Motor Trend wrote an article about the Integra's exhaust and why they went with its curly design. According to Honda they're "coiled-type silencers". Rather than using a normal muffler, Honda is lengthening the exhaust pathway, lowering the resonance frequency.

How The Acura Integra's Exhaust Looks
The Integra's post-cat piping (aft of the catalytic converters) is a bit different. As we mentioned previously, this setup is nearly identical on the Honda Civic Si, which shares a platform, engine, transmission, and general layout with the new Integra. While the piping follows a relatively traditional central pathway rearward, toward the back of the Integra, via a small tunnel, upon reaching the rear axle area, it splits into a T-shape, with one pipe turning to the right and another to the left.

These two pipes bend slightly rearward and lead to small resonators, one per side, before taking a 120-ish-degree bend toward the vehicle centerline, followed by another (by which point the pipes are now flowing toward the front of the car), followed by another bend that points the piping back to the side of the car, and finally a gentler 60-ish-degree bend that spits the exhaust straight back, out from beneath the Integra's rear bumper. Why?

According to Honda, those squiggles in each exhaust outlet are, in fact, silencers. They serve essentially the same function as a muffler—Honda calls them "coiled-type silencers"—and their curious shape is highly intentional. While, like everything on a modern vehicle, their shape is somewhat influenced by the allowable space within the bumper and underbody area behind the rear axle, the specific pathway that piping takes plays a crucial role in the surprisingly guttural low-rpm sound the Integra and Civic Si make.

By snaking the exhaust piping into that circular route, Honda is lengthening the exhaust pathway, lowering the resonance frequency without using a traditional muffler . Honda engineers tell us that the design as first installed in the Si also emphasizes the 300Hz to 600Hz frequencies "to deliver a more aggressive sound." Skipping the muffler, Honda also was able to achieve that sound with a 27-percent increase in exhaust flow.

Automotive tire Motor vehicle Door Automotive design Automotive lighting

Product Bicycle part Auto part Automotive exterior Font