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Thread: M3 DCT Question (Issue?)

              
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    M3 DCT Question (Issue?)

    I have recently upgraded from an e46 m3 (SMG) to an e92 m3 (DCT/DSG) and have noticed the following "issue"...

    In my "old" car (SMG) - I could be in 6th gear at highway speeds (70ish) and drop to 3rd by slapping the paddle 3 times very quickly. The transmission seemed to "skip" the downshift to 5th and 4th and go straight to 3rd gear - allowing for overtaking almost instantly. It was either imperceptible (the shift from 6th to 3rd) - or it was so quick that I didn't even notice it grabbing the other gears in-between. This, in my opinion, is how it should be.

    Now - with DCT - the upshifts are MUCH quicker, much less "jerky" - overall the transmission does everything MUCH better. A single downshift from 3rd to 2nd (or any other single gear) seems like it is also much quicker/better than SMG was. Rev-matching is also MUCH better than SMG - with SMG, I would modulate the throttle to get a "perfect" match - the new box is much better in this regard also.

    The "issue" that I am having is when I am cruising in 7th gear on the highway and I want to drop 3 or 4 gears down to 4th or 3rd. It seems to happen only in certain circumstances (maybe it's when the gear I am downshifting to is on the same shaft - i.e. 7/5/3/1?) - but I haven't pinned it down yet.

    There seems to be a very significant delay when dropping down this many gears - I am talking ~.5 seconds... Very noticeable - and sometimes (if using acceleration to get out of a situation) can be somewhat dangerous in my opinion. I guess my question is - has anyone else noticed this? Anyone else moved from SMG to DCT and have noticed the same? I am hoping it's not an issue with the gearbox, and it's just "how it is" - because I can kind of understand why there would be some delay (although this seems a little much) if you are dropping down to a gear on the same shaft as the current gear instead of just one gear on a different shaft (where it works beautifully).

    Hoping this makes sense. If anyone has any advice - please let me know, it would be much appreciated.

    Cheers.

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    I went to the DCT from my M6's SMG, I think I know what you mean. When I was test driving the M3, the sales guy even mentioned something about downshifting a few gears at once, he told me I had to go down gear by gear. I am not sure why this is, but my way around it is put it in D and gun it. It will downshift to 3 for you then you can go back to paddling and it will put you back in Manual mode.

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    Perfect - I will try that out.

    I almost never drive in D just because in the old M - the automatic mode was autotragic :-) I also like being in control of the engine - and listening to that glorious v8...

    My g/f likes the automatic mode in the new car (in the city) - and when in the passenger seat, it honestly feels as good as (better than?) a slushbox. She also gets more than 14 mpg in the city while I get much less... I guess old habits die hard for me.

    Looks like I have something to look forward to after work... Thanks for the tip!

    Cheers.

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    from what i have noticed if you throw your car in D and stop on the pedal you'll drop gear fast. For what works for me is i do each gear and just keep clicking down till i get it and its fast as hell.
    F10 M5 : ??????
    E90 M3: 11.2 126.7 with a 1.8 60ft Street Tires, Stock Interior,DSC on

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    SMG is better at downshifting.

    When this happens, you are likely in 5th or 6th gear and not 7th. The reason it happens is DCT has the next gear pre-selected, so to downshift it has to get out of that gear and then go get the lower gear. So if you are in sixth it is already waiting for 7th.

    DCT isn't perfect but it is built for shift speed when accelerating. SMG had better downshifts in IMO as well as better gear level feedback.

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    Click here to enlarge Originally Posted by akh23456 Click here to enlarge
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    from what i have noticed if you throw your car in D and stop on the pedal you'll drop gear fast. For what works for me is i do each gear and just keep clicking down till i get it and its fast as hell.
    I am just looking through old started threads, and thought I would update/bump this for anyone with a DCT...

