what happens if you dump the clutch?

[nextcar]

Hi, I've had my 2008.5 ms3 for over a year now. I've never dumped the clutch. In all the car magazines, when they do acceleration tests, they usually rev the engine to a high RPM, then dump the clutch for the launch. Then I assume the tires are spinning, and you have to modulate the gas pedal for the tires to stick.

I feel a bit nervous about doing this, so I thought I'd ask you guys. I know I've read here that to get the best launch, we should let the clutch out more gradually. But what would happen in these scenarios:

1. rev to 3000 rpm, then dump clutch, or
2. rev to 5000 rpm, then dump clutch.

Would the results be any different with DSC on or off?

My car is bone stock.

 

[coyfish]

Well a higher rpm launch is obviosly a more aggressive one. If you are bone stock I doubt you need to rev past 3500 to launch. Anything more is just going to cause excess wheel spin.

You should turn DSC off when your going to launch. Once your car loses traction the ECU will cut power / etc. to compensate.

As for modulating the gas pedal. There are launch controls available for the speed's like the cobb ap's new launch control of a 2step wotbox. To manually do it, it just takes practice. I rev it to 3500 and let my clutch out briskly but not too fast while increasing the gas. Once the clutch is out I hit WOT. Of course i have the speed 6 which is different due to the AWD.

Launching is, as you can imagine, hard on your clutch, tranny, and drivetrain. That is why it is recommended to purchase supporting mods like engine mounts, shifter bushings, springs . . . etc. The more you launch the more wear you put on your clutch which shortens its life.

 

[carbosam]

I rev it to 3500 and let my clutch out briskly but not too fast while increasing the gas. Once the clutch is out I hit WOT. .

Ive gotten pretty damn good at lauching now, what i do is about that...with the MS3, you gotta let clutch go a little slowler and i personnaly rev only at 3000-3200 to avoid to much lost in traction

Dumping the clutch is completly unecessary

 

[bigdaddy]

our car is fast enough. just do highway pulls. or just roll off, then jam the gas, hard to focus on the rpm's, but whatever

 

[MSMS3]

Even as low as 3,000 rpm, a clutch dump followed by full throttle will roast the tires. Even partial throttle feathering is difficult to try to get hooked up without bogging is difficult for me. And you need to be quick on the draw getting the shift to second, because with our very close ratio 6 speed tranny's gearing, a hard launch has you in first gear less than two seconds (about 1.8), with a good launch and even less, if the tires go up in smoke.

With everything going right, I can get to 60 mph in around 5.1 seconds. but I'm still having trouble despite a lot of practice and launching as low as 2000-2200 rpm, getting the first 60 feet of the launch under 2.2 seconds. This is where races are won and lost at the drag strip. My 2.3 second 60 ft times are not very good.

So, a 5,000 rpm launch on stock tires is an absolute waste of time and effort. You'll never see any traction at all and hit the rev limiter almost instantly.

 

[8.5MS3]

broken gear teeth

 

[Anna-chan]

Launching the car is not that tricky. Rev to about 2500, DSC off, feather the clutch and youll get a tiny bit of spin, it will hook, and off you go.

This does not work if you are fully bolted pushing 22 psi on R compounds. Spin city ftw!!

 

[eg6motion]

broken gear teeth

not unless you do it all the time, abuse the tranny, WOT shift or all of the above.

 

[8.5MS3]

not unless you do it all the time, abuse the tranny, WOT shift or all of the above.

well he said dump the clutch = abuse

i really wanted to say - you go into a gear

OP - nothing over 2500 rpm, 3k and your spinning tires, doing big damage @ 5k and your picking up metal pieces off the street....this aint no subie

 

[Agent 00 L]

If you just dump the clutch the tires are just gonna spin and spin. Nice for the show not so much for the go.

For a decient launch I hold the rpms about 3k or so and then feed the clutch out quickly but don't dump while giving it gas. Be ready to grab 2nd real quick, normal quick shift here off the gas the normal way. After you get into 2nd keep the gas floored for the rest of your acceleration run. Quick shifts the rest of the way keeping your foot on the floor. The drive by wire throttle on these cars is really slow to go back to WOT after you lift between shifts. Flat shifting is worth at least .3 or more for a 1/4 mile.

Now if you dump the clutch at 4-5k on a tire at the drag strip, now that breaks transmission mounts.

 

[H3br3w_Ham3r]

Wheelspin

 

[onelsono]

If you just dump the clutch the tires are just gonna spin and spin. Nice for the show not so much for the go.

For a decient launch I hold the rpms about 3k or so and then feed the clutch out quickly but don't dump while giving it gas. Be ready to grab 2nd real quick, normal quick shift here off the gas the normal way. After you get into 2nd keep the gas floored for the rest of your acceleration run. Quick shifts the rest of the way keeping your foot on the floor. The drive by wire throttle on these cars is really slow to go back to WOT after you lift between shifts. Flat shifting is worth at least .3 or more for a 1/4 mile.

Now if you dump the clutch at 4-5k on a tire at the drag strip, now that breaks transmission mounts.

i wouldnt ffs a car unless it was tuned to do so. doing all this stuff without having the stuff to support it is like asking to break. its a fwd, put it in 2nd and go from a 30.

 

[nextcar]

thanks for the responses.
so i think i'll try to rev to 2000 to 3000, and let the clutch out fast, but not dumping.
what is meant by feathering the clutch? slowly releasing clutch?

if i keep the DSC on, then would it completely keep the wheels from spinning? is it kinda like the computer reducing the gas so that the tires will gain traction faster?

 

[onelsono]

thanks for the responses.
so i think i'll try to rev to 2000 to 3000, and let the clutch out fast, but not dumping.
what is meant by feathering the clutch? slowly releasing clutch?

if i keep the DSC on, then would it completely keep the wheels from spinning? is it kinda like the computer reducing the gas so that the tires will gain traction faster?

if u keep it on the car will just loose power when it begins to spin, u need to have it off to launch

 

[jnr5005]

DSC on allows for consistent, and quick launches on street tires. Just slip/feather the clutch a little.

 

[Stotrupp]

When I use to go to the drag strip I constantly nailed 2.0 -2.1 60ft times on street tires.

Method: Hold approx 2500rpm and slip the clutch quick while modulating the throttle to limit wheel spin. Launching higher than say 2800rpms will just result in catastrophic wheel hop and a poor 60ft unless you’re on slicks/ radials. Remember this car makes 280ft-lb Torque@3000rpms which is pretty damn high for a relatively light FWD car.

My fastest 0-60 time is 5.2sec with Cobb sri as only power mod according to dashhawk. Time to distance I'm sure isn't 100% accurate due to wheelspin but time to MPH I don't see why it could be far off unless you make so much power you're spinning at 60mph.

 

[SgtP]

this thread is awesome.

 

[hectik1]

Commence smoke screen!(inout)

 

[MikeHTally]

Dump the clutch, car no move. The clutch is necessary to connect the engine to the tranny. (drive) If you remove that link, car no workee.

 

[Speed3B]

Anyone that "launches" with traction control on is just a silly billy.

Get out on the street and WOT all the way up to the limit with "DSC" on
now
Do the same thing with "DSC" off.

Its not a huge difference but the traction control nanny is always taking a little bit away from you.

That said, when you hit "DSC Off" you arent turning off DSC but only traction control. Unless you are AutoX then just turn off the traction control.