Quote:
Originally Posted by Shiny
Does a whistler measure static CR? I'm ignorant but curious how valve timing doesn't affect this?
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The Katech Whistler is an electronic device that accurately measures an engine’s compression ratio without disassembling the engine.
The Whistler Compression Ratio Tester is designed to determine the static compression ratio of virtually any engine quickly and accurately. It is widely used by race sanctioning bodies like NASCAR and SCCA to enforce compression ratio rules, as well as by engine builders to verify actual compression ratios without relying on volume calculations.
The device operates using acoustic principles. Air is injected into the cylinder through a spark plug hole, and the Whistler measures the resulting tone as the piston moves to top dead center (TDC). This tone correlates with the combustion chamber volume, which, combined with the number of cylinders, engine displacement, and temperature, allows the Whistler to calculate the compression ratio to the nearest hundredth of a point. Accuracy is reported at ±0.05 actual static compression.
The pictures below are of the RAIII in the '70 Formula; original engine before rebuild being tested on the Whistler.
Dennis