• This Porsche 928 was a noise test vehicle for over 30 years
• The wild-looking 928 is now on display in the Porsche Museum
• Porsche shoved a prototype 5.4-liter V-8 into this 928

Modern cars are, on average, much quieter than cars from previous decades. And you can thank a specially modified Porsche 928 for that.

As explained by the automaker, this 928 was used as a noise test vehicle for over 30 years.

It’s now retired and on display in the Porsche Museum in Stuttgart, Germany, where visitors can gawk at its unusual array of appendages.

The car was built to help Porsche comply with noise regulations. To do that, engineers needed to measure noise coming from different parts of the car. While Porsche had other models in production at the time, the 928 was determined to be the perfect platform.

The testing “required a lot of power in the lower engine speed range,” ruling out the 924 that was Porsche’s entry-level sports car at the time, Harald Mann, one of the testers, said in a statement. Noise also had to be carefully controlled, ruling out the 944 and 911 due to gearbox rattle at low loads and louder-than-normal engine sounds, respectively.

Entering service in 1989, the 928 was specifically used to determine the noise level from tires. That means other noises—like those from the engine and drivetrain—had to be minimized, hence the 928’s outlandish appearance.

Engineers moved the radiator to the front bumper and added a large barrel-like silencer on the front of the car for the intake. Bumps on the hood house fans that draw hot air out of the engine compartment. They’re switched on only when needed, minimizing noise. An extra-large muffler was mounted on the rear window to quiet the exhaust. The driveshaft and gearbox were also insulated, and large rear fender flares were added to accommodate different tire sizes.

The stock 5-speed manual gearbox was maintained because it was already fairly quiet, according to Porsche. In testing, the 928 would be driven past a set of microphones, with noise levels from the car in second and third gear averaged.

The test car also has a prototype 5.4-liter V-8 that was part of the development program for the 928 GTS. This would be the ultimate version of the 928, which ended production in 1995 nearly two decades after it was first shown at the 1977 Geneva auto show. It would be the last V-8 Porsche road car until the launch of the Cayenne in 2003.