The Edgetech DewTrak II-MO Hygrometer is specifically engineered to meet the precise humidity measurement requirements for Motor Octane Number (MON) and Research Octane Number (RON) testing. It uses the primary method chilled mirror dew/frost point condensation principle to determine water vapor concentration, combined with a pressure sensor to measure the barometric pressure of the motor intake air/fuel mixture.

The probe is designed for direct integration with engine test stands through a specially designed, robust metal manifold that fits onto the engine air intake duct. The manifold creates an air-tight seal while ensuring that only a minimal portion of the probe extends into the airflow, thus preserving all aspects of air delivery to the engine. Each manifold includes a removable, air-tight plug, allowing individual probes to be shuttled between multiple engine test stands for optimal measurement versatility. Probes can also be remotely mounted if required.

The instrument achieves exceptional accuracy of ±0.5 gr/lb for water content and ±0.044 inches of Hg for barometric pressure. It features selectable analog outputs (4-20 mA, 0-5 Vdc, or 0-10 Vdc), long-term stability and repeatability, and an IP65-rated enclosure. The DewTrak II-MO fully complies with ASTM Standards D2699, D2700, and D2885 for octane testing, making it the definitive choice for fuel research and engine development laboratories.