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      02-14-2012, 06:40 PM   #1
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Clutch Drop Vs Launch Control

So I searched for this and couldn't find any answer. I am wondering what is the mechanical difference between 6MT clutch drop and DCT launch control? Sorry if I am totally off.
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      02-14-2012, 06:42 PM   #2
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Might as well ask about dinner too...
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      02-14-2012, 06:43 PM   #3
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You beat me to it! Lunch control means you wont drop your sandwich when you take off!
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      02-14-2012, 06:44 PM   #4
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Good question. I'd guess that DCT cuts Mcdonald's out of your diet.
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      02-14-2012, 06:53 PM   #5
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Assuming you're dropping your clutch at 5,500 RPM (or the same rev as launch control), the only difference is that the 6MT won't shift for you. Other than that, there should be no difference, as all traction control nannies need to be off for LC to be active.
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      02-14-2012, 07:05 PM   #6
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Think launch control slips the clutch and tries for more traction. A bit different than just dropping the clutch.

Last edited by sensi09; 02-14-2012 at 07:17 PM..
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      02-14-2012, 07:25 PM   #7
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I would imagine since launch control for all intents and purposes is a computer driven operation, it's a little easier on the drivetrain and related components. I believe your gonna burn out a clutch on hard launches before you wear out a DCT completely. A hard launch in a manual is a much less precise operation therefore goodbye clutch faster. Of course my opinions have no basis in fact, as usual.
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      02-14-2012, 07:25 PM   #8
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Quote:
Originally Posted by sensi09 View Post
Think launch control slips the clutch and tries for more traction. A bit different than just dropping the clutch.
This is also my feeling. During launch control, it seems like the computer balances clutch slip and tire slip to maximize traction and keep the engine in the power peak (8300 RPM) in first gear, a bit like a CVT.

Doing a WOT drop clutch in a 6MT is similar to just hammering the throttle on a DCT: nice burn out, but sub optimal launch.
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      02-14-2012, 09:53 PM   #9
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Cool guys, thanks
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      02-14-2012, 10:42 PM   #10
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Originally Posted by Nine View Post
Might as well ask about dinner too...
LOL... I knew someone else would be all over that...
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      02-14-2012, 11:20 PM   #11
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Might as well ask about dinner too...
Haha fixed
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      02-14-2012, 11:27 PM   #12
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Quote:
Originally Posted by username11 View Post
As anyone who has actually "dropped the clutch" with the E9X M3 will tell you, doing so will get you nowhere but some bunny hops as the diff sends power to opposing wheels and a resulting slow launch.

Some slipping of the clutch and careful throttle modulation are mandatory; I assume this is what launch control does.
I have tried it few times, one time worked pretty well, the rest of the times I got the result you just mentioned.
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      02-15-2012, 07:56 AM   #13
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Quote:
Originally Posted by aajami View Post
Assuming you're dropping your clutch at 5,500 RPM (or the same rev as launch control), the only difference is that the 6MT won't shift for you. Other than that, there should be no difference, as all traction control nannies need to be off for LC to be active.
I have disagree with you on this one, aajami. Although you must turn off DSC to activate LC, once you do activate LC, I believe it retakes control of the traction control system and runs its own special program to help you get a good launch.

Quote:
Originally Posted by PhillyNate View Post
I would imagine since launch control for all intents and purposes is a computer driven operation, it's a little easier on the drivetrain and related components. I believe your gonna burn out a clutch on hard launches before you wear out a DCT completely. A hard launch in a manual is a much less precise operation therefore goodbye clutch faster. Of course my opinions have no basis in fact, as usual.
I don't have facts either - but I agree with what you are saying.

I don't have time to look it up, but, I believe that there is some details about how LC works in either the original M-DCT press material or the M3 aftersales material provided to technicians. My recollection is that there is a lot going on with the ECU in order to provide maximum acceleration. Of course, as we know, it doesn't always necessarily work out as you might hope.
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      02-15-2012, 11:04 AM   #14
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Quote:
Originally Posted by mkoesel View Post
I have disagree with you on this one, aajami. Although you must turn off DSC to activate LC, once you do activate LC, I believe it retakes control of the traction control system and runs its own special program to help you get a good launch.
Interesting. It makes sense for the system to work as you describe, though that must mean there must be a significant amount of clutch slip to prevent wheelspin.
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      02-15-2012, 11:23 AM   #15
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Quote:
Originally Posted by username11 View Post
There was a thread recently where a guy was surprised by breaking traction when using snow tires and launch control . What did emerge of use from the thread is that the general consensus is the M3's launch control (disappointingly) does not utilize traction control a la Porsche's method but instead simply modulates clutch and throttle.
Could very well be.

