1512 2.5D vs 3D on 5S?

[SpEEdyBL]

Originally Posted by DRIFT_BUGGY

I have currently got a 1512 2.5D (2050KV) in my 8IGHT and running it on 5S 5000mah geared at 41mph and it gets pretty hot 180F+ The 2.5D on 5S makes 37925rpm and most people recommend motor rpm's to be between 30K - 35K. I once had the buggy geared at 44mph and it was great (apart from the temp of course) had plenty of speed. Was thinking of giving the 3D a go and see if temps would go down. 3D on 5S makes 31450rpm which is 6400rpm difference. Is the 3D going to be able to run at 44mph or becuase it is a slower motor than the 2.5D it won't be able to run that fast without overheating?

30 -35K is only for feigao motors. Neu motors can go much higher before efficiency starts to drop off.

The 3D has more resistance than the 2.5D, which means it will heat up more at a given amp rate because copper loss = resistance x amps^2 and the 3D has about 1.4 times the resistance as the 2.5D. The only time a higher wind motor will run cooler is if iron losses (energy lost in the magnet) are signficant, but this only happens at high rpms.

And btw, Y winds are slightly more efficient than D winds, so you may be better off going with the 1.5Y rather than the 3D. But before doing anything, try different pinion gears and record the temps each time. A GOOD motor should run the coolest with the smallest pinion gear, and gradually get hotter as the pinion gear goes up. If your motor still gets hot with a small pinion gear, there is something wrong with your motor or setup.