The zhanchi is just a very poppy cube. Mine was great for about two months but then it just started popping more and more. Your better off getting the newer cubes like the Gans356, Hualong, or Yuxin or something of the sort. The newer cubes don't seem to pop as much (I never popped my hualong in the 2 months I've had it so far).
My zhanchi has a similar problem. I found that one of the screws is unwinding itself. when i disassembled i found that the screw unwinds when i pull the center piece and turn it. whenever i get a little fast the cube lock ups and explodes since the tensions become loose. does anyone else have this screw-unwinding-itself problem ?