Nevertheless, in the end, this still means that there is a difference between LC and just doing a clutch drop with a 6MT car. Specifically, the car's electronics intervene and either try to make the launch more effective or less harsh on the equipment, or both.
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      02-15-2012, 08:08 PM   #16
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Quote:
Originally Posted by 808@702
You beat me to it! Lunch control means you wont drop your sandwich when you take off!
My apologies for my previous post. I just got it now. My bad.
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Last edited by NFAM3; 02-17-2012 at 11:31 AM.. Reason: Stupid post
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      02-18-2012, 12:24 AM   #17
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Quote:
Originally Posted by username11 View Post
As anyone who has actually "dropped the clutch" with the E9X M3 will tell you, doing so will get you nowhere but some bunny hops as the diff sends power to opposing wheels and a resulting slow launch.

Some slipping of the clutch and careful throttle modulation are mandatory; I assume this is what launch control does.
I actually tried it few more time with DSC completely off and with around 4000 rpm, it works without any problem. Now i need to experience launch control in a DCT M3 to see the difference
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      02-18-2012, 06:16 AM   #18
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Quote:
Originally Posted by Prince_of_Persia
Quote:
Originally Posted by username11 View Post
As anyone who has actually "dropped the clutch" with the E9X M3 will tell you, doing so will get you nowhere but some bunny hops as the diff sends power to opposing wheels and a resulting slow launch.

Some slipping of the clutch and careful throttle modulation are mandatory; I assume this is what launch control does.
I actually tried it few more time with DSC completely off and with around 4000 rpm, it works without any problem. Now i need to experience launch control in a DCT M3 to see the difference
Be careful Prince, I'm afraid if you try LC in a DCT you may jump ships to the DCT awesomeness.
Anyway, I don't think any good driver can ALWAYS shift right at 8400RPM when DCT would do it. I always drive my DCT on the manual sitting (S) and I HATE the automatic one (D) but of I think I need to go thru 1-4 redlining, you can't beat D for that.
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      02-18-2012, 12:33 PM   #19
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Quote:
Originally Posted by username11 View Post
As anyone who has actually "dropped the clutch" with the E9X M3 will tell you, doing so will get you nowhere but some bunny hops as the diff sends power to opposing wheels and a resulting slow launch.

Some slipping of the clutch and careful throttle modulation are mandatory; I assume this is what launch control does.
What he said.

Clutch dumps are for AWD vehicles that you are beating on...gotta use more finesse with the M3.
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      02-18-2012, 02:02 PM   #20
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Quote:
Originally Posted by sameh
Quote:
Originally Posted by Prince_of_Persia
Quote:
Originally Posted by username11 View Post
As anyone who has actually "dropped the clutch" with the E9X M3 will tell you, doing so will get you nowhere but some bunny hops as the diff sends power to opposing wheels and a resulting slow launch.

Some slipping of the clutch and careful throttle modulation are mandatory; I assume this is what launch control does.
I actually tried it few more time with DSC completely off and with around 4000 rpm, it works without any problem. Now i need to experience launch control in a DCT M3 to see the difference
Be careful Prince, I'm afraid if you try LC in a DCT you may jump ships to the DCT awesomeness.
Anyway, I don't think any good driver can ALWAYS shift right at 8400RPM when DCT would do it. I always drive my DCT on the manual sitting (S) and I HATE the automatic one (D) but of I think I need to go thru 1-4 redlining, you can't beat D for that.
I know I will love the launch control in DCT, but definitely 6MT has its own benefits
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      02-18-2012, 09:44 PM   #21
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Quote:
Originally Posted by username11 View Post
Not sure I understand this. With DCT you need to go through a multi-step procedure which takes at least 10-15 seconds to get launch control. Which makes it kind of a toy you use to show your friends in a parking lot. With 6MT you simply feather the clutch and properly roll on the throttle and go, every time and anytime you want.

Also 1-2 at redline is one of the easiest shifts in this car with the 6MT. It's lower RPMs that cause people difficulties.

I thought one of the benefits of 6MT was you always had "launch control" aka your two feet. Am I missing something?
You are right, but 6MT doesn't have the launch control feature (although you can do it yourself). I think it is cool that DCT has that feature, but which one would I choose? Still 6MT for sure!
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      02-19-2012, 03:24 AM   #22
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Launch control is just a stupid feature that has little point other than to accelerate the wear on your drive train. Had 4 M3s and never used it once.
I'd be surprised if you couldn't get similar acceleration from standstill in a DCT car by pressing smartly on the gas and modulating any wheelspin with the throttle (old school).
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