quakebo

I have a rc18t which had a 4200kv motor in it and with my 1600nimh battery would last 30min gears were 14/60 or 14/55 but that motor went wrong so bought a 8200kv motor any ideas what the run time would be now. the gears are 14/57 and i am using the slipper clutch.

quakebo

If I add 3 more cells the same will it increase the run time or just make it faster.

SyCo_VeNoM

Probably more then likely make it not move as that would probably trash that motor.

cells is power delivered to the motor, capacity is the mah rating

Foxy

That is an extremely hot motor for that car. Your runtimes will be reduced by perhaps 30%, however your running time is not going to be dictated by your battery capacity any longer, it will be determined by motor heat.  I doubt you will get more than 10 minutes even on the street before you have to stop and let the motor cool down. Don't put any more cells that will make more heat. Don't put more than 7.4v through that or it will burn. Motors like that one are intended for 5 minute racing on prepared surfaces. If you plan to keep the motor niw that I have told you this, make sure you have a temperature tool to make sure the motor stays under 190*F. Again if you plan to use that motor, you are also overgeared. Try a 10 tooth pinion and keep an eye on temps. For general purpose use you should not go over 5000kv.