Frequently used internal combustion engines for driving highway vehicles are often tested to adjust performance outputs and exhaust emissions, with consideration for the production standardization and regulations of motor vehicles. In this work, a mini air station was designed and produced using the Arduino micro-controller to test the performance of an internal combustion engine. Instantaneous ambient temperature, pressure and relative humidity during engine operation are measured. At this time, the engine is subjected to steady state and transient regime tests and the performance data are reduced by a power correction factor to sea level conditions. The real-time weather data coming from the sensors over a 6 hour period every half-hour is continuously transmitted to the micro-controller. The microcontroller also continuously processes the measured data on an Excel page with the help of the environmental software of the microcontroller. According to the measurement results, the pressure and
temperature results can be accepted at the tolerable interval. However, the relative humidity in the mini-station is considerably lower than the reference stations, and the room air is quite dry as a result of the atmospheric temperature rising and the large heat transfer between the engine and the environment. In the tests of the heavy duty diesel test engine, where the power correction factors are calculated thanks to the developed mini air station, the effective motor power has increased by 1.9% to 4.7%. The effect of the correction factor on brake specific fuel consumption varies between 1.9 and 4.5% for 2100 rpm and 1200 rpm engine rpm respectively.