Katech WHISTLER Compression Ratio Tester

Tool to test the compression ratio of any engine

The Katech WHISTLER™ Compression Ratio Tester is an electronic device that instantly determines the compression ratio of virtually any engine. Using the WHISTLER is easy; remove a spark plug and screw the WHISTLER adapter in its place. Enter the number of cylinders, CID, and temperature of the engine into the WHISTLER. Then, bring the engine to TDC, and the unit will display the compression ratio to the nearest hundredth of a point. All you need is a low volume air source and a 120V AC supply. The Whistler is now accurate to ± .05 compression!

• No limitation on the number of cylinders  


• No restriction on engine displacement


• Calibrated to chamber volumes of 40cc to 120cc


• Engine temperature range 30 to 200° F


• Onboard barometric pressure sensor


• Recommended minimum air tank volume of 10 gallons

The new redesigned unit is included with the Katech WHISTLER™ Compression Ratio Tester

• FN, BN, BL, J and 18mm spark plug adapters (12mm motorcycle available)


• Built in verification bottle (allows you to check the accuracy of the unit at any time)


• Easy to understand instruction sheet


• Pelican Hard Case

PART NUMBER | KAT-A0250-G

Need calibration or repair? Please use the following form: Whistler Calibration and Repair Request Form (see instructions tab above)