Let me guess, it was a 20x30mm 7850Kv motor? If so you would have seen more speed and punch, and it would probably still be running if you used a 13-14T pinion rather than the 18T. For the Castle CM2646, on 2s lipo in a RC18, 18T should just get it up to normal operating temp and run there all day long without any worry of heat.
This is Hell, Dante. Not your personal fantasy.