We studied the external aerodynamics of a car employing CFD numerical simulations with the cumulant LBM on GPUs. We performed the analysis for different grid resolutions and for single- and multi-GPU simulations. In order to evaluate the performance of our implementation, we also carried out numerical simulations with the FVM on a CPU cluster using OpenFOAM^®. The results showed a good agreement to experimental data and the cumulant LBM computation was substantially faster than the FVM. The cumulant LBM multi-GPU implementation demonstrated also high parallel efficiency. Our work shows that the cumulant LBM on GPU is a valid alternative to FVM on CPUs to perform accurate and efficient CFD simulations of complex engineering problems.