DG80

Hey all,

I did some research trying to find a post that covered this topic but couldn’t find anything specific.

When activating launch control and turning off traction control, does anyone know if there are still nannies engaged? Reason being, I was messing around with it the other day and, even with traction control “OFF” the car seemed to bog a bit when I released the brake to launch. Like it cut fuel or something…

Now, I don’t expect (and wouldn’t want) a clutch side step effect as that’s how you break stuff but I’d think I’d get more of a clutch slip and wheel spin than I do. There’s almost no difference between leaving the TC on and off.

Is there a setting I’m missing or is that just how these cars always behave in that scenario?

Step 1) Sport Plus mode “ON”
Step 2) Traction control “OFF” (“PSM Off” displays)
Step 3) Apply brake and mash throttle
Step 4) Release brake and go!

Any insights are appreciated.

desmotesta

I never had to turn PSM off to activate launch control in my PDK car

DG80

I don’t have to turn it off. I’m saying turning it off doesn’t seem to make a difference. It still bogs down, like fuel is being cut, when I launch with TC off.

desmotesta

Ah ok.
From what I remember, if the road conditions were bad or tires were very cold, even if Launch control was activated, the car would bog down. It worked best in better road conditions and warmed up tires

asellus

There was a thread on this last year. Let me try to dig it up.

asellus

Nevermind, I misremembered. It was someone trying to abuse their manual transmission and wondering why problems were happening. Whoops.

Between steps 3 and 4 you should have "MFD says Launch Control Active" -- you're getting this message, right? Stepping back a little, does the car have sport chrono?

The few times I've done the LC gimmick in my 991.2 I've had PSM on sport, not off completely. It was on warm pavement with summer tires, no noteworthy wheel slip or TCS blinking. Letting go of the brake resulted in an airplane takeoff style consistent acceleration feeling, which makes sense because it slips the hell out of the clutch.

DG80

Thanks for looking! Yes, it does flash "MFD says Launch Control Active" and, yes, I have sport chrono.

I've had a few times, in the past, when it felt kind of like an airplane takeoff with a good clutch slip. Just threw some headers on the car and tried to launch it yesterday but got the aforementioned "bog" feeling rather than a clutch slip... Also, kind of expected the tires to spin a bit but, again, it almost feels like TC is still active given the bog down that feels, to me, like a fuel cut to prevent slippage. Just seems like TC isn't all the way off - Quite odd.

asellus

This is one of the other threads from last year, not necessarily about launching, but about bogging on a PDK.

https://rennlist.com/forums/991/1256...-behavior.html

DG80

Interesting - Thanks for sharing. I don't have that issue, fortunately. Just the launch control situation.

Al.Fresco

Car needs to be fully warmed up.

I’m guessing you are not keeping foot mashed on accelerator past the click down position upon launching. Any letup, ever so slight, on the accelerator will result in your bogging issue.

DG80

Pretty sure I had it pinned to the floor. Will try it again to ensure that's the case!

chipmunkchan

This. You need to step on the pedal all the way to the floor. You'll feel a click once you do so, and "Launch Control Ready" or something like that will display. If you do not lift off the brake after a few seconds, the launch control will deactivate on its own.

asellus

The 991.1s have a mechanical kickdown switch in the throttle pedal? The 991.2 (or at least, my 991.2) does not.

DG80

I don’t know about feeling a click but the Launch Control Ready does display and, of course, the RPMs shoot up to around 5k.

AdamSanta85

In my experience, the 2S gets out of the hole better with PSM off + Launch Control. A small bit of spin and then it hooks and goes.

I've had it bog with PSM on.

OP I wouldn't expect too much wheel spin or anything in a .1 4S, AWD + somewhat low torque.