Engine RPM is a powerful application designed for measuring the RPM of an engine by analyzing its sound. Developed by Real-Time Specialties Inc., this app utilizes advanced signal processing algorithms to extract the frequency of the engine sound and accurately calculate the RPM.

Engine RPM is primarily intended for engine setup and diagnostics. It can be used with any internal combustion engine, from diesel tractors to aircraft engines to motorcycles and chainsaws. To get started, users need to set the number of cylinders and specify whether the engine is a 2-stroke or 4-stroke. Additionally, an expected RPM range should be set to guide the analysis algorithms accurately.

One of the key features of Engine RPM is the real-time graph of the autocorrelation graph, which aids in troubleshooting and adjusting the expected RPM range. However, it is important to note that the analysis requires a clear sound from the engine without excessive interference from extraneous noises. Therefore, it is not recommended to use the app in noisy environments.

While Engine RPM provides accurate RPM measurements, it is important to understand its limitations. The analysis cannot be performed on rapidly accelerating engines, and the app should not be considered a direct replacement for an operational tachometer. However, it offers a range of setup options, including update periods, cylinder count, 2-stroke or 4-stroke selection, low-pass filtering, and signal clipping.

Overall, Engine RPM is a reliable and versatile tool for engine setup and diagnostics. With its advanced signal processing capabilities, it offers precise RPM measurements for various internal combustion engines.