I finally got the FD to the track, and after a 20-minute session, we are hearing a slight metallic-rub that is coming from the cooling system, most prominent on the nut at 12-o'clock of the RE-Medy water-pump pulley (use used a long screw-driver touched various parts and placed our ears on the screw-driver handle).

After a 30-minute cool-down, it goes away.

It is INTERMITTANT with no set pattern, or cyclical rhythm.

We were thinking the pump impeller might get lose at high-temps, but then it would be cyclical noise, which it isn't ?

Any other ideas ?

Thanks,
:-) neil

FWIW, with the OLD water-pump, typically water temps would be closer to 220-F at the track; with the RE-Medy water-pump, it's been a steady 210-F running 14-lbs of boost on a mild-street port, with stock turbos 4x850cc injectors, and stock airbox, and SMIC.

 

Update: it was a faulty thermostat. All is better now!