6s Lipo on a Feigao 8xl?? help pls

Is 6s Lipo too much voltage for a Feigao 8xl motor?

I have a MGM compro 16018 on the way, as well as two 3s 4000HV lipo packs. When I was using BrainG's parameter calculator, it came up saying 22.2 volts exceeded the 40000 rpm limit of the 8xl motor, and overheating would result.

Since the unloaded kv rating is 1875kv x 22.2v = 41625 rpm.

Is that calculation correct??

Is this the unloaded kv? (Calculator says 2084kv, but the rc-monster store says 1875kv)

If it is then it's not that much over the rated rpm of the motor. Would this still produce too much heat? Will a fan help any?

But then what is the loaded kv rating?? Wouldn't it be lower? If so then the rpm's might be within the motor's rated rpm limit?

I know thats alot of questions I asked, but I'm really confused!
Any help or knowledge here would be much appreciated!!