The General Motors Research Laboratories have equipped two engine test cells with instrument systems containing minicomputers. These systems measure 200 variables and convert them to engineering units for display to the test operator on a high-speed video terminal. The computers also perform calculations such as mass airflow, composite inlet temperature, and equivalent horsepower, which are combinations of several measured variables. Many of the test parameters are corrected to standard conditions of temperature, pressure, and humidity. This paper discusses these systems, mentioning both past experiences and future plans for linking into a host-satellite network.