Global trends in the development of spark ignition internal combustion engines lead to the adoption of solutions that reduce CO2 emissions and fuel consumption. Downsizing is a well-established path for this reduction, but it is necessary to use other technologies in order to achieve these ever more rigorous levels. A homogeneous torch ignition system is a viable alternative for reducing CO2 emissions with a combined reduction in specific fuel consumption and increased thermal efficiency. Thus a prototype adapted from an Otto engine with four cylinders is used for analysis. The performance and CO2 emission reference data were initially obtained with the baseline engine operating with a stoichiometric mixture. Then for the same conditions of BMEP, angular velocity and gradual lean of the mixture from the stoichiometry, the results of the adapted system are obtained. The results obtained demonstrate a reduction in the specific emissions of CO2, specific consumption and an increase of the thermal efficiency. The gains obtained are the result of a burning rate and consequently a lower ignition advance used, resulting in a greater turbulence and a knock lower probability. This feature allows the use leaner mixtures operation associated with the torch ignition system, making it an interesting artifice to increase thermal efficiency and reduce CO2 emissions.