One form of substituted energy is the production of HHO gas as a zero pollutant with the main raw source being water for use as fuel for internal combustion engines. There are several methods to produce HHO gas, one of which requires an HHO reactor which contains cells made of stainless steel as electrodes and water in the form of an electrolizer as a catalyst for producing HHO gas as a result of triggering a DC power source. This working principle underlies the modification of HHO gas production by experimenting with materials from an electric chassis containing stainless steel and treated with PWM 50 herz dutycycle 50 with a time span of 1 minute until a change in the polarity of the DC source occurs. The experimental results show that the reactor design with 13 plates, working at a voltage of 12 volts and a current of 10 amperes is connected to a stainless steel plate as an anode-cathode and the use of an electrolyzer (NaHCO3) can produce 0.151 liters of HHO gas. The results of HHO gas through polarity change treatment with an average time of 2.42 minutes and an efficiency of 10.148% while without polarity change treatment, an average time of 2.39 minutes and an efficiency of 10.219%.