efarley

I am having issues figuring out launch control on my c7. I have a '16 A8 Z51. Everything I have found says that I need to put the car in track, double tap traction control to enter and one of the 5 performance traction control modes, put the car in D or M1, hold the brake, floor the gas, it will rev to about 4k revs and hold there until I release the break.

What's happening though is I hold the break, push the gas and about 2.5 - 3k rpm the rear wheels start spinning and it wants to do a break stand burn out.

What am I doing wrong, or is my launch control broken? I swear it worked 5 months ago last time I used it.

only9balls

1) Put in track mode
2) Push button 2 times counting One one thousand, two one thousand, pressing on the one and two
3) You will see display tell you that you have entered performance mode, if you don't see that message in the display, it didn't work
4) Hold brake VERY HARD! Like a panic stop hard
5) Floor gas without hesitating
6) A8 will lurch a little then settle down to about 1800 RPM
7) Let off brake and hold on

If you lift the gas at any time, it will revert back to normal driving mode
I am not sure if it works in manual mode shifting, I haven't ever tried, I always use auto

My guess is you aren't pressing the brake hard enough.

efarley

So 1800 rpm seems wrong, the car will do that if I have TC on normal and it's a very laggy launch. When I've done it before and seen video online it settles the RPMs at around 4000 waiting for the launch.

As far as not holding the break hard enough, let's hope that launch control doesn't rely on the your breaks to hold the car until launch... That means it would fail 100% of the time if your breaks are worn or hot potentially causing a wreck or damage to the break system. I imagine they are using a trans break or something like that to lock the transmission until launch, not letting it apply torque to the breaks and hoping they hold.

only9balls

The A8 holds at just under 2k RPM, the M7 holds a lot higher. So, there isn't much forward push when staging, since the motor is only at 1800 or so RPM, so it isn't hard on your brakes at all. When you take your foot off the brake pedal, and leave the gas floored, that is when the magic happens, and the car accelerates as fast as possible with the least amount of wheelspin it can manage.

Here is a video of me doing it... Notice the throttle position, and the RPM's...

efarley

Interesting, that's how mine behaves IF I leave traction control on. Going into performance shift mode let's it rev past that which causes the wheel spin

markcz

You need to stomp the gas to the floor quickly, don't just slowly push it down. Then once moving, just leave it floored.

efarley

Stomping on the gas seemed to be the trick.

Maxie2U

Can I assume these instruction also apply to a non Z51 too?

only9balls

Yes!

only9balls

I mentioned that in #5

big red one

thanks for posting the video by the way

River Rat

When LC is done correctly, is there any wheel spin or slip or audible tire gripping sound?

It feels like my A8 is leaving in 2nd gear. After it gets going its a beast but the initial launch seems a bit delayed from what I'm used to. Shouldn't the computer struggle to keep the car from spinning? Some chirping, something?

efarley

That's how mine behaves if I don't have traction control in performance mode. It will have some wheel spin when done correctly

kenownr

Mine works fine when I finely realized:

Hold the brake down really hard

Stomp hard (quickly) on the gas till it's floored. (disregard the slight lurch)

Settles in at about 1800/1900.

I was just letting up on the brake quickly and getting 4.0/4.3 zero to- 60's on the PDR.

A friend of mine (expert racer) told me to try holding the brake with the inside edge of my left foot, on the lower left corner of the brake pedal; then pop my foot off down and left. Got a couple 3.8's and a 3.9. A tenth is a tenth LOL

markcz

Not as much as you would think. Wheels slipping/chirping/squealing means they aren't gripping, the computer keeps them at max traction.

efarley

Here's another video that shows it better. Both on auto and manual. He also talks about the wheel spin.

only9balls

If the tires and/or road is cold, they will slip a little bit (mine don't chrip I think they are too soft for that), but if the road is warm and sticky and the tires are warm ,you usually won't hear or feel any slip. At the track there is none. My normal 0-60 with launch control is 3.8 (with just me in hte car).

only9balls

You are welcome!

9t6t7

If starting launch control in M1 will the transmission shift on its own??????

lakemg

Thanks for the video...how did your actual time slip compare to the PDR's measured value? I was just wondering how accurate the on board performance timer is.