Development of the J2835 On-Highway Motorcycle Sound Test Procedure
The 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.
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The SAE J2725 paper (2011-01-1614), “Development of the J2835 On-Highway Motorcycle Sound Test Procedure,” can be downloaded and purchased at http://papers.sae.org/2011-01-1614/
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The SAE J2825 standard, Measurement of Exhaust Sound Pressure Levels of Stationary On-Highway Motorcycles,” can be downloaded and purchased at http://www.sae.org/technical/standards/J2825_200905