The present paper elaborates on the experimentation on a single-cylinder turbocharged direct injection engine using two different high free fatty acids nonedible oils and diesel blend as injected fuels. The experiments were performed to determine the post-mixed biodiesel fuel characteristics and to evaluate the overall performance and emission characteristics, at different loading conditions keeping injection timing (23°bTDC), injection pressure (220 bar), and speed (1500 rpm) constant. The result depicted a higher brake thermal efficiency (2.18%↓), exhaust gas temperature (2.5%↑) with an increase in loading condition. Consider the emission analysis, smoke opacity (11.64%↓), nitric oxide (0.9%↓) show a reducing trend on the expense of higher carbon monoxide (15%↓), and hydrocarbon (51.8%↓) for w10j10 post-mixed blend test fuel at all loading conditions, in contrast to conventional fuel. Based on the abovementioned discussions, it might be concluded that post-mixed biodiesel blends can evolve as a potential substitute for conventional fuel without much engine modification thereby, ensuring sustainability and security to the environment. © 2022 by Begell House, Inc. www.begellhouse.com.