Oh guys you're really helpfull, all thanks for that! i will try to modify my gearing like Squee said before, then tight the slipper a little bit less...
For ur information, my esc stays cold, no problem on that side... but my motor is at more than 100°C, because a little drip of sweat became steam when i put my face over the motor to see what was broken... not more than 120/130°C imo... what is impressive is the temperature of my motorplate and of my pinion!!! i never encountered this problem before (before i ran a HVmaxx, and this feigao9L with a 74/16 ratio....) 74/16 ratio was well and funny to run, until i tried to gear up with a 18T pinion... sorry i discover the limits of the Feigao 9L... :(

I will let you know what happens asap!

fab.