A few of us are beating on the first production models to make sure that when they do release them, there arent any surprise failures.
I ran the VF4.0 (4000kv) 4 pole in my Tekno this past weekend on a fairly small, tight indoor track, average lap times mid 14's, with a 15t it temped at 135. That was with a fan and heatsink, ambient temps were mid to low 90's.
I've had the fan and heatsink on my RevTech 3800kv and it temped at 165-170 on the same track, same esc setups everything.
Power was very linear and strong with the 4k, not overwhelming.
Later on I went to a 16t and ran a full pack after the races (about 10-11 mins) and it temped at 165-170. No fade whatsoever, still had the same pop for the double/table and still blistered down the straight just like it did the first lap.