Well I got the car back yesterday, and the software fix seems to have virtually eliminated the jerky stops! It seems SO much more appropriate that a car of this stature should do EVERYTHING smoothly. Now lets see how long the "fix" lasts.

 

thats great to hear. hopefully it works for me as well. the car shouldnt be downshifting at the last second into 1st anyways..the downshifting program of the std auto is quite crappy. even when coasting down a hill, you cant do it unless you shift into Neutral...otherwise the car keeps downshifting which results in engine braking. You have to keep touching the gas to even coast down a hill. never had this annoying behavior in my past cars

 

OK, my road trip is over. I took the opportunity to test a number of things out, especially as I sat in 3 hours of dead stop traffic (had only a 1/2 mile to go!) at the Mexican border at Lukeville, AZ.

"Grippy" stops - The brakes can definitely be feathered to a smooth stop. It takes more of a concerted effort that doing so in my previous Acura and my wife's Odyssey. If you have to stop quickly, it is much harder to be smooth because you have less time. I suspect I'll just get better at it as I drive the car more.

DSC in a disabled state had no effect that I could discern.

The gear selection process used by the transmission seems like it could be optimized is slow/stop-and-go conditions. Keeping the car in "D" in my aforementioned 3 hour ordeal caused quick acceleration to about 5MPH from brake-off, with no application of throttle. This was also seen in DS mode, and M1. I tried keeping the car in M2 and M3, and found immediate relief, with M3 being the best all around. The car would not surge ahead, and would only move slightly until I applied throttle. Removal of throttle allowed me to brake the car without fighting the idle surge. Much smoother stops as a result.

I don't know if running the car from M2 or M3 from a stand still is bad for the transmission. If anyone knows please speak up!

In all, I think the problem is clearly multifaceted:

- The car simply puts out too much thrust at idle in D, DS, and M1. Period. This seems to be worse with the A/C on, probably due to the higher idle. I don't think lowering the idle is a viable solution. I don't know if there is something that might be done in software to more intelligently control the gear selection, as it would slow down responsiveness (being in first from a stop is better). Maybe something with the clutches where they can more gradually apply the power from the engine to the wheel?

- The brakes can be feathered, most effectively when you're not fighting idle thrust. There is feel to the brakes, you just need to get used to it. I do agree that the brakes may be overboosted somewhat.

- DSC interaction - I can't rule it out completely. Does turning it off completely really mean it is not going to interfere with the braking somehow?

 

Thanks for the very detailed and useful update. Don't think it is advisable to move off from standstill in M3 but M2 should be fine. When in manual mode, say M3, M4, or M5 and when you glide to a halt, what gear is being shown on the counter? Is it M2 or M1. I always have M2 when I do this but when in full auto mode I believe it shifts down to M1 when the car comes to a complete stop. Can you confirm this? Thanks!

 

Thanks for the very detailed and useful update. Don't think it is advisable to move off from standstill in M3 but M2 should be fine. When in manual mode, say M3, M4, or M5 and when you glide to a halt, what gear is being shown on the counter? Is it M2 or M1. I always have M2 when I do this but when in full auto mode I believe it shifts down to M1 when the car comes to a complete stop. Can you confirm this? Thanks!

 

Thanks for the very detailed and useful update. Don't think it is advisable to move off from standstill in M3 but M2 should be fine. When in manual mode, say M3, M4, or M5 and when you glide to a halt, what gear is being shown on the counter? Is it M2 or M1. I always have M2 when I do this but when in full auto mode I believe it shifts down to M1 when the car comes to a complete stop. Can you confirm this? Thanks!

 

Thanks for the very detailed and useful update. Don't think it is advisable to move off from standstill in M3 but M2 should be fine. When in manual mode, say M3, M4, or M5 and when you glide to a halt, what gear is being shown on the counter? Is it M2 or M1. I always have M2 when I do this but when in full auto mode I believe it shifts down to M1 when the car comes to a complete stop. Can you confirm this? Thanks!

 

oops! sorry I posted my reply 3 times. My apologies!

 

My wife drives our 07 550i most of the time, I drive only it only on the occasional weekend trip. Having raced years ago, I pride myself on smooth driving. I just can't get to the car to come to a stop smoothly. I own a Mercedes/BMW repair shop, and am a ASE Master Tech. I am familiar with how these cars should work. I am convinced that the problem (at least in our '07) is brake pad material rather than a software issue. We are using ceramic pads on customer cars with great results. I loathe to think that our "free" brake linings are the problem, but it may be worth exploring. As our car only has about 6500 miles, we have a ways to go before a pad change. Has anyone changed to something other than a BMW pad compound?

 

can you try putting a diff pad on your car and try it out? im only asking because you run a shop and that swap shouldnt take more than a few minutes per corner.