Modern distributed systems deployed over wireless ad-hoc networks are inherently dynamic and the issue of designing dependable services which can cope with the high dynamics of these systems is a challenge. Byzantine failure detectors provide an elegant abstraction for solving security problems; however, very few work has been proposed for the new context of dynamic networks. This paper advocates the adoption of the time-free approach to detect Byzantine failures in such systems. This approach does not rely on timers to detect progress failures; it is suitable to deal with the unpredictability of the node's behavior and communication medium on these networks, favoring scalability and adaptability.