This is going to sound idiotic but over the last couple of years I have been collecting S5 NA rotors but I believe I still had 1 REW rotor and now I have the them mixed up. Any help identifying the FD rotor if there is one among the S5 NA rotors? Tried measuring combustion bowels to apex edge and to side seal edge and they all appear the same.

 

Try liquid displacement?

 

would any stampings on the sides have any indication?

 

OK, figured it out. The combustion bowel on the FD is .110 deeper than the S5 NA This measurement was made at the apex of the rotor curve.

 

I know on fc turbo rotors there is a T stamped next to the bearing on the non gear side. Non turbo rotors do not have it. First one is a s4 turbo, next is a s5 na

 

Didn't find a T on my rew rotor.