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      04-21-2009, 09:00 AM   #1
A/J
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is the dct lag just for paddle shifting?

sorry for being a bit naive, but i was looking at possibly changing to a dct from my 6mt ...and i was wondering if the dct lag occurs in fully automatic mode too?

can someone explain the lag in simple terms...again sorry for teh newb question just wanted to see if this should put me off?
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      04-21-2009, 11:43 AM   #2
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There were a few "lag" issues with the DCT. The issue of slow shifting in S mode (paddles) has been resolved with recent software updates. After getting the latest update (31.2 AFAIK), shifting in S6 is FAST...and fricken awesome.

The ongoing lag issue is in D (auto) mode during low speeds. This typically happens when slowing for a corner in a residential area. Get back on the throttle and there is a lag before it goes. Also, if you do a rolling stop, it will lag for about a second.

Also, if you keep the car in an S mode, there is nearly no lag at all in the above conditions. The problem is, for the most part, contained to just the D modes. Hence, if you are doing some slow speed driving and know that the car is going to lag, simply switch to an S mode and manual shift it. then you can go back to D mode once you are moving along again. This is what mode people are doing (or leaving it is S all the time). Personally, I use D mode a lot around town. If I get into a residential area, I switch to S mode. When I get back rolling on the main drag, I go back to D.

So, there you have it. Without reading through 10,000 threads on this, it is summized above.... you're welcome. lol

edit: I love the DCT on the whole and am glad I got it. The shifting in S6 is stellar! It spins the wheels when shifting into 2nd gear and ocassionally into 3rd, depending on temps and surface conditions. I think you should try to drive a DCT first to see if you like it. Again, I am happy with my choice....and I bet you will like it too.
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      04-21-2009, 02:37 PM   #3
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cheers tim! ...that answers my q fully!

....i think am going to make the switch to dct because im finding the 6mt v tough for london (traffic) driving. (i hope the above is true for the uk market)

can i ask tho are we expecting a similar fix for the full auto mode?
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      04-21-2009, 04:41 PM   #4
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Quote:
Originally Posted by A/J View Post
cheers tim! ...that answers my q fully!

....i think am going to make the switch to dct because im finding the 6mt v tough for london (traffic) driving. (i hope the above is true for the uk market)

can i ask tho are we expecting a similar fix for the full auto mode?
We don't know for sure. Apparently, they are working on yet another software revision. Nobody has heard what it addresses to my knowledge. I heard it was due out sometime around May. I know the main complaint the last couple of months (and really way before that) has been the low speed lag issue. Many of us have complained to BMW and also filed complaints via the federal govt. (NHTSA I believe). We are confident it will get resolved.

The other issues people complained about were resolved AFAIK. Mine certainly were....but we will have to wait and see what they do about the low speed lag issue. If enough people complain, they will look into it, I am sure.

They did issue a TSB about a SIMILAR issue in SI B 28 07 08 which states "during a rolling stop situation, which is followed by a heavy acceleration demand, the transmission goes through a series of downshifts in order to match the appropriate gear with the high load signal". Well, I can tell you that this is NOT the case in my car. I can see that the car is in 2nd gear, so "a series of downshifts" does not need to happen. Secondly, I am barely on the throttle, hence, "heavy acceleration demand" is also not present either.

So, even though BMW is aware of a low speed lag issue, they actually did not really address it in my case (and with many other people too). They claim that this is normal behavior for the DCT. IF, I was slamming on the brakes and then tried to floor it, I could understand the tranny would be wondering wtf I am doing, and what it needs to do in response. However, when creeping along at 20 mph, braking gently for a speed bump, then gently giving it a bit of throttle, I cannot see how the tranny is confused!

I think they will address the issue and figure it all out in the near future. I think nearly all of us with DCT have complained to some extent about the issue. Let's hope they are listening and "fix" it correctly.

If they keep blowing me off, they will probably not have a return customer.
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