Launching with a DCT

[Diver]

What is the best way to launch a car with a DCT short of using launch control?

Is it safe to hold the brake and take the revs up to 1500 while in gear?

I want to get off the line with no bog, but no big noise either.

[Diver]

Originally Posted by maxnix

Sounds like a good way to overheat and accelerate the wear on the clutch material to me.

Torque braking is abuse, even on a true automatic.

I just punch my DCT and it goes. Seems like some other owners are experiencing different things. Even a manual clutch has to be let out.

What I am starting to think is the move from off the brake to on the accelerator (full) has to be very quick. Thanks for the answer on torque braking. As it happens my old G35 coupe would bog without torque braking.

From what I have noticed, pressing the sport button is a must unless in bumper to bumper traffic. DTC can be left alone if the roads are smooth, but hit a bump and it gets in the way.

[DWRAT]

If your above the 1200 mile breake in just floor it and it will rev and dump the clutch for you.
If you not over 1200 miles it is a dog out of the hole.

[bogart]

I can't get the flag to come up on the instrument panel... even after I drive around for a while (I heard it has to do with the car being warmed up or having been driven at least 6-10 miles).

I push DSC once, so DTC shows up on the instrument panel, I put the transmission in manual mode, and sport mode. I hold down the brake and ease on the gas, but it never goes above 1,500 RPM and the flag never shows up.

Any ideas?

[Diver]

Originally Posted by DWRAT

If your above the 1200 mile breake in just floor it and it will rev and dump the clutch for you.
If you not over 1200 miles it is a dog out of the hole.

Are you referring to launch control?

[jkp1187]

FWIW, I just got back from the One-Day M School at the Performance Center, and the instructors there explicitly told us NOT to use the brake to launch a Bimmer with DCT, because it would burn out the clutch.

And let me tell you, it's not like we were otherwise going easy on those cars.

[Nishan]

How are you supposed to launch without the brake? I would have thought that the car can handle launch control, especially if they catered for the flag signal!

[AW128i]

Originally Posted by Nish 135i M DCT

How are you supposed to launch without the brake? I would have thought that the car can handle launch control, especially if they catered for the flag signal!

What they mean is that you shouldn't hold the brake and accelerator at the same time, like you might when you "brake torque" a standard automatic equipped with a torque converter. With a torque converter, the fluid coupling allows the engine to pick up RPM while the brakes prevent the car from moving. This causes a heat build up (if done for an extended period of time or with excessively high engine speeds) in the transmission, but is otherwise pretty much harmless to the transmission. This helps the engine build torque for the launch, particularly in turbocharged cars because it allows the engine to build up boost, too. With the DCT (and VW/Audi's DSG), applying the accelerator pedal causes the computer to start to engage the clutch. If you're holding the car with the brake pedal, you're essentially forcing the clutch to slip more than intended...not at all like what is going on with a torque converter automatic.

If you want to "launch" a DCT-equipped vehicle, you should use launch control. Otherwise, just take your foot off the brake and then quickly apply pressure to the accelerator pedal.

P.S. It's my understanding that all DCT-equipped cars have launch control, but maybe they don't??

[dmboone25]

Originally Posted by bogart

I can't get the flag to come up on the instrument panel... even after I drive around for a while (I heard it has to do with the car being warmed up or having been driven at least 6-10 miles).

I push DSC once, so DTC shows up on the instrument panel, I put the transmission in manual mode, and sport mode. I hold down the brake and ease on the gas, but it never goes above 1,500 RPM and the flag never shows up.

Any ideas?

Are you north of 1200 miles? You have to be to engage the launch control...

The car must be driven for 10 KM or 6.2 miles continuously first...hit the sport mode, put it into manual 1 and hit the DSC so that DTC comes up.

Put your left foot on the brake and put your right foot on the gas--push it all the way to the floor, past the resistance point.

The flag should come up and the car will rev to about 3000 RPM. Let off the brake and keep the gas pedal floored and away you go.

One thing I have noticed is that 3000 RPM produces nothing but wheel spin...I usually let the revs fall down to the 1500 range and then let off the brake, which gives you a small chirp as you blast forward...

The car is a dog without the Sport button and manual shift modes engaged, at least compared to my 2008 MT 135--it almost feels like my old E92 328i....

[bogart]

Originally Posted by dmboone25

Are you north of 1200 miles? You have to be to engage the launch control...

The car must be driven for 10 KM or 6.2 miles continuously first...hit the sport mode, put it into manual 1 and hit the DSC so that DTC comes up.

Put your left foot on the brake and put your right foot on the gas--push it all the way to the floor, past the resistance point.

The flag should come up and the car will rev to about 3000 RPM. Let off the brake and keep the gas pedal floored and away you go.

One thing I have noticed is that 3000 RPM produces nothing but wheel spin...I usually let the revs fall down to the 1500 range and then let off the brake, which gives you a small chirp as you blast forward...

The car is a dog without the Sport button and manual shift modes engaged, at least compared to my 2008 MT 135--it almost feels like my old E92 328i....

Thanks, I will try that out again.

[dmboone25]

Originally Posted by bogart

Thanks, I will try that out again.

No problem at all--for whatever reason, it took me 2 or 3 tries to get it to work...maybe the launch control works that way at first, to ensure that we know what we are doing.

[Diver]

Originally Posted by jkp1187

FWIW, I just got back from the One-Day M School at the Performance Center, and the instructors there explicitly told us NOT to use the brake to launch a Bimmer with DCT, because it would burn out the clutch.

And let me tell you, it's not like we were otherwise going easy on those cars.

Well, other than launch control, what did they say?

[dmboone25]

Originally Posted by jkp1187

FWIW, I just got back from the One-Day M School at the Performance Center, and the instructors there explicitly told us NOT to use the brake to launch a Bimmer with DCT, because it would burn out the clutch.

And let me tell you, it's not like we were otherwise going easy on those cars.

That's really interesting...the owner's manual actually tells you how to do this...

[BSM 335I]

Originally Posted by maxnix

Sounds like a good way to overheat and accelerate the wear on the clutch material to me.

Torque braking is abuse, even on a true automatic.

I just punch my DCT and it goes. Seems like some other owners are experiencing different things. Even a manual clutch has to be let out.

So does slipping the clutch. Each time you initiate launch control your clutch get's worn (not significantly but some) Same goes for true manuals.

[dmboone25]

Originally Posted by maxnix

Not when launch control is not employed!

Citation please.

I was inferring the use of launch control....

[thinkbig]

holy .. I'm confused... so do we use the breaks or not? some of you are saying that it will burn the clutch and others say to break..

i'm a newbie!

[teddyb]

Originally Posted by bogart

I can't get the flag to come up on the instrument panel... even after I drive around for a while (I heard it has to do with the car being warmed up or having been driven at least 6-10 miles).

I push DSC once, so DTC shows up on the instrument panel, I put the transmission in manual mode, and sport mode. I hold down the brake and ease on the gas, but it never goes above 1,500 RPM and the flag never shows up.

Any ideas?

I tried to engage launch control right at 1200 miles and it wouldn't do it until about 1230 or something.

Since then it's worked fine, just make sure the car is really warmed up and dont forget to tap into m mode. A couple times i just moved it over to s and nothing happened.