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02-22-2012, 05:20 AM | #1 |
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DIY DCT Launch Control (Have I discovered something here?)
Right guys, I think I may of stumbled across something here whilst trying to find the best way to launch my 135i DCT.
Now some of you may remember my previous thread/problems I had a few months back when trying to run my moddified (Flash tuned) 135i @ the 1/4 mile track.. http://www.1addicts.com/forums/showt...ight=santa+pod Since that day it has bugged me to the bone that I haven't been unable to extract the full potential from my car at the track due to the LC being next to useless when the car has some extra ponnies under the bonnet (those that have tried will know what I mean), unless of course you have DR's . Without LC you basically have to launch the car from tick over revs and wait whilst the turbo lag has bogged off before you actually get anywhere. This is obviously not ideal when running a car over the 1/4 mile and thus resulted in my poor 60ft times. Unlike the earlier Steptronic cars with the conventional auto, it is not possible to 'Brake Boost' a DCT car. As soon as you apply any throttle whilst on the brake peddle the computer just spoils the fun (DCT owners will again know what I mean). The other problem with LC, is it only works whilst DSC is only half dis-engaged (stability control still on) and this also spoils the fun when cutting power in 1st whenever I have tried running the car at the track. So whilst in my car yesterday, I decided to have a play about and see if it is possible in any way to dial in some revs from a standstill when launching the car, but only whilst having DSC fully dis-engaged. Voilą... As you can see by the camera going flying, it's certainly affective.. All I have basically done is switched DSC totally off, gearbox into M and sport button on (although I don't think the last 2 have any affect) and pumped the accelerator/gas peddle quickly... This then makes the revs jump up and you can then feather in what revs you want (about 2.5k seems about right for me) before realsing the brake pedal and holding on . Give it a try guys, it seriously works Just need to get my car back to the track now and see what she can do.. If this has already been discovered and discussed then apologies and I shall slope off with embarrassment to the nearest corner.. Last edited by Vtec Abuser; 02-22-2012 at 05:30 AM.. |
02-22-2012, 08:39 AM | #2 |
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Just browsing the forum and came across this thread. I take it from your post that you have an aftermarket ECU tune and that is causing launch control traction issues? Just trying to understand what's going on! Also, even with DTC activated, the ECU cuts power? I guess that's because the DSC is detecting unwanted yaw movements?
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02-22-2012, 09:27 AM | #3 | |
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It needs to be set at around the 2500rpm mark once the car is tuned IMO. Or even better, allow you to drop the revs (by lifting off the throttle slightly) to what you would like to launch at (something the LC on VW's DSG does).. Either way, I shall be using my new technique from now on |
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02-22-2012, 09:35 AM | #4 |
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I'm totally trying this today. And it seems so basic I can't believe noone has tried this/ figured this out yet. Nice job.
Btw, you sound just like Hans from the first Die Hard, was cracking me up :-)
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02-22-2012, 10:12 AM | #6 |
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tried it just now and didn't work for me.. could they be different models???
I'm running '11 DCT, N55... Also your dtc off light is different than mine.. i get a circle with a warning inside, not the slipping car.. |
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02-22-2012, 10:14 AM | #7 |
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In the video, the DSC is turned off. The "warning in a circle" comes on when the DTC is activated; i.e., first press of the DTC button. Press it and hold and the DSC will be turned off and you'll get the same symbol you see in the video. Or, at least this is how it works in the U.S.
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02-22-2012, 10:22 AM | #9 | |
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I think the panels must be different on different models then.. anyway, i'll try it again later, but when I did, I pumped the gas pedal and the car kept trying to move.. |
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02-22-2012, 10:22 AM | #10 |
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02-22-2012, 10:25 AM | #11 |
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As above mate, it'll be to do with the DME update at a guess. AFAIK once you have the latest update DSC OFF symbol changes to the one you see in my vid..
Some one may be along in a minute to confirm.. Anyone else had a go yet? |
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02-22-2012, 10:34 AM | #12 |
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I don't see how it could change, because it's not just the symbol on the little orange screen.. It's also the symbols on the all dark part where the other light go off (indicators, cel, etc)
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02-22-2012, 11:35 AM | #14 |
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When had my SW update done last March my DTC (dynamic traction control) light was replaced with the skidding car(MDM-like) icon. Before that my car had the yellow circle. This is what I have when I fully turn off all the nannies now...
Its been has been reportd here that latest SW updates do not use this(above) skidding car icon anymore. Current SW updates have reverted back to the old yellow circle. Its been speculated that BMW accidently gave us the MDM skidding car in our SW updates. I know when I had my SW updated with the dreaded added lag SW... and I got this new DTC icon... I felt the DTC and DSC worked MUCH better and did not cut the power as much as it did before the update. Perhaps BMW screwed up and was giving us the MDM software for our lowly 135i's. I don't think we will ever know. |
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02-22-2012, 11:45 AM | #15 | |
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02-22-2012, 12:20 PM | #18 |
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02-23-2012, 02:36 AM | #20 |
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To be fair, on occasions the LC can hook up and be a half decent tool (especially on a stock car). It's when any more power is added that it becomes a problem and anything but a snooker table like smooth surface would induce the stability control to cut in a suck the power from first gear.
During that run in the video I actually set off at more revs than I had planned on doing. However, on that occasion it seemed to hook up fine and even if it didn't, you would still be able to feed the power in yourself rather than the DSC taking over due to the fact that all aids were off! On other practise runs, I found that around 2000-2500rpm is where I need to be for the best launch. But more practice will determine that for sure.. |
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03-07-2012, 09:09 AM | #21 |
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I tried this today after a poor attempt of launching the car last night...
http://www.1addicts.com/forums/showthread.php?t=658527 Doing the technique described did not work, and I was not able to feather the throttle past 1,000rpm. Any others have problems?
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03-07-2012, 11:41 AM | #22 | |
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