On 4s the motor is fine. However, if all you want to run is around 40-45mph, there are much better choices that will be more efficient and yield better run times. The 1.5d is very hard on the ESC and batteries. If you want to run 4s I would recommend the 1512 2.5d (2050kv) and just gear it up for the speed you want. It will run almost twice as long as the 1.5d. Or better yet, run the 2.5d on 5s or 6s.

Brian;

To run 3s, you really need a 8000mah pack. That motor was just to amp hungry and the 6000 pack was straining. My packs would come off the track after 10 minutes of racing at 125-140 degrees.