Growing concerns over air pollution and global warming have intensified the need for more efficient internal combustion engines with lower fuel consumption and emissions. At the same time, engine downsizing and the adoption of advanced technologies have significantly increased the complexity of modern engine systems. Under these conditions, insufficient calibration of engine control parameters can lead to substantial time and cost penalties during engine development. Therefore, calibration methodologies must evolve in parallel with engine technologies. In modern engine management systems, the increasing number of actuators has significantly expanded the calibration effort required for ECU mapping. One effective way to reduce this effort is to determine feasible operating ranges for the actuators before conducting engine-level calibration experiments. This enables the definition of practical constraints for key calibration variables, such as air-fuel ratio, spark timing, valve timing, injection timing, injection split ratio, and fuel pressure, thereby reducing the number of required test points. This study was conducted at Iran Khodro Powertrain Company (IPCO) and focused on turbocharged gasoline direct injection (GDI) engines equipped with variable valve timing (VVT). A benchmarking-based approach was used to extract suitable actuator operating ranges from several comparable engines. The engine operating map was subsequently divided into three regions in order to constrain the experimental domain and limit the number of candidate calibration states. This approach eliminated the need for exhaustive point-by-point mapping and reduced the actuator search space for calibration experiments by up to 99%.