I will add that I have _punnished_ the Porterfield R4 pads and still had the ability to slow the car. Smoke pouring from the wheel wells, quite literally, and still had brakes. Not to say they didn't fade, they did. But they didn't go away either.
Yes, it was deliberate.
And I've run high performance street pads on the track (with no ducting) and they went AWAY after one or two laps. yes, they were GONE.
I won't ever do that again... Not fun...
-Josh2