Launching Consistently - Whats the Secret Sauce?
 

So I would like to take the car down the strip for fun in an upcoming event. So I went out today and tried a few launches, figured I would be able to just hold the brake, gas and go but it appears its not quite as easy as a Tesla ;-) It is still chilly here, roughly 60F, and the car spins a bit but there are a few things I am trying to figure out.

1.) Launch with PSM or without?
2.) Best Way to Prevent Short Shifting?
3.) I am getting a bit of hesitation with the PSM on and Off in first at say 6,500 RPM where the car loses all power for a split second then comes back on revs out and shifts, is there a way to prevent this?

I'm sure there are people who can add a bit more, but these are my keys:

1. Make sure the car is completely warmed up - coolant and oil temps
2. Sport + with PSM off
3. Rev to 5600, with left foot on brake
4. Release left foot and hold on

I put it in Sport mode, drive up to the line, fully warmed, and then push the Sport Response button. I keep the aero down, it will kill some of the trap speed / e.t.

All of the above, but left foot on the brake, then press the gas pedal assertively, not gently. This tells the car you mean business, and it will take that message and comply with launch mode.

Sport+

Sport+ puts up the aero, and that will slow your car slightly. If you're going to use Sport+, either put down the aero or use it in I mode to set it up. Also, PDCC stiff mode may or may not work for you, I turn it off to get more transfer to the rear (or at least, that's my theory). Which is why I don't bother and just pull up to the line, wait for the tree and hit Sport Response. I don't care about whether my reaction time is good or not, really but if I do try to get a better RT then I put the car into LC and again hit the SR button as soon as the tree starts.

You don't need to be in Sport+ to use launch control with the 991.2.

I have a 991.1, so I put it in Sport+, hit the aero to retract it, switch chassis back to normal and then go. Recommended tire pressure is a little high, so I drop it to about 30.

More on your questions:
1- I don't turn off any of the traction aids as even when the car spins I don't see any intrusion on it. I think its pretty lenient on launch control and even the 1-2 shift sometimes gets sideways and it doesn't intervene.
2- Sport+ does a good job of shifting where it needs to, however I prefer the paddles and manually shifting, read 3 as to why
3- I experience this occasionally too; best I can tell it is when the car spins and perhaps the wheel spin hits the rev limiter prior to the shift. I shift manually to prevent this and if I feel excessive wheel spin I short shift into 2nd (around 6k). The shift usually helps with traction and the crazy torque keeps the car moving pretty quick. Doing this the car doesn't cut power like you mentioned. It also only happens on the 1-2. It could be something else entirely but I'm pretty certain it is wheel spin related and tied to the rev limiter prior to shifting.

Anyone else's insight on 3 would be great.

I've found the car does better than I can do under every circumstance. Paddles for me have shown to be slower, the aero makes no difference at these speeds (it's actually more looks than downforce) and when the car cuts power...it knows what it is doing.

I was getting lots of wheel slip, it started by short shifting then I got a little more heat in the tire and it started hesitating. I think it is traction control though I have had this happen in other cars when they hit the boost cutout. Since I am stock but only have 91oct this was a second guess. I might try again then if it does not work put some Torco in and try again. Snow moved back in here in the midwest so I will have to wait to try again.

Thank you all for you help!

In launch mode, the car will use TC as a means to reduce wheel spin, and it's better at it than you are. Without TC, try to launch the car and see how far in the woods you end up. Following the procedure in the video above is the best way. There's little/no benefit to aero up/down, shifting it yourself, or really anything else except giving the car nice warm tires and a clean patch of pavement.

Thank you all for your advice, I finally got a chance to get the car out with warmer weather and tried (2) launches last night. They were perfect, still a bit cool so there was some wheel slip but the car launched like a bat out of hell!

Back from the dead, I found this from some video of One Lap 2018. I was able to catch the "Missed" shift between 1st & 2nd. The car ran 11.1 @ 124 mph but the other stock Turbo S, 991.2, went 10.7 @ 127 mph. This was the last time this happened so I never did find the underlying cause.

