9920 let out smoke...seems fine?

[lydiasdad]

I recently grabbed one of the bk 9920's Mike had on sale. I installed it in my rustler with 6s a123 and a 9xl using a receiver pack. When I took it for it's first test run everything was working great, then smoke out of the side where the motor wires come out. I unplugged it immediately to double checked everything. It all looked fine. I plugged it back in and it seems to be working fine. I did some searching and found others had similar problems with smoke leaking out of their bk's. It is not stuttering or acting funny at all. Some people reported that their power was reduced even though the controller still worked. My question is, how do I know if it is reaching full speed? With 6s and a 9xl it could only be at 80% and it would still be crazy fast. Thanks.