cooling pipe, just to see...

this part has been made with FDM (fused depositition modeling) process...
The material is ABS and this pipe is my first prototype... i have to work to enhance the air flow... perhaps extracting the heat will be more efficient than blowing on the motor...

To solve my problem i think to go 4S lipo, loosing a bit of speed, with my C9L, but i really have problems with ratios... what will be a good ratio? i thought about 66/18... (with lightning diffs) Using 4S make me come back under the rpm limit of this motor, i reach 39krpm on 14.4V... (i can reach 35.8mph theorically with 66/18)
Using 6S lipo is too heavy, i prefer to stay light...