Opposed-piston, two-stroke engines reveal degrees of freedom that make them excellent candidates for next generation, highly efficient internal combustion engines for hybrid electric vehicles and power systems. This dataset contains results from GT-SUITE simulations of an opposed-piston, two-stroke engine that explore the influence of key control and geometrical parameters, specifically crankshaft phasing and intake and exhaust port height-to-stroke ratios, in obtaining best thermal efficiency. The results are generally reported in the form of contours of brake specific fuel consumption (BSFC), as a function of the aforementioned geometrical parameters of interest. This dataset contains folders corresponding to each figure in the corresponding article. Each folder contains the MATLAB code and any data required to generate the figure.