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-   -   Launching Consistently - Whats the Secret Sauce? (https://rennlist.com/forums/991-turbo/1060776-launching-consistently-whats-the-secret-sauce.html)

dsddcd 03-31-2018 09:49 PM

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?

swoobie 04-01-2018 12:47 AM

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

Steve Cole 04-01-2018 10:48 AM

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.

Randyc151 04-03-2018 10:58 AM

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.

Need4S 04-03-2018 12:35 PM

Do you need Sport+ mode or just Sport?

Randyc151 04-03-2018 12:38 PM


Originally Posted by Need4S (Post 14915687)
Do you need Sport+ mode or just Sport?

Sport+


Steve Cole 04-03-2018 07:24 PM

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.

Vrrooom 04-04-2018 10:00 AM

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.

Randyc151 04-04-2018 11:10 AM

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.

dsddcd 04-06-2018 06:47 PM


Originally Posted by Vrrooom (Post 14917709)
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 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!

Randyc151 04-06-2018 07:10 PM

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.

dsddcd 04-24-2018 11:03 AM

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!

dsddcd 10-24-2018 12:19 AM

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.


Jeff Kay 10-24-2018 12:34 AM

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

neil.schneider 10-24-2018 12:34 AM

I have done launch control many times in my car. I always use the method as shown in the video above. Sports +, and then left foot on the brake and right foot full throttle. I did 11.05 at 124.1mph. I did get a little bit of wheel spin and I was going up a slight incline. I now in the right conditions I could definitely do better. Also, I have a cabriolet and had 3/4 of a tank of gas.


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