The use of torch ignition systems in spark-ignition engines represents an interesting option in the efforts to reduce pollutants emission and specific fuel consumption. Based on this idea, this paper presents a 3D model of a prechamber created for a spark-ignition engine and focuses on the numerical analysis of the fluid flow inside the modified chamber. This kind of analysis is very important once it allowed evaluating aspects like turbulence parameters, pressure inside the chamber and prechamber, fluid recirculation and a possible prechamber’s geometry for the engine. The studies were done in a four valve Single Cylinder Research Engine - SCRE. For the numerical modeling and fluid flow investigation it was used STAR-CD Software. The numerical results permitted to characterize the fluid flow in the modified engine and compare it with the standard engine, which showed significant differences and an interesting potential.