Speed Calculations?

I think the 9xl has 1800kv? So bitire will give you speed but You lose torque? I watched the Losi 8ight that had a 9xl on 4s and it was crazy! It was just spinning the whole time! When Every I go with the brushless I going to be making some more videos. So new comers can watch the crazy power of brushless!

Will FLM diffs, Integy diff case, Integy diff collor, and traxxas bulks be enough to handle the power?