The case study presented here showed experimental data on fuel consumption and, gas emission when a HHO unit is implemented on an IC engine operated under hot weather conditions. For this work a 1496 cc IC engine manufactured by Toyota, model 1NZ-FE VVT-I, was utilized. Data generated during 4 months at the Paraguayan hot summer is complied. Average temperature during data collection was 35C ambient. HHO unit temperature was monitored and kept at 5 amps for normal operating condition. A 95 octane fuel from a single supplier was utilized at all time. The results confirmed a fuel consumption reduction of 12% in city. These results are consistent with other works such as J. Wall [1] and S. Musmar [2]. On the other hand, emission tests have been conducted with varying the engine speed. Results showed that carbon monoxide (CO) and hydrocarbon (HC) have been reduced from 0.4 to 0.05 and from 364 to 171 respectively when a mixture of HHO, air, and fuel was used. In addition, the carbon dioxide concentration has been increased to about 7% indicating a more efficient combustion.