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04-23-2011, 09:57 PM | #1 |
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DCT slow shifting on track
Today at LVMS I had slow shifting issue, it happened during a few sessions. I wonder if my tranny was overheated or what was wrong.
When the shift getting slow, it would take up to 2k-2.5k rpm delay to shift a gear. For example, if I up-shift in 2nd gear at 7k rpm, the rpm would hit 8.5k before shifting into 3rd, about 1 second delay. It happened at any gear as well, so I had to shift at 6k-6.5k rpm which was really annoying. However, I didn't see any warming or something unusual. Can someone shed me some light on what's going on? |
04-26-2011, 10:20 PM | #3 |
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What transmission mode were you in? Did it make a difference if you changed modes?
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04-26-2011, 10:36 PM | #4 | |
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For some sessions it shifted normal, and very crispy, but for others were not. I couldn't figure out why. |
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04-26-2011, 10:48 PM | #5 |
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Next time it happens try S4 for a few laps and see if it makes a difference.
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04-26-2011, 10:52 PM | #6 |
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04-27-2011, 06:39 AM | #8 |
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I haven't experienced it either. What I have experienced is some problems early in my first session on some track days where it failed to downshift. I usually run in S5 with M mode on. Probably should not use M-mode but I drive on a track with little run off and do not carry insurance.
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04-27-2011, 07:51 AM | #9 |
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I remember reading somewhere that S6 was not a good choice for the track.
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04-27-2011, 09:21 AM | #10 |
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I run s5 all the time on track and have had zero issues. Not sure what is going on, but good luck
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04-27-2011, 10:22 AM | #11 |
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Never faced this problem, try switching up settings and than going back to S5 or S6 depends whether you have DSC off or not. If it still persists, pit-in turn off the car, take your keys out and restart the car. The DCT transmission is strongly controlled by the ECU and sometimes you really never know with electronics.
I have overheated my transmission before in Willow Springs last summer, reached around 270F and they give a warning error light and the transmission will not shift at all until it cools down. Scary, because I could get my transmission over heated within 2 laps of willow springs albeit the ambient temperature was close to 95F. Other than that, I have tracked the DCT for over 15 trackdays and have no issues with it. If it still persists, stop by the dealership and ask them to take a look - obviously don't tell them that the problem existed on the track but rather hard driving on the road. |
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04-27-2011, 11:21 AM | #12 |
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could be that the transmission was getting hot. I agree with the others that you should give S4 a try. that's what I use 100% of the time (both on the street and on the track). I like S4 the most because it gives you the rev-matched downshifts, but doesn't give you as much of a power "surge" when upshifting, so it doesn't upset the chassis as much when you shift mid-turn.
I also have a DCT temp gauge in my car and I've noticed that with spirited driving and a lot of shifting, S6 generates more heat than S4. that's obviously not surprising, but I thought I'd throw that out there as a data point. |
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09-11-2011, 01:04 PM | #13 |
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This weekend two of us had this same issue. We were both on S4. We were at ORP which is 2200 feet and it was 92 degrees... Not sure what the equivalent temp would be at sea level.
Anyways, it was about a second delay. Sometimes if I breathed the shifting for a lap it would go back to normal...
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09-12-2011, 10:13 AM | #14 |
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Do you happen to know what version of the dct software you have??
Reason I ask is ESS said their DCT software made the clutch engage quicker and in return there was less heat. But ESS also said that if you had BMW's latest DCT software you would not need their software because it had been greatly improved and worked just fine with their kits 575+... |
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09-12-2011, 11:24 AM | #15 | |
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09-12-2011, 12:39 PM | #17 |
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You're just too fast Ricky :P
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09-12-2011, 12:40 PM | #18 | |
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A bit off topic. Can I see your rear seat closeout/delete?? I saw you have one in your sig and I am making one for myself at the moment and wanted to see as many as possible...? |
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09-12-2011, 12:43 PM | #19 |
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LOL~ I wish that's the cause.
My buddies just took some shoot yesterday. I'll post up once they finish. |
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04-03-2012, 06:33 AM | #21 |
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Can you tell us which oil cooler u used for the DCT please? Thanks
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04-03-2012, 09:31 AM | #22 |
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I've heard about that happening in S6 several times before. Seems like this mode is optimized for straight line acceleration, and not as much for track driving. The engine does not reduce power much if at all during the shift so there is great deal more slip and heat produced in S6. I am not fast enough to overheat DCT (also, it's cold here most of the time), but still prefer S5 and S4 for track driving to avoid traction loss while shifting 2->3.
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