    I learned this a while back, but never posted it. In manual mode, with DCT - if you depress the throttle fully in a high gear (6th or 7th gear, depress the throttle until the button is clicked on the floor) - AND THEN pull the left paddle to downshift, the transmission will SKIP ALL GEARS and go to the lowest optimum gear possible. I thought this was really cool, and not too many people know this. It works, and even the manual badly describes this process. It's the quickest way (by far) to pass a car.

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    ill have to put this to the test

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    Click here to enlarge Originally Posted by inlineS54B32 Click here to enlarge
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    I learned this a while back, but never posted it. In manual mode, with DCT - if you depress the throttle fully in a high gear (6th or 7th gear, depress the throttle until the button is clicked on the floor) - AND THEN pull the left paddle to downshift, the transmission will SKIP ALL GEARS and go to the lowest optimum gear possible. I thought this was really cool, and not too many people know this. It works, and even the manual badly describes this process. It's the quickest way (by far) to pass a car.
    Yes, this works.

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    Click here to enlarge Originally Posted by LostMarine Click here to enlarge
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    ill have to put this to the test
    It's pretty damn cool - I felt like an imbecile after learning this, and was skeptical - until I gave it a try... Prior to this (as I said in the first post) - I was not too happy about this, as this function was available with SMG II in my old M3. It's a nice little easter egg IMO.

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    Click here to enlarge Originally Posted by inlineS54B32 Click here to enlarge
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    I am just looking through old started threads, and thought I would update/bump this for anyone with a DCT...

    I learned this a while back, but never posted it. In manual mode, with DCT - if you depress the throttle fully in a high gear (6th or 7th gear, depress the throttle until the button is clicked on the floor) - AND THEN pull the left paddle to downshift, the transmission will SKIP ALL GEARS and go to the lowest optimum gear possible. I thought this was really cool, and not too many people know this. It works, and even the manual badly describes this process. It's the quickest way (by far) to pass a car.
    Click here to enlarge Originally Posted by Sticky Click here to enlarge
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    Yes, this works.

    Yup, I have tried it and it works very well. However I find that to do so you have to depress the pedal all the way until you click that "button" aka floor it, and by that time you are going significantly fast. I find it only useful with no traffic and you just need to punch it.
    Most of the time I am stuck behind a car and need to pass someone on the left and merge. I cannot simply go wot just to drop a few gears. That is when I think D mode is nice.

    I think BMW should have incorporated the merc or GTR (cannot remember) method of by holding the down paddle briefly, it will drop to the lowest optimal gear.
    ///Matthew
    Click here to enlarge

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    Click here to enlarge Originally Posted by MK599 Click here to enlarge
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    I think BMW should have incorporated the merc or GTR (cannot remember) method of by holding the down paddle briefly, it will drop to the lowest optimal gear.
    Agree. They also should have incorporated the Porsche launch control but BMW likes being difficult.

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    by depress, you mean press correct? as in press it to the floor, or at least past the kickdown?

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    Click here to enlarge Originally Posted by LostMarine Click here to enlarge
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    by depress, you mean press correct? as in press it to the floor, or at least past the kickdown?
    Yeah, same meaning.
    ///Matthew
    Click here to enlarge

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    Click here to enlarge Originally Posted by LostMarine Click here to enlarge
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    by depress, you mean press correct? as in press it to the floor, or at least past the kickdown?

    Right on - just press the throttle until kick down button is clicked (tried it in 6th and 7th - but prob works in 3rd+) and then downshift one click.

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    Lol - @MK599 - sorry bout that. +1ed

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    Click here to enlarge Originally Posted by Sticky Click here to enlarge
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    Agree. They also should have incorporated the Porsche launch control but BMW likes being difficult.
    Yeah, they left put things that a good software engineer could have incorporated damn quickly. For example, like the latest Ferrari boxes where you can hold the downshift paddle while braking for perfect blipped downshifts. Yes, you can do it on your own, but it's not as perfect as an algorithm. I agree, I don't know why they don't go the extra mile for things like that.

