Originally Posted by TJMac

Currently running the same setup as you. 20/81 and the X12 gets pretty hot...however....I've been told X12s run hot so no worries. I started at 18/81 and top end was only ok. Worked up to 21 and didn't seem to be gaining anything other than extra heat so I backed it off one and it runs stupid fast and the heat is right at the limit. With the 8.5 you won't need to run the fan on the R10 but that big block of aluminum will get warm. I run the fan on mine all the time 'just because' and even after a full practice pack the esc comes off the track cool.