User blog comment:Staw-Hat Luffy/How strong is Z?/@comment-4800978-20121209204413

With the matter of Kizaru, it was a single explosion. All of one second of their fight. See it for how it is, not how you want it to be.

As for his "powers", Z has been shown to be a simple cyborg. Nothing more. Like Garp, a mass of physical power with a mechanical arm... which can cause large explosions upon contact. I'm guessing the Dyna Stone powers it, as in one trailer we see it being placed inside a large cylinder which matches a part of Z's arm.