    Another good one, cars have just started adding horsepower and torque "meters". The technology needed to measure this was available via Mercedes when they put out the first car with yaw control/accelerometers. That was in the mid 90s - it took almost 20 years to present such simple data to the user. Click here to enlarge

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    Click here to enlarge Originally Posted by inlineS54B32 Click here to enlarge
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    I agree, I don't know why they don't go the extra mile for things like that.
    On the launch control I honestly think it is to make it more difficult for you to use so you don't.

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    Click here to enlarge Originally Posted by Sticky Click here to enlarge
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    On the launch control I honestly think it is to make it more difficult for you to use so you don't.
    LOL
    ///Matthew
    Click here to enlarge

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    Ha! Never thought of it like that. Keep the warranty claims low for screwed drive lines. Click here to enlarge

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    Click here to enlarge Originally Posted by inlineS54B32 Click here to enlarge
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    Ha! Never thought of it like that. Keep the warranty claims low for screwed drive lines. Click here to enlarge
    Exactly.

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    nice, I'll give this a try. The 7-DCT is normally so intuitive exept on those WOT multi-gear downshifts in "D" mode (Yes, I do drive in D2 mode).

    On a side note, I've managed to get the 7-DCT to make the car stall twice in the week I've had the car, both under the same conditions:

    A slow crawl after starting the car
    A oscillate between very light throttle and backing off the throttle (Like you would in a normal tight parking lot situation trying to maneuver the car out of the spot)
    Car stalls

    I've only had this situation happen once in my last E46 M3 with SMG, but that was an unusual circumstance where I had DSC on, the rear wheels spun on ice, and then they hit a dry spot on the road and the car stalled.

    Anyone ever had this happen? Should I bring something like this to my service advisors attention? Or maybe I'm just digging for reasons for them to update to engine software 240E for free? Click here to enlarge
    Loe P.
    - E90 LCI M3 7-DCT Interlagos Blue / Novillo Silver
    [K&N filter|MS pullies|test pipes|Evolve Stg II tune/Servotronic/GTS-DCT Tune|Euro MDM]

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    Spool twice,
    I was able to do the same thing during cold starts. If I started the car and immediately put it into reverse (think backing out of house garage) the car would almost sound like its stuttering. If I let the car sit in the garage for say 30seconds-1min before putting it into reverse it would solve the problem majority of the time. Had similar problems with my non FI 2008 M3. What fixed this for me tremendously and has helped my car even more on cold starts was getting the actual cold start program removed from the software. Anyone who does coding can do this for you or most tunes as well. I highly recommend it and others who have had the cold start program removed only have positive things to say. The cold start program really made the first few minutes of morning driving a bit annoying. Problem gone! If you are stock you can benefit quite a bit from a tune performance wise or if you want to go the cheaper route coding is like $60 and you can get some cool little tweaks done.

    Some tunes will also update the engine software to the latest 240E for you.
    ​2014 F10 M5 Competition Alpine White / Sakhir Orange
    Undercover Custom Downpipes & Connector. BMS Stage 1. IND Cosmetics. OEM CF Perf Spoiler.

    E92 M3 AA Gen 2 Lvl 3 586whp 398wtq SAE (sold)


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    Thanks for the advice, yes I am looking into tunes. I got a great discount offer from VF-E to try their tune, I may take that route and get the cold start delete. The intense ticking sound during the cold start is a little embarrassing.
    Loe P.
    - E90 LCI M3 7-DCT Interlagos Blue / Novillo Silver
    [K&N filter|MS pullies|test pipes|Evolve Stg II tune/Servotronic/GTS-DCT Tune|Euro MDM]

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    Nice! I haven't heard too much about the VF tune but I figure all of them are pretty similar.
    ​2014 F10 M5 Competition Alpine White / Sakhir Orange
    Undercover Custom Downpipes & Connector. BMS Stage 1. IND Cosmetics. OEM CF Perf Spoiler.

    E92 M3 AA Gen 2 Lvl 3 586whp 398wtq SAE (sold)


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