This study aims to improve biodiesel production by assessing the effects of biodiesel-diesel fuel blends on engine performance and emissions using response surface methodology (RSM). The biodiesel was produced by the transesterification process. Here we see how the molar ratio (A), catalyst quantity (B), reaction temperature (C), and reaction time (D) affect the biodiesel conversion rate. During optimization, a Box-Behnken design (BBD) based on RSM was employed. Ideal conditions for achieving a biodiesel yield of 98.2069% were a B of 0.811601 wt%, a C of 75.8837°C, a D of 98.2069 min, and A of 7:1. Adjusting parameters like engine speed and biodiesel fuel mix ratio enhanced engine behavior and condensed exhaust emissions. The trials were structured utilizing the central composite design (CCD) technique grounded on RSM. The optimum operating criteria for the engine were evaluated to be a biodiesel ratio of 12.5845% and speed of engine is 2011.24 rpm. Under these conditions, the power output was 50.0817kW, torque was 254.757 Nm, smoke opacity was 6.48966%, CO emissions were 270.009 ppm, and NOx emissions were 819.573 ppm. These findings indicate that appropriate adjustments in biodiesel-diesel blends and engine parameters can significantly enhance engine performance and reduce exhaust emissions, providing insights into more efficient and environmentally friendly fuel utilization. © 2025 Elsevier B.V., All rights reserved.