Butanol is an attractive fuel that can be utilized in compression ignition engines. This experimental study is to investigate the performance of direct injection diesel engine fueled with diesel-butanol blends with and without modification of engine operating parameters. This study includes three stages: Solubility of diesel butanol blends, property testing of the blends followed by an engine test with and without modification of nozzle opening pressure (190 bar, 200 bar, 210 bar and 220 bar), fuel injection timing (230, 260, 290 and 320 before top dead centre) and compression ratio (16:1, 17.5:1,19:1 and 20.5:1). Optimal parameters among these were attained by using an L16 orthogonal array and Taguchi method. Results indicated that 220 bar of nozzle opening pressure, 260 before the top dead centre of fuel injection timing and 19:1 compression ratio were found suitable for the blend containing 50% diesel and 50% butanol. This blend produced similar brake thermal efficiency, peak incylinder pressure, peak heat release rate, ignition delay, emissions of oxides of nitrogen and smoke. However, the emissions produced by this blend were found slightly higher compared to that of diesel. The novelty in this study is the utilization of 50% of butanol and this will be produced from biomass in the nearest future.