Wild Porsche 928 made modern cars quieter.

On average, modern cars are much quieter than cars of previous eras. The reason for this lies in the specially modified Porsche 928.

According to the automaker, this 928 was used as a noise test vehicle for over 30 years.

It is now retired and on display at the Porsche Museum in Stuttgart, Germany.

The car was built to help Porsche comply with noise regulations. To do so, engineers had to measure the noise generated by different parts of the car. Although Porsche was producing other models at the time, the 928 was deemed to be the perfect platform.

The 924, Porsche's entry-level sports car at the time, was excluded because the test “required a lot of power at low rpm,” Harald Mann, one of the testers, said in a statement. The 944 and 911 were excluded because of gearbox rattling under low loads and louder-than-normal engine noise, respectively.

The 928, which entered service in 1989, was used specifically to determine noise levels from tires. This meant that other noises, such as those from the engine and drivetrain, had to be kept to a minimum, which resulted in the 928 having an outlandish appearance.

Engineers moved the radiator to the front bumper and added a large barrel-like silencer for the intake to the front of the body. The hood bump houses a fan that draws hot air from the engine compartment. It is switched on only when necessary to minimize noise. An oversized muffler is mounted in the rear window to quiet the exhaust note. The driveshaft and gearbox were also insulated, and large rear fender flares were added to accommodate different tire sizes.

The stock five-speed manual gearbox was retained because, according to Porsche, it was already quite quiet. During the test, the 928 ran in front of Mike, averaging noise levels in second and third gear.

The test car also featured a prototype 5.4-liter V-8 that was part of the 928 GTS development program. This would be the ultimate version of the 928, which ceased production in 1995, some 20 years after its first public showing at the 1977 Geneva Motor Show; it would be the last V-8 Porsche road car until the Cayenne was launched in 2003.