This SAE Recommended Practice establishes the test procedure, environment, and instrumentation to be used for measuring the exterior exhaust sound level for passenger cars, multipurpose vehicles, and light trucks under stationary conditions providing a continuous measure of exhaust system sound level over a range of engine speeds. This Recommended Practice applies only to road vehicles equipped with an internal combustion engine. The method is designed to meet the requirements of simplicity as far as they are consistent with reproducibility of results under the operating conditions of the vehicle. It is within the scope of this Recommended Practice to measure the stationary A-weighted sound pressure level during: - measurements at the manufacturing stage - measurements at official testing stations - measurements at roadside testing
Prior SAE Standards assumed vehicles could be operated at ¾ rated engine speed for the purpose of stationary sound pressure level testing. Technical development of vehicles and engines have changed the operation of many engines and vehicles under stationary conditions. This standard incorporates the changes in exhaust system configuration and the use of engine management and fuel cut-off systems during stationary conditions.