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    • Stock dual clutch E92 M3 takes on a stock E92 6-speed M3

      This is a debate that ranges all the time on the forums. What is faster, DCT or manual? Well, the dual clutch simply does shift faster and we see time and time again that the manual can not match it. This is a constant on every platform with a dual clutch and manual option (Porsche PDK versus manual direct comparison was posted earlier this year). The more shifts involved the bigger the advantage a dual clutch will have.

      On the M3 the DCT is geared much tighter in 1st, 2nd, and 3rd gears. The manual is geared better for the top end as it can stay in third longer (up to 113 miles per hour) than the dual clutch which has to shift to fourth much earlier. That is why you see the manual creep up in third gear in the video below but it still can not overcome the DCT shift speed advantage despite having lower drivetrain losses.




      This article was originally published in forum thread: DCT M3 VS 6 speed manual M3 started by LostMarine View original post
      Comments 121 Comments
      1. ERM324's Avatar
        ERM324 -
        DCT wins 5 out of 5 races, go figure...not sure how this helps your cause whatsoever (i posted this in the other thread) Click here to enlarge
      1. LostMarine's Avatar
        LostMarine -
        just posted in the other thread, didnt realize this is the one you posted.

        5 out of 5? you count the mis shift? you count the 2 that the MT starts to pull and dct lets off for fear of losing? then yea, 5 out of 5, but the footage shows a different view of this advantage
        winning the single race yes, yes, again, consistancy. but as for an actual HP or MPH advantage, its just not to matter..

        I consider it like the Coriolis Effect. SOOOOOOOOOOOO many other small but significant differences and changes/variations are going to have a 99999999.9999999% chance that you miss (lose) that you dont need to factor it unless going for a world record.. where that .015 (time/car) is going to be the difference
      1. leo985i's Avatar
        leo985i -
        Looks like there's barely any difference - all up to the driver.
      1. folgrz's Avatar
        folgrz -
        That guy in the 6MT can drive!

        I expected the DCT to pull more in between shifts

        Good runs
      1. blkclk550's Avatar
        blkclk550 -
        My point
      1. Autobahn335i's Avatar
        Autobahn335i -
        Maybe I miss the point, but DCT vs MT should only influence three things: shift speed, drivetrain loss and gearing. You could add consistency to the list.

        Pro and cons of points 2 and 3 may be arguable, but no one can deny a modern DCT simply shifts faster than a human can, even with the perfect shift. How much the difference is then solely depends on the DCT system. In the F458 it can shift in 50ms in race mode. No MT can match this.
      1. LostMarine's Avatar
        LostMarine -
        Click here to enlarge Originally Posted by Autobahn335i Click here to enlarge
        Maybe I miss the point, but DCT vs MT should only influence three things: shift speed, drivetrain loss and gearing. You could add consistency to the list.

        Pro and cons of points 2 and 3 may be arguable, but no one can deny a modern DCT simply shifts faster than a human can, even with the perfect shift. How much the difference is then solely depends on the DCT system. In the F458 it can shift in 50ms in race mode. No MT can match this.
        correct, but how much does that affect actual accleration, measured against a DT loss advantage to the MT, and gearing is about equal..
      1. Autobahn335i's Avatar
        Autobahn335i -
        Click here to enlarge Originally Posted by LostMarine Click here to enlarge
        correct, but how much does that affect actual accleration, measured against a DT loss advantage to the MT, and gearing is about equal..
        Per shift the DCT car will gain .x seconds. That's all, isn't it? Of course the MT car is not "standing still in time" while the driver shifts. But the DCT car will be able to accelerate again a tad earlier.
      1. Blaizon's Avatar
        Blaizon -
        Also the MT can negate some of the shift speed advantage of the dct due to gearing. The MT is staying in gear longer gear for gear add to that a competent driver and the match up should be fairly close stock for stock.
      1. LostMarine's Avatar
        LostMarine -
        Click here to enlarge Originally Posted by Autobahn335i Click here to enlarge
        Per shift the DCT car will gain .x seconds. That's all, isn't it? Of course the MT car is not "standing still in time" while the driver shifts. But the DCT car will be able to accelerate again a tad earlier.
        wouldnt the extra HP from less DT loss put the MT ahead to start with, or make up .x seconds?
      1. Autobahn335i's Avatar
        Autobahn335i -
        Click here to enlarge Originally Posted by LostMarine Click here to enlarge
        wouldnt the extra HP from less DT loss put the MT ahead to start with, or make up .x seconds?
        I'm not sure if DT loss affects real life performance much. Air drag, tire friction, even wheel weight will most probably have a bigger impact than drivetrain losses. Unlike on a dyno where these factors are ruled out.
      1. BrenM3's Avatar
        BrenM3 -
        I like turtles.
      1. Pea's Avatar
        Pea -
        This i my real experiance also, the difference is very small , there is also one thing that not been discusssed and that is that the software actually reduces power for a fraction of a second after shift in the dct car, i wonder how much that effects acceleration.
        This is the function that some tuners are using to save the clutches on tuned DCT M3s.
      1. KiokenM3's Avatar
        KiokenM3 -
        a 6 speed wil have the advantage the longer the race goes, but i gotta admit. the guy can drive!
      1. LostMarine's Avatar
        LostMarine -
        Click here to enlarge Originally Posted by Autobahn335i Click here to enlarge
        I'm not sure if DT loss affects real life performance much. Air drag, tire friction, even wheel weight will most probably have a bigger impact than drivetrain losses. Unlike on a dyno where these factors are ruled out.
        right, all these smaller things add much more to the equation than .0xx seconds faster acceleration from dct.
      1. JonsC63AMG's Avatar
        JonsC63AMG -
        I love DCTs.
      1. gareth.foley's Avatar
        gareth.foley -
        What's up guys? This is my video and it took me a second to find where it was on the forum (it says "as seen on BimmerBoost on YouTube"). History wise, my friend I raced in this video used to have a 2011 S5 with an APR intake, tune, and stAsis exhaust. I ran his S5 once last year resulting in my M3 taking a proverbial dump on him despite the mods. Since I had an M3 he jumped on the opportunity to pick up a Frozen Gray (know the previous owner of that car). I figured it would be interesting to see how much faster a DCT is vs 6 speed.

