If it's a True 4S, I would say 40 is very possible with the right gearing. I ran 27mph towards end of my small 2250 3s and cheapo Feigao 8 2383kv motor, car weight 8bs
What is the quality of a Zippy ?
at that price I doubt the cells are of good quality, matched well, wont last as long as others.
Thunder power is the way to go
