If when you are referring to this 3300 motor, it means that it is rated at 3300kv, this equates to a 13.5 turn motor, according to Novak's brushless motor chart on their website. This would be an illegal motor in a 17.5 spec class. I looked around last year for a 2200kv rated sensorless brushless motor and could not find one, and I became aware that high turn sensored motors, like 17.5, generally exhibit lots of cogging at low speeds with an unsensored esc. I used brushed, untill I finally purchased an sensored esc and motor combo.