I have the Tekin 1550 with 5s 4200mah Hyperion and I cut the throttle back to 90% for the mains and I am able to do a 15 min main. I cut the throttle back some because it forces me to be smooth and consistent. Too many guys think they are fast but they crash in every corner.

How much does your xt8 weigh? Mine was the exact same weight as my buddys losi 8t 2.0 on 4s.