Diesel engines applications cover a broad spectrum, ranging from vehicles that transport passengers and move goods to specialized vehicles and equipment used in the construction and agriculture industries. However, diesel engines are a significant source of pollutant emissions that contribute to poor air quality, negative human health impacts, and climate change. This experimental case study develops emission maps based on statistical models for a single-cylinder, four-stroke, air-cooled diesel engine as a function of torque and engine speed. The tested fuels were 100% diesel (B0), and blends with 5% (B5) and 10% (B10) biodiesel originating from African oil palm (Elaeis guineensis). The study explores the individual contributions of NO and NO2 to NOx and discusses the correlation between CO and O2 emission maps. The statistical models of CO, CO2, and O2 feature R2 adjusted values greater than 0.8, while the models of NO and NO2 show R2 adjusted values of around 0.6. The apparent discrepancies in CO emission trends among previous studies are explained. The emission maps developed here are a practical alternative to predictive models and can assist in engine calibration and aftertreatment optimization while saving time and costs.