The influence of a PbO excess in the PZT composition Pb0.92 + xSr0.08 (Zr0.515Ti0.455Nb0.02Mn0.01)O3 + x (0 < x < 0.12) was investigated. A sintering method was chosen for the ceramics manufacture. Weight-loss experiments were performed to compare the final PbO content values to the theoretical x, and a nearly stoichiometric area was observed for 0.01 < x < 0.08, corresponding to optimal piezoelectric coefficients. Substitution of Mn ion in a +2 or +4 valency state was studied. Measurements of vibration velocities with a view to ultrasonic motors application were carried out.