Drag launch w/ DCT questions

[Skooterbrah]

Ok, first and foremost, i spent a little time searching, but I have found multiple conflicting answers, So i figured I would start a thread on this.

The car is going in for an ESS 625 next week, and the next Wednesday i plan on taking her to a test and tune night at the drag strip. My question is in reference to the DCT and launching the car.

I know there are 2 ways to launch, first being the actual launch control, 2nd being "poor mans" launch control where you just mat it from a dig and the engine automatically revs to 3500ish and then engages one of the clutches.

My question in reference to the above, is which mode is "safer" on the DCT its self. I have heard mixed feedback, saying that true LC is more wear and tear. Then I have heard that using the poor man method will destroy your 1/3/5/7 clutch in no time where as the standard mode is safer and recommended to use.

Any useful, proven feedback would be GREATLY appreciated, thanks ahead of time.

[micha3l]

Subscribed!

All I know is that I went on stock tyres with no supercharger and using Launch Control was useless, would spin on the spot, would be great if you could lower the revs more.

When just flooring it off the line, 60ft times were very average (2.0XX) but way better than launch control.

Next time I go I will have a VF620 installed and 305/30/19 RE-11's so hoping for some traction, but feel drag radials will be needed

[pkimM3r]

Feather the clutch. Oh wait ha.

Seriously though is it safe to launch the stock clutch with a supercharger? Will you be upgrading the discs?

[Longboarder]

Poor man's method (or otherwise termed "putting your foot through the floorboard") is very hard on the DCT. It is very effective in achieving top acceleration results for a stock M3 though. Slipping the clutch through launch control is much easier on the DCT.

With a S/C, the dynamics obviously change where traction becomes more difficult to achieve. Are you running street tires or DRs?

[The HACK]

Launch control will destroy your clutch. Mash and go will destroy your transmission. Pick your poison.

[Skooterbrah]

Originally Posted by Longboarder

Poor man's method (or otherwise termed "putting your foot through the floorboard") is very hard on the DCT. It is very effective in achieving top acceleration results for a stock M3 though. Slipping the clutch through launch control is much easier on the DCT.

With a S/C, the dynamics obviously change where traction becomes more difficult to achieve. Are you running street tires or DRs?

Hey longboardedr I've followed ya with your airstrip runs and all, so I know you're seasoned when it comes to boosted M's. Is there any proof of this? I was over at *********** with the same inquiry and i got this from over there.

from akh23456
"From my experience i did the "poor mans" launch a lot and barely used LC because of the stress is cause(5 times max).I actually broke the record for fastest ET doing the "poor mans" launch but it got broken by VAC later. I had over 300+ times at the 1/4 mile with my M when i had it. I recently sold it but my DCT felt the same from the day i bought it."

from LostMarine
"i know who is claiming what on LC and poor mans LC.. The same people have no experience other than this car, and have been seen doing things that should have blown the car up while at the track. oddly, they made it home, but not much longer all things equal, poormans LC will be less stressful on clutches, but possibly more stressful on other internals. imprtant because noone has had to replace anything besides clutches. the other question, is if it is more useful to do poor mans LC and real LC.
Currently, LC has shown better results for me, but thats because of tires used.. ill be testing this theory again shortly with even variables"

from Sticky
"Launch control is far more wear and tear. I used the clutches up in 10k miles due to it."

So it looks like once again im getting conflicting answers. They are saying over there that poor mans is less wear and tear compared to using factory LC.

[Longboarder]

Originally Posted by Skooterbrah

Hey longboardedr I've followed ya with your airstrip runs and all, so I know you're seasoned when it comes to boosted M's. Is there any proof of this? I was over at *********** with the same inquiry and i got this from over there.

from akh23456
"From my experience i did the "poor mans" launch a lot and barely used LC because of the stress is cause(5 times max).I actually broke the record for fastest ET doing the "poor mans" launch but it got broken by VAC later. I had over 300+ times at the 1/4 mile with my M when i had it. I recently sold it but my DCT felt the same from the day i bought it."

from LostMarine
"i know who is claiming what on LC and poor mans LC.. The same people have no experience other than this car, and have been seen doing things that should have blown the car up while at the track. oddly, they made it home, but not much longer all things equal, poormans LC will be less stressful on clutches, but possibly more stressful on other internals. imprtant because noone has had to replace anything besides clutches. the other question, is if it is more useful to do poor mans LC and real LC.
Currently, LC has shown better results for me, but thats because of tires used.. ill be testing this theory again shortly with even variables"

from Sticky
"Launch control is far more wear and tear. I used the clutches up in 10k miles due to it."

