Originally Posted by Vegatron75

The top speed of the 3800kv motor is is no way effected by the motor not being sensored. The sensor comes into play at a very low rpm, then actually shuts off as the rpms climb.

I'd say you were getting passed because your didn't have enough gear, to small of a pinion. With 13/62 the truck is geared for a little under 30mph. Hitting max RPM way to soon.

I run the 3800 and rx8, I run 15/62, plenty of grunt and plenty of top speed, w/ temps around 130-140. 15/62 is closer to 34mph.

All things equal the 3800 and 4000 should be very close to each other in performance.

Check out the chart for gearing and mph.... Note that battery voltage effects
MPH. The top chart is at 7.4v, the bottom chart is at 8.4V. Nominal voltage
for a 2s lipo and fully charged voltage for a 2s.


Could someone put the MPH/gearing chart on the front page? This chart could stop alot of needless "PINION" questions.