My 8 project

[SpEEdyBL]

4s and 100% endpoint is certainly more efficient than 5s and 75% endpoint. If you use a pinion gear 4/5 the size with 5s and 100% endpoint you'll probably get even more runtime.

[lincpimp]

What brand/type clutch and bell do you use? Is it the traxxas style or a std 1/8 scale clutch? You should be able to go down to a 12t bell, and go back up with the throttle epa...

Also remembered that losi brought out a 50t spur, that would help lower the gearing too...