Do Z-moves used on a Pokemon under the effects of Protect or the move itself do more damage?

Question

For example, I used Flamethrower on Aegislash, or he uses King's Shield and I use Inferno Overdrive. Which will do more damage?

Answer 1

252 SpA Turtonator Fire Blast vs. 252 HP / 252+ SpD Aegislash-Shield: 152-182 (46.9 - 56.1%) -- 27% chance to 2HKO after Leftovers recovery

252 SpA Turtonator Inferno Overdrive (185 BP) vs. 252 HP / 252+ SpD protected Aegislash-Shield: 63-75 (19.4 - 23.1%) -- possible 6HKO after Leftovers recovery

The move itself.