FPFaeth

Today was my first track day with my 2015 911 GTS (bought last December with very low miles). On Pirelli PZeros, the car's behavior in corners was unstable, with the tires giving way and giving a general feeling of them being greasy. I played with the tire pressures (were 34/40 before each run and 40/50 at the end of each run). I have a fair amount of track time with a variety of cars and, most recently, a new Corvette Z06, and knew the GTS would handle differently. Does anyone have tire pressure suggestions? I know I will need to replace the Pirellis. Any guidance would be appreciated. Thank you Frank