Odd sound at the track today

[pilot4fn]

Cheers all chaps with buch of Boxster 986 knowledge here!

Today was the first track day for this year at the KymiRing Finland. It was a rainy day, but a whole lot of fun with my 2001 Boxster 986 2.7 with Manual transmission.

After driving 5 laps, on a fairly tight lefthander the car gave up a NOT very loud grinding-shaking-rattle for a moment and it sounded coming from right side (both, me and co-driver felt the sound to come from same direction), but we're not certain if it really came from rear while it kind of sounded like that. I continued the lap to end a bit slowler speed and went for the pits. Could not find anything loose or out of place while inspecting the car.

Waited our next heat approximately 45 minutes. Same thing happened again exactly same way. Just like some part had to get warmed up before giving up the noice. Inspected again at the pits and have no any idea what this could have been. Had to try again third time and same saga continued exactly same way.

Car drives otherwise real well, while I could feel the tired two suspension parts (rest of the front and rear parts were replaced last August):

- 996 341 053 07 Wishbone (Coffin Arm?)

- 996 331 045 12 Track rod

And, to make this even more strange investigation work, after the day at the track, I drove home for 120 km and I could not find anything wrong with the car on the road conditions.

Would you have any ideas where this wierd and difficult to describe noice could come from? Could the old Wishbone and Track rod give too much play to cause driveshaft joints to make noice after being warmed up or maybe the rear bearing is giving up and acting up when it warms up or completely somethign different causing this? Last September I drove the previous track day with no any issues and car sat thru the winter. I have used the car almost as a daily driver during last 1,5 months.

All help and possible causes for this noice would be most welcomed.