I know 64pitch, but the size of the pinion/spur will affect the motor's efficiency slightly.
maybe you can try a larger spur, like a 96 or even 100.
(usually a smaller spur requires the motor to work more, thus using more current on your battery)
Also, are you using turbo/boost function on your sp2.1?
1cell with 4T is superhot too.. which 2 cell you're using...
Actually I have 2 x 12仔: 1 link and 1 t-bar
1. link car I am using 2xA123 + 10.5 + boost
2. t-bar I am using BY energy softpack, 4500/25c. (I have to raise the battery 3-4mm to clear the t-bar in the middle)
If you have the link car, most c-hing will use 1/18 2s 1800mah battery to play.