Want to start a brushless speed demon.

[snellemin]

Personally for speed runs, I like to keep my motor at around 50-60Krpm under load. So a lower kv and/or longer motor with more voltage(higher efficiency) would be able to handle a bigger load(gearing) to reach your top speeds. I suggest you get a datalogger to help reach your goal and not blow up stuff in the process.

Goofing off I keep motor rmps at around 30k or so.