        As seen in this video I missed 3rd gear like a champ in the first run, pussy shifted 3rd in the third race (just wanted to make sure I hit it), and then I hit the rev limiter trying to stretch it out in the 4th run. Regardless, you can't make a mistake with DCT and that is seen here. I also think that the DCT transmission is geared better for the power band of the S65 but that's debatable.

        Click here to enlarge Originally Posted by folgrz Click here to enlarge
        That guy in the 6MT can drive!

        I expected the DCT to pull more in between shifts

        Good runs
        I was expecting my friend to pull more in between shifts too. It just never happened. I appreciate the compliment on the driving! Click here to enlarge

        Click here to enlarge Originally Posted by KiokenM3 Click here to enlarge
        a 6 speed wil have the advantage the longer the race goes, but i gotta admit. the guy can drive!
        Thanks for the compliment on the driving! Hard to believe I didn't learn how to drive stick until a few years ago lol.
      1. LostMarine's Avatar
        LostMarine -
        Click here to enlarge Originally Posted by gareth.foley Click here to enlarge
        What's up guys? This is my video and it took me a second to find where it was on the forum (it says "as seen on BimmerBoost on YouTube"). History wise, my friend I raced in this video used to have a 2011 S5 with an APR intake, tune, and stAsis exhaust. I ran his S5 once last year resulting in my M3 taking a proverbial dump on him despite the mods. Since I had an M3 he jumped on the opportunity to pick up a Frozen Gray (know the previous owner of that car). I figured it would be interesting to see how much faster a DCT is vs 6 speed.

        As seen in this video I missed 3rd gear like a champ in the first run, pussy shifted 3rd in the third race (just wanted to make sure I hit it), and then I hit the rev limiter trying to stretch it out in the 4th run. Regardless, you can't make a mistake with DCT and that is seen here. I also think that the DCT transmission is geared better for the power band of the S65 but that's debatable.


        I was expecting my friend to pull more in between shifts too. It just never happened. I appreciate the compliment on the driving! Click here to enlarge


        Thanks for the compliment on the driving! Hard to believe I didn't learn how to drive stick until a few years ago lol.
        Welcome! Thanks for making the video, and finding it, and signing up here. the 6MT vs DCT debate is old but still raging over here. I think im the ONLY person with a DCT to defend that DCT offers no real advantage against a properly driven 6MT, and have gone to lengths in a short period of time to prove this Click here to enlarge
      1. gareth.foley's Avatar
        gareth.foley -
        Click here to enlarge Originally Posted by LostMarine Click here to enlarge
        Welcome! Thanks for making the video, and finding it, and signing up here. the 6MT vs DCT debate is old but still raging over here. I think im the ONLY person with a DCT to defend that DCT offers no real advantage against a properly driven 6MT, and have gone to lengths in a short period of time to prove this Click here to enlarge
        No problem. Selfishly I make the videos to kill time and make some easy $$$ on the side (although YouTube mistakenly disabled revenue sharing on this video). I've been on this forum for awhile but since I'm not in the F/I game yet I mostly come and read the threads for information. When I ordered my car I opted to not go with DCT for a few reasons. First and foremost, I really do enjoy driving a M/T car as long as it's not a daily commuter. Since this car was going to be for fun and weekend driving I felt a manual would be the better choice for me. My second reason was to keep the price of the car down. I really didn't want to spend the extra money for something that would not give me any real benefit in the long run. For example, if the car was my only means of transportation I would have sided more with the DCT out of convenience. My final reason for not going with DCT is I don't want to spend the money later on to maintain it or potentially replace it. A drain and fill on a normal manual transmission is so easy that there is no reason not to do it yourself. The same goes for changing a clutch. I like working on my own cars and I know that the DCT would be something that I wouldn't want to go near with a 10 foot pole in fear of messing something up. I could be wrong on this but I'll stick with what I know when it comes to a car I'm going to own for a very long time. Click here to enlarge
      1. M&M's Avatar
        M&M -
        Ok so I think I can add some 1st hand input on this sticky debate.

        I have had a manual since 2009. Traded in in Jan this year for a DCT. So I have had both.

        In my manual, I ran plenty DCT's being in the scene I'm in. DCT had a huge advantage in the 1-2 shift. And a slight advantage in the 4-5 shift where you have to go across the gate. And of course the consistency.

        Apart from that there is not much in it WITH A DRIVER THAT CAN SHIFT SUPERFAST! The manual is actually stronger after like 110mph & actually comes back at the DCT & passes (all things being equal).

        When I had my manual I used to pass all the equally modded DCT's after 110. And when I got my DCT & ran 3 of my buddy's with equally modded 6MT's the same happened to me. I got out in front & they passed me around 120mph. All 3 of them. And yet we made similar hp on the dyno. The manual has longer gearing & that helps up top.

        But for 1/4 mile racing, the consistency & the momentum of the 1-2 shift makes the DCT king & hard to beat on the strip.