So it looks like once again im getting conflicting answers. They are saying over there that poor mans is less wear and tear compared to using factory LC.

IIRC there was some in-depth analysis posted in this forum in the Engine section a while back but I didn't subscribe to it, so it might be hard to find. Perhaps searching or posting in that section will help locate it. There are a couple guys like DLSJ5 and 1SICKM who would know better than I.

From what I remember, on a stock car, it seemed like either method would be ok for the car (not good but not something that would kill the DCT either); but once you increase torque levels substantially with the S/C, there is a lot more torque and therefore more load on the clutches...so either method is giong to be a lot harder and cause more wear. And again from what I remember, using LC was easier on the clutches vs the poor man's method with increased torque levels as LC allowed for a progressive "slipping" (i.e. less torque load) vs the entire torque onset from poor man's method. All of this is assuming DR's...as with street tires you are just going to spin anyway and that's not really hard on the DCT since the energy is being expended.

[JDM3]

If your car is properly setup with drag radials and linelock, your clutch and rear will be fine using launch control. I have hundreds of launches! Using the poor mans method, you can destroy your clutch and rear in one day!!! Anyone with a supercharger running the 1/4 mile not on drag radials....your waisting your time and risking your life !

Btw- all you guys doing burnouts with street tires at the strip, your waisting your rubber! The car won't hook any better as your tires are too stiff, sidewalls are too short and the compound is too hard.

[Skooterbrah]

Originally Posted by 1SICKM

If your car is properly setup with drag radials and linelock, your clutch and rear will be fine using launch control. I have hundreds of launches! Using the poor mans method, you can destroy your clutch and rear in one day!!! Anyone with a supercharger running the 1/4 mile not on drag radials....your waisting your time and risking your life !

Btw- all you guys doing burnouts with street tires at the strip, your waisting your rubber! The car won't hook any better as your tires are too stiff, sidewalls are too short and the compound is too hard.

Yea we are mounting 275/45/18 M&R radials for wednesday. How would a linelock effect launch? I know what they do, and how it would help with a burnout, but i'm not planning on doing one since im up in Colorado and my power is no where near the sea level 625 guys.

[JDM3]

Your not properly heating up your drag radials unless you do a burnout. You cannot brake torque the DCT trans so a linelock is a must!

[JABSprings]

Great thread. Subscribed.

Originally Posted by 1SICKM

Your not properly heating up your drag radials unless you do a burnout. You cannot brake torque the DCT trans so a linelock is a must!

Which company did you go with for the line lock?

[Morally Gray]

So how do you do a burnout? I plan to lower launch to 3500 with an ess tune, I read something about a burnout mode?

[AMPowerJ]

With stock tires it's a no win situation on the drag strip with a SC. I was all over the place trying to launch and go down the track with my 275 PSS tires. You need drag radials to have a chance at a proper launch. I trapped at 120mph and ran a 12.2 with a 2.2 60ft time and spinning through the first three gears.

[vettetom3]

I have a supercharged c6 vette that I take to the strip regularly, I am actually looking for a supercharged m3 right now so this thread is useful. It seems like some of you guys using launch control have the rpm's too high on the pre load and are blowing the tires off. When my car was stock and on street tires I put the car in manual shift mode and pre loaded to about 1500rpms and launched it that way. I'm wondering if this is an option on the m3's? Seems like that would eliminate some wheel spin.

[Someone?]

Originally Posted by 1SICKM

Your not properly heating up your drag radials unless you do a burnout. You cannot brake torque the DCT trans so a linelock is a must!

Originally Posted by Agent_Orange

So how do you do a burnout? I plan to lower launch to 3500 with an ess tune, I read something about a burnout mode?

I have a DCT and Drag Radials, how you heat up your tires without line lock with a DCT is you go through the water box, stop and with traction control off you floor it let it dump and burn out up to the line.
Works good , i get no spin my cars NA with a few mods and i go
1.85 60 ft
7.9=1/8 89.3mph
12.20@113.7

[Mr.Slow]

just use Launch control function that is already in there.

It won't engage clutch until you are ready to fly