sjfehr

I did a test & tune at a local dragstrip Friday for my daughter and I to practice for the upcoming Bristol ProSolo. Its been a few years since I've practiced my launches (and she has never done it), so was good time spent. This was the first since I figured out the right button combo to do a burnout after driving through the water box (important for not launching wet, lol).

I learned last time I visited the drag strip that there is a 1.5 mile lockout for first-gen (987/997) PDK launch control. The first launch will do the magic clutch-slipping perfect launch; the second will give no visual indication to the driver that anything is amiss and will happily rev to 6700rpm and make you think you're going to do a launch, but PDK will instead just dump the clutch when you release the brake, and you'll either immediately have traction control kill the throttle and re-launch from idle, or leave you going nowhere in a cloud of smoke if you're in Sport+ with PSM off. Both options suck; the only recourse is to drive around for 1.5 miles before launching again, which is not possible in a ProSolo.
I got some pretty good data from multiple launches at the dragstrip, and I thought I'd share as there are a lot of people here interested in this stuff and it's really good data. I got slower every run as the night went on, but I neglected to monitor either tire or intake temps, so I'm not sure if it's due to tire temp, heat soak, or both.

The blue trace was intended to be a full 6700rpm launch but the tree dropped while the RPM was still building and I released early. Got a pretty good launch out of it anyway - and verified with the next sloppy run (green trace) that it trigged the lock-out.


Note: All runs in ProSolo prep & more or less ProSolo pressures. I kept accelerating past the 1/8 mile point as I wasn't sure precisely where the end beams were, so just kept on throttle until I passed the boards; the cursor is marking the appx actual trap point.

Anyone discovered any way around the 1.5 mile lockout for ProSolo? Seems as though it improves 60' times by about 0.3 seconds, but significantly increases the risk of redlighting due to the different reaction times and needing to launch at different spots on the tree. If launch control is only available the first launch of a session, I honestly think I'm personally better off eschewing it completely and just launching from idle for more consistent launches through the weekend, which will also help manage tire heat (important for RT660 & A052).

Video of Run 3 (blue trace) which turned out to be my quickest 1/8 mile of the evening. Ted Collier's CAM-C prep GT350R is in the other lane. We both had abysmal reaction times that run, and he had a bad launch but still trapped 10mph faster. He smoked me far worse the other runs, lol.

cmorales954

Reviving an old thread to add some info. about other Launch Control (LC) interventions that may exist.

I, and another PDK LC-capable car, were experiencing bogging milliseconds after a LC start at a recent autocross, and it was bothering me trying to trace the issue. Some suggested PDK temps, or perhaps too much grip causing PDK to protect itself (I was on fresh A052s)

But, some post-event testing I did confirms: if you have to provide any meaningful steering input immediately after launching using LC (e.g., within what feels like a second or less after launch), PDK LC will pull throttle. This still happens even if you have stability/tc off, as LC forces the car to have this on momentarily.

Video of my bog here (excuse the first throttle depress -- this was to put the DSC controller into its LC mode):