Abstract: The current study involves the renewed biodiesel derived from non-edible as Juliflora and Candlenut oil into biodiesel using a two-stage trans esterification process. The physiochemical characteristics of biodiesels are analyzed and experiments are carried out employing a single-cylinder four-stroke diesel engine to test several biodiesel blends as B0, B20, B30 and B40 for, performance, and emission characteristics and experimental outcomes were analysed using Central composite modelling optimization. The results indicates the brake specific fuel consumption (0.285 kg/kW h) lower and the Brake thermal efficiency 31.8% higher for the 20% blended diesel. These values are comparable to diesel, with variations of 3.7 and 3.2% respectively. During the experiment, the emission parameters of HC, CO, and smoke were 17.67, 8.2, and 9.45% respectively, lower for CJ20 blend than diesel. Nevertheless, NO<inf>x</inf> emission is 4.2% higher than base fuel, while minimal difference and among the lower than other blends. Furthermore, the Central composite design was developed and find the optimal results of a CI engine achieved. Overall results confirm that 20% CJ biodiesel blended diesel is the alternate of the standard diesel. © 2025 Elsevier B.V., All rights reserved.