brushless losi 8b

[FG101C]

Any ideas why my Medusa 36-70-1600kv motor got hot running 5s geared 14/45 in a Losi 8B. It ran awesome on 4s geared 16/45 and cool but wanted to try 5s to get a little more speed. I know the Losi 8ight diff ring and pinions are 40/13, and with that 45 tooth spur is why I think things get hot easy in this buggy.

I was running a NEU 1512/2.5/D/F (2050kv) on 4s but it got hot, over 175, on any gearing combo from 10/45 all they way to 16/45. All the typical things are ok, drivetrain is free, nothing hangs up. The only main difference I seem to notice is the majority of people on here don't run on a track in race conditions. Speed runs in a parking lot are not going to heat up the motor like running on a track will. I've only ever driven it on the track. There's no way I could run the 2650kv motor, would hit 200 in 5 minutes. Maybe my driving style needs work.

Any ideas or suggestion are greatly appreciated. Thanks.