Rizqi Fitri Naryanto, Ibnu Basir Nurudin, Adhetya Kurniawan, Ahmad Mujaki, Ranu Iskandar
Various innovations have been developed to make the use of motorized vehicles better in terms of performance. One innovation that is claimed to improve engine performance is the use of a diffuser on the exhaust. The aim of this research is to determine the effect of the number of diffuser holes in the exhaust on the performance of the 4-stroke, 1-cylinder Supra X 125 FI petrol engine. The method used is a quantitative approach with research design true experimental design. The research results obtained show that the use of a diffuser results in a decrease in torque and power but on the other hand saves fuel consumption. The lowest torque reduction occurred when the engine used a diffuser with one hole with a decrease of only 1.9%. The highest power reduction occurred in engines that used a diffuser with three holes with a decrease of 4.2%. In terms of fuel consumption, using a diffuser on the exhaust can reduce fuel consumption. The highest reduction in fuel consumption at 1000 rpm engine speed was 9.3%, 4000 rpm engine speed was 16.3%, and at 7000 engine revolutions it is 14,9 %. © 2025 Author(s).
Department of Mechanical Engineering, Faculty of Mechanical Engineering, Universitas Negeri Semarang, Semarang, 50229, Indonesia; Department of Automotive Engineering Education, Faculty of Mechanical Engineering, Universitas Negeri Semarang, Semarang, 50229, Indonesia
