Globally, energy demand has risen in recent years, owing partly to the world's massive population boom. Fossil fuels, the most often used fuel today, are responsible for a number of environmental issues. This results in the need to reduce reliance on all fossil fuels which is the solution for new renewable energy sources such as biofuels. These biofuels are considered as potential sources for meeting required energy demand that is a threat in the future. The production of biodiesel has been constantly increasing as they are mostly obtained through harvesting repeatedly. Diesel engines may eventually be replaced with biodiesel, a renewable fuel. The best alternate for diesel engines is considered as biodiesel because of its biodegradability, oxygenation, sulfur-free nature, and lubricity. It is a more desirable power source because it is less harmful to the environment and produces less pollution. Decrease in CO<inf>2</inf> pollution and increase in output quality makes the biofuels to keep continuously evolving and research work done constantly, and this investigation aims at finding out the potential of using bio-oil from soapnut oil. This paper mainly aims to quantify fuel flow and the exhaust analysis of B20 soapnut oil methyl ester as well as the product's performance and emission characteristics. © 2025 Elsevier B.V., All rights reserved.