Building a car that meets stringent noise level regulations is a challenging task for automakers, especially those specializing in performance vehicles. In the late 1980s, Porsche built a one-off prototype based on the 928 to test noise levels of different tire compounds. This unique vehicle was wrapped in cotton wool to isolate engine, intake, and exhaust noise sources. The radiator was positioned ahead of the front bumper, and hood scoops housed fans to cool down the engine. The large barrel on the hood was for the intake process, and the dual curved exhaust pipes extended to the highest point of the car. The bulging wheel arches allowed for different wheel and tire combinations.
**The Selection of the Porsche 928 for the Noise Test**
Porsche chose the 928 for the noise test car because an air-cooled 911 was too loud, and the 924 and 944 were not suitable for the task. The 928 provided power in the lower rpm range and had the necessary characteristics for the noise test evaluation.
**The Testing Process of the Porsche 928**
Initially, Porsche tested the car on existing facilities, but as the surface changed over time, they built an external noise measuring track with standardized asphalt for more accurate results. The 928 was equipped with slick tires and measured at a low 63 dB during the standardized flyby test at 31 mph, well below the legal limit of 74 dB at the time.
**The Results and Legacy of the Porsche 928 Noise Test Car**
While the Porsche 928 noise test car may not have been aesthetically pleasing, it served its purpose in helping Porsche meet noise level regulations and make its cars quieter overall. After more than three decades of service, the vehicle is now on display at the Porsche Museum in Stuttgart, showcasing its unique design and contribution to noise testing in the automotive industry.
Overall, the Porsche 928 noise test car exemplifies the innovative approaches automakers must take to meet regulatory requirements, even if it means creating unconventional vehicles for specific testing purposes. By prioritizing noise reduction in performance vehicles, companies like Porsche can continue to produce high-quality cars that adhere to stringent regulations while maintaining their brand’s reputation for excellence in engineering and design.