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01-10-2006, 05:41 PM

#11

subterFUSE

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Join Date: Dec 2004

Location: Winter Park, FL

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My Ride: 2005 545i (SMG) Titanium Gray Black Interior, Anthracite Trim M-tech kit Sport Package Premium Sound Satellite Radio Active Cruise Comfort Seats Navigation Folding rear seats

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Interesting... I have only taken SMGs for a handful of test drives (though I am planning to include it on my new 550i) but the dealer told me basically the opposite: that you shouldn't lift your foot from the gas, even slightly, when shifting with SMG. I don't know that his word is gospel, but he is very knowledgable in most areas where the 5 series is concerned, moreso than most. I did find that the 1>2 and 2>1 shifts were the roughest, esp. in Auto mode, but like subterFUSE I was able to alleviate this by shifting at higher RMP, 4000+, though this may not be advisable during your break-in period.

You don't HAVE to release pressure on the gas to shift with the SMG. It is true you can just hold the gas down and shift up or down all you want.

But if you want your shifts to be silky smooth, you do need to change pedal pressure. I read the technique of "lifting foot inside shoe just before shifting" in an article where someone was test driving an M5 for a magazine, and they complained about the rough shifts to the BMW engineers who were at the test facility. The BMW engineers told the drivers to release slight pressure on the gas before shifting. I have been using this technique for some time now, and it works flawlessly.

The SMG can shift as seamlessly as the Steptronic, if you operate it a certain way. Shifting at the right times combined with releasing slightly the throttle pressure before shifting achieves this.

Here is what I have noticed.... The roughness in an upshift actually has to do with the moment when the next gear has been engaged and the clutch is being released. If you are adding throttle at the moment the clutch is released after a shift... then you get a jerk as the car accelerates. This is why after I release the pedal pressure with my foot, and shift the gear... I pause for a moment before applying more gas. I wait for the gear to engage, and the clutch to release before I try to accelerate in the next gear. Since I drive in Normal mode most of the time, this technique means my shifts tend to be rather long.... about 1 second for a shift from 1st into 2nd. If I switch to Sport Mode, it can be done just as smooth, but faster. .5 seconds or so.