Yep, "balls out" and "balls to the wall" are respectively the steam train and fighter plane expressions for "full speed" (similar to "full throttle" or "pedal t

Yep, "balls out" and "balls to the wall" are respectively the steam train and fighter plane expressions for "full speed" (similar to "full throttle" or "pedal to the metal"). Neither expression has anything to do with testicles. In any event censoring the word "balls" (even when used euphemistically) is a bit weird.