Rotational gain has been studied largely under active self-motion, where users control their own movement. In multiple VR scenarios, the user is under passive self-motion: their body is moved by a training simulator, a motorised chair, or a vehicle-based VR application. Users may be less sensitive to manipulation under passive motion - especially when engaged in a secondary task - meaning motion experiences could be expanded by high gains and even opposed virtual-physical motion. We identified both the perceptible and maximum comfortable thresholds of rotational gain when passively turned in a motorised chair, with and without a task, for the first time. We then applied those thresholds to an ’unbounded’ in-car VR game where the user experiences an entirely different route to their physical movement. We provide the first guidelines for creating enhanced passive motion experiences and open the design space to new applications not restricted by physical motion.