A quantitative analysis of the temperature and pressure profiles of the 77Se and 13C nuclear spin-lattice relaxation time T 1 is used to determine the amplitude of the short range electron-electron coupling constant in the organic conductors (TMTSF) 2PF 6, (TMTTF) 2PF 6 and (TMTTF) 2Br. The starting part of the analysis is the observed 1D relation T 1 −1 = C OTχ S 2 + C 1 between the relaxation rate and the uniform susceptibility s in the presence of spin fluctuations from which one one can extract the temperature dependence of the magnetic spin susceptibility under pressure. The data are corrected in order to fit it with the constant volume theoretical expression for S and an intermediate value of the backward scattering diffusion constant (g 1) is found for both families.