What does it mean to "firewall" an aircraft engine?
"To firewall" is a phrase meaning to go to full power. Most aircraft throttle controls provide full power when moved to their furthest forward position - the direction towards the firewall separating the nose mounted engine from the cockpit in aircraft in the past. The phrase is still used, just as we "dial" a telephone even though the telephone dial is no longer used, either. A similar one for automobile driving is "pedal to the metal".