[Ryephile]

Ok, same starters. Sounds like you need to do a cranking comparison with a ZL1. I'd also contact a tuner to have them see if there are different ZL1 cranking parameters. I haven't checked so that's just a theory, but it's likely there are differences.

Just for sanity, make sure your bypass valve is operating correctly. If it's closed during cranking, it'll add more parasitic drag.