Cabking;
I am running a hyper 7 on an 8XL with 4s li ion (pretty close in Voltage to li po).

I have been testing for a few weeks.
Running 13/44 gearing. Speed I would guess around 30 MPH
Race conditions tests for 10 min races.
Motor requires a FAN to stay with the 150 F With a fan the motor is fine.
The weak link is the 9920 gets hot.
Run times on a 6000 MAH battery is unknow. I ran 45 min yesterday (with pit stops and cool down periods) and it only used 4500 mah.

If I were to do it over again I would get a 9XL 5s lipos and a Quark 125.

I may have to goto to 10xl or 9XL 5s or 6s lipos to get the amps down, to try and keep the 9920 cooler to race a 20 min race.