This letter deals with a Peak-to-Average Power Ratio (PAPR) reduction scheme for Orthogonal Frequency Division Multiplexing (OFDM) systems with Signal Space Diversity. An original algorithm for the selection of two Rotated and Cyclically Q-Delayed (RCQD) QAM constellations is proposed to jointly optimize the Bit Error Rate (BER) and the blind detection performance of a SeLected Mapping (SLM) technique. Simulation results show that the proposed method achieves a large PAPR reduction with no spectral spoilage, and also enhances the BER performance in the case of DVB-T2 over different channels.