Number of cells a 4400kv can handle?

[Rtsbasic]

I have a new motor next to me sold by Mtroniks called the "Sport Plus" motor with a kv of 4400. Its a 480 motor and I think made by Feigao (looks exactly like a Feigao from the outside with a Mtroniks sticker), I was wondering, if it is a rebadged Feigao, how many cells would it be OK to run a motor of this kv on? Mtroniks say 7 cells, but they waaay underrate the volts their controllers can do as well (my genesis pro controller on their site says can do 8 cell, I phone them up and find out it can actually do as many as the truck esc (12)). Curious if its likely to explode if I take it up to 50-60k RPM if its a Feigao motor..

Thanks guys