Boxing's Resounding Echo Continues
In the heart of every Subaru vehicle lies a unique engine, known as the horizontally-opposed or boxer engine. This design, a staple of Subaru's identity, is renowned for its distinctive "boxer sound" or "Subaru rumble." A symphony of asynchronous exhaust pulses, resonance, harmonics, and sound wave interference, the boxer sound is more than just an auditory experience—it's a cultural icon.
The secret to this iconic sound lies in the unequal-length exhaust manifold. Each cylinder in a horizontally-opposed engine emits exhaust gases at slightly different times and distances, resulting in an asynchronous pulse. This uneven timing creates unique resonance and harmonics, contributing to the characteristic uneven, growly sound.
The sound waves generated by this asynchronous pulse and varying resonance interfere with each other, creating the distinctive, rumbling pattern that has become synