Yes. It's a really handy tool to have at the dyno. Many times we have been told incorrect compression ratios for engines that would have resulted in using the wrong octane fuel. More often than not the customer doesn't know what the compression ratio is. It's a fairly quick way to find the compression ratio without tearing the motor apart or guessing. The down side is they are expensive. We charge $25.00 to whistle on the dyno. More if the motor is in the vehicle on the chassis dyno depending how long it takes. I don't think it's paid for itself yet but it's saved my *** a few times and I would be lost with out it.
