-whizz sequential manual gear box to the point where it becomes second nature. So, BMW give us our 1996 PCOTY winner with an SMG to sample for around, oh, six months, and we'll get back to you.. |
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| SMG Page |
| .... extracted from Australia Motor Magazine September 1997 Issue. |