[pf C4S]

I went to a track event at Autobahn in Joliet on Monday, Il with the PCA (that was excellent!)...

After each run (30 minutes) we had about 1 hour break... when I started the car again there was white smoke for a couple of seconds... I would say white but with the dark windows I may be wrong on the smoke color...

Then I drove back home (about 2 hours) and this morning it was back to normal (no smoke) when I started it...
It did that to me some time ago after intensive use but then back to normal the next day...

My car is a 2002 carrera 4S with 27000 miles. The only thing I have is a KN filter...
I checked coolant level, no pb.
I checked oil level, no pb.
I checked the oil tube, no "marmelade/mayo" inside...

Could it be "just" because of the fact it has been pushed to its limit for half hour runs (well I should take that back... the pilot was pushed to his limit... the car was just pushed a little!!!) ???

Any idea about this issue???? is this "normal"???

Thanks