What capacity in kva diesel generator is required to run a 3 phase 20hp compressor?

A 20 hp piston motor compressor at 208/230v appx. 50 amp running, and 100 amp locked rotor current, requiring 70 amp heaters. A rotary screw will demand apprx. 20% greater locked rotor, but about the same running, and perhaps 80 amp heaters. Halve most all for 460/480v.

A 12 - 15kva generator should suffice. If the budget will sustain, go for a 25kva.