did battery mod
 

After putting the pcb and motor from my microsizer into my zip, i noticed its much faster, but run time not so good, so i ran two stock zip batteries in parallel, but it seems like run time is the same before i did mod. does anyone know how long i need to charge it, ive been doing 2 full charges on my microsizer charger, but it runs the same time. any suggestions?.my other question is what motor everyone suggests for speed, i ran the stock micro motor , then tried the zip nos motor, the micro motor much faster.

For pure top-end speed get the 3.8. But you either have to have a micro board or a multiple batt mod (or something else with higher voltage). This motor might not be the best bet for acceleration though.

If you have the NOS motor try it instead of the microsizer motor. My NOS motor runs at least twice as fast as the 2.6 in my microsizer.

Sorry I cant help you on the battery issue though.