I found that leaving psm on and NOT put it into sport pasm

first pass ever with launch control , left in auto , Sport + , cut a 1.54 60ft with a tiny bit of spin, this is on stock tires , stage 2 93 octane tune and Kline catless exhaust. 10.42 @ 131.6 . not bad for it's first go .

Some info about launching.

You deep staged by at least 6", your car is already rolling when the stage light is already set (easy to catch by the gateway challenge lettering on the center divider). Once you pre-stage, take your slow time to set to stage, especially when your pair (looks like Andy Hollis's car) is already staged (meaning it has an advantage on concentration and attention to the lights). Every 1/2 foot deep staged cost 0.1 on the 1/4 mile. Your car may have cut an 11.0 @ 125mph with proper staging. For the souls comparing these results to their best attempts, consider that One Lap of America is run on not the ideal prep surface, it is not ATCO Raceway were all the E.T. 1/4 mile times are so optimistic, the OLOA drivers are not on 116 octane fuel or 40 degrees weather, but they all run in the same conditions, and their collective results are more meaningful that one-of-a-kind maganize/youtube tests.

Then comes another factor, that 1st-2nd gear early shift may have cost another 1mph on the 1/4, but not a difference on ET. Considering that a stock 991.2 Turbo S has close to 40hp over a 991.1 Turbo S, those times look right.

I have launched the RS and TTS on competitive events, using 2 telemetry systems (and sometimes 3): Solo DL+SC, VBox Sport+HLT and in the RS the Porsche Track App. LC is awesome but the literature is poor as to explain how it works.

1) Regardless of being in manual mode or automatic mode for the PDK, if the dashboard reads LC enabled, the 1st/2nd upshift happens automatically
2) Depending on surface the car can early shift to 2nd, or bounce the rev limiter in 1st before going to 2nd (in my case, my car has gone 1st/2nd/3rd/2nd on LC)
3) In the TTS: :LC works with PDCC on/off, PSM on/off. Despite of the shock settings, LC soften all the compression on the rear shocks and stiffen the front for max compression, the shocks go back to their sport/comfort mode once the car touches 2nd gear. On low grip surfaces (where the car will still spin 4 tires in 2nd gear), launch in soft mode produces better acceleration numbers
3) Sport+ activates the performance aero, but these cars don't generate massive downforce. The 991.1 Turbo S with the spoilers in maximum downforce generates a little over 130 lbs of downforce at 125mph (and close to 300 lbs at 186mph), generally for 1/4 mile passes, the spoilers in low drag mode performs better, but the difference is too small. On a 1/2 mile or 1-mile long run, the difference would be sizeable. (My RS produce almost 3 times the downforce of my TTS at high speeds).
4) With the Cobb-PDK tune, and the agressive torque program, when launching in manual mode, LC holds the gears, I have had my best launches on street pavement (no drag strips, but regular pavement) with the Cobb-PDK, cutting multiple 0-60 mph in the low 2.42-2.45 secs on full pressure (38psi front 48 psi rear) MPS4S tires. The Cobb-PDK tune uses a soft LC for comfort mode, and an enhanced LC for sport or sport+, whereas the stock PDK tune uses one LC program for all the modes.

The enemy of the 991 Turbo S is weight. most cars are in the 3,500-3,600 lbs weight before driver (add plenty more for cabrios). My TTS is super light, 3380 lbs on low fuel.

You called it that was from OLOA 2018, and we did indeed run stock class with what ever fuel we could find. The car was on 4's with NO spec with full interior. We still finished the drag race a second behind Mike's 991.2 Turbo S but it still frustrates me that it was hitting the rev limiter but it was not consistent. So the next run was a bracket run and I had to dial in against the 991.2!. Of course it shifted perfectly and I had to let off at the end so not to break out. Per you details above it appears that touching the rev limiter is fairly common so I will chalk it up to a fluke.

My best results were first dump the Pirelli tires, I switched to Michelin PSS and much better traction in all conditions, the Pirelli's would just spin. I use sport mode, left foot brake, push the little red button in the center of the sport control and push the gas to the floor and release the brake, with stage 4 from Sam at By Design the fun never ends