Development of the J2835 On-Highway Motorcycle Sound Test Procedure

motorcycle-industry-council-logo1The MIC, MIC consultant Tom Austin (Sierra Research), MIC member Chris Real (DPS Technical, Inc.), and SAE Motorcycle Technical Steering Committee Chairman John Lenkeit (Dynamic Research Inc.) co-authored a paper on the development of the SAE J2825 on-highway stationary sound test procedure. The SAE published the paper, which was presented at the 2011 SAE Noise and Vibration Conference in Grand Rapids, Michigan on May 17th. The 14-page paper details the field testing, data analysis, evaluation of test site conditions, validation testing and even field testing.

In response to a growing need for a practical and technically valid method for measuring exhaust sound pressure levels (SPL) of on-highway motorcycles, the SAE Motorcycle Technical Steering Committee has developed Surface Vehicle Recommended Practice J28251, “Measurement of Exhaust Sound Pressure Levels of Stationary On-Highway Motorcycles,” which includes a new stationary sound test procedure and recommendations for limit values. Key goals of the development process included: minimal equipment requirements, ease of implementation by non-technical personnel, and consistency with the federal EPA requirements; in particular, vehicles compliant with the EPA requirements should not fail when assessed using J2825. Development of the recommended practice involved a comprehensive field study of 25 motorcycles and 76 different exhaust systems, ranging from relatively quiet OEM systems to unbaffled, aftermarket exhaust systems. For the various motorcycle/exhaust system configurations, SPL measurements were made using the EPA pass-by procedure and several different stationary measurement methods.