What do you have battery current limited to in the Zilla? You say 276V pack voltage and 500kW power. So if battery current was equal the max 2kA current of the Zilla, that would be about 250V pack voltage for 500kW out of the pack, shaft power would be lower due to losses of course. Have you ever run at 2kA and 250V? How do you expect to get that performance from a "small" lithium pack without grossly exceeding the max discharge rate of the cells? Seems hard to get a pack that will do that. What is your 0 to 60 mph time? Should be a rocket if you can get that full 500kW!