HELP HERE ! Mamba maxx and feigao 9xl setup slow as hell!!!

[Dafni]

Well, a 9XL on 2S won't give you much rpm. This motor feels more at home on 5S.
I guess your intention was to use it on 4S :032:

Try it on 2 2S packs in series... twice the voltage will give you twice the rpm. But don't rev it up too much without load!

Another heads up: even two of those 4000mAh Batts won't do the trick in an EMaxx in the long run. Their discharge rate might be put to its limit, and the packs will suffer over time.

Hope this helps
DAF