[pinkpanda3310]

Your question is a little broad. What kv motor, esc, gearing and battery? What do you want to do with it? race, bash, speed runs?

As a rule of thumb, if you gear to the same speed, higher voltage = lower temps, but that also depends on the motor.

With a good motor you should aim for 30k-40k revs on the voltage you want to run.

When deciding on a set up, your battery should be the first decision (volts and continuous amps) and then an esc and motor to suit. Then gear it right with BrianG's calculator.

If you stick 6s in your current set up I would imagine it will go like a bat-out-o-hell, get high temps and fry something.....but then I don't know your setup either. Can the esc and motor handle more volts?