Bahan bakar merupakan kebutuhan utama pada mesin agar mesin bisa bekerja. Tingkat konsumsi bahan bakar pada suatu kendaraan pada era ini sangat diperhatikan karena harga bahan bakar sendiri cenderung naik. Dengan konsumsi bahan bakar yang hemat diharapkan mesin tetap memiliki peforma yang tinggi dan emisi gas buang yang rendah. Penelitian ini bertujuan untuk mengetahui dan mendeskripsikan kemampuan muffler tipe resonant, three pass tube dan off-set tube terhadap reduksi konsumsi bahan bakar pada mesin Toyota Kijang tipe 5K. Jenis penelitian adalah penelitian eksperimen (experimental research). Variabel independen adalah knalpot standar mesin Toyota Kijang 5K dan knalpot modifikasi yang didesain ulang bentuk muffler-nya menggunakan muffler tipe resonant, three pass tube dan off-set tube. Variabel dependen adalah konsumsi bahan bakar, tekanan balik (back pressure), dan temperatur gas buang. Variabel kontrol adalah putaran mesin yaitu 1000 rpm, 1500 rpm, 2000 rpm, 2500 rpm, 3000 rpm, 3500 rpm, 4000 rpm, 4500 rpm, dan 5000 rpm, temperatur oli mesin ? 60 ºC, temperatur ruang uji 20-30ºC, kelembapan udara ruang uji 60-70%RH, bahan bakar yang digunakan pertalite, dan kecepatan angin < 9 m/s. Bahan penelitian yang digunakan adalah plat galvanis dan bahan bakar pertalite. Objek penelitian adalah mesin Toyota Kijang tipe 5K. Standar pengujian konsumsi bahan bakar berdasarkan standar SNI 7554:2010. Teknik analisis data menggunakan metode deskriptif kuantitatif. Hasil pengujian menunjukkan bahwa penggunaan muffler tipe resonant, three pass tube dan off-set tube dapat mereduksi konsumsi bahan bakar sebesar 8,29 %, 15,06 % dan 13.71 %. Muffler eksperimen yang terbaik untuk mereduksi konsumsi bahan bakar didapat pada muffler tipe three pass tube, karena memiliki tekanan balik (back pressure) yang lebih besar sehingga konsumsi bahan bakar yang dibutuhkan mesin menjadi lebih rendah karena pada saat overlapping katup, udara dan bahan bakar yang baru masuk ke ruang bakar tertahan oleh gas buang. Kata Kunci: Muffler, resonant, three pass tube, off-set tube, konsumsi bahan bakar. Abstract Fuel is the main requirement for the engine so the engine can work. The level of fuel consumption in a vehicle in this era is highly considered because the price of fuel itself tends to rise. With low fuel consumption, it is expected that the engine will continue to have high performance and low exhaust emissions. This study aims to determine and describe the ability of resonant type mufflers, three pass tubes and off-set tubes to reduce fuel consumption on Toyota Kijang type 5K engines. This type of research is experimental research. The independent variable is the standard Toyota Kijang 5K engine exhaust and modified muffler that was redesigned using a muffler type resonant type muffler, three pass tube and off-set tube. The dependent variable is fuel consumption, back pressure, and exhaust gas temperature. The control variables are engine speed which are 1000 rpm, 1500 rpm, 2000 rpm, 2500 rpm, 3000 rpm, 3500 rpm, 4000 rpm, 4500 rpm, and 5000 rpm, engine oil temperature ? 60 ºC, test chamber temperature 20-30ºC, humidity test chamber 60-70% RH, the fuel used is pertalite, and wind speed <9 m / s. The research material used was galvanized plate and pertalite fuel. The object of research is the Toyota Kijang type 5K engine. Fuel consumption testing standards are based on SNI 7554: 2010 standards. Data analysis techniques using quantitative descriptive methods. The test results show that the use of resonant type mufflers, three pass tubes and off-set tubes can reduce fuel consumption by 8,29%, 15,06% and 13.71%. The best experimental muffler to reduce fuel consumption is obtained on the muffler type three pass tube, because it has a back pressure that is greater so that the fuel consumption needed by the engine is lower because at the time of overlapping air valves, and new fuel into the combustion chamber held by exhaust gas. Keywords: Muffler, resonant, three pass tube, off-set tube, fuel consumption.