What is the "normal" temp for PCCB disks after 20min track session and a two min. cool down lap during which no brake was applied??
My disks were running at a lofty 450-455F at all corners. Very consistent, after each session. Is that normal?

 

What track, pads and tires?

Temperature varies by driver, track and tires.

455 F is not that hot for hard track use. I would start worrying at about 550-600 C.

Great way to tell is to apply thermal paint on the rotor cheek and vane. As the disk temperatures go up, the paints oxidize allowing you to see the rotor cheek and vane core temperatures. If the Red paint starts turning white at the edges...it's getting pretty hot. I would keep keep an eye and start measuring rotor and pad wear at that point.

 

I used to get the rotors on my 944 Turbo S to glow Orange which I think happens close to 1,000F, so I think you have barely warmed those PCCB's up

 

Totally normal. I posted some time ago about the rear duct retrofit experiment where I had one side with a duct and one without. The rear with the duct was just below 400, the one without was above 500. Those puppies at the end of a huge brake zone have to near 1000.

 

There's a lot of room for error in masuring rotor temps, but that doesn't appear top be very hot at all.

I got several readings in the mid 750Fs at WGI from a 997S 3.8 w/ steel rotors

 

I would be more concerned about the temp of the calipers. The O-Rings (inner pressure seals) are rated for a max of 398 F. Above that temp the (EDPM) seals will begin to lose their elasticity and their durometer changes. This will affect things like how well the pistons retract following extension and how well the O-Rings wil seal. The PCCB rotors should be good for 1400 - 1800 F without difficultly but the caliper can't take that level of sustained heat.

Pick up some of the rotor temp paint & caliper temp indicator strips (avail from Pegasus Auto Racing, BimmerWorld, Truechoice and others) and you will be able to determine where your calipers/rotors are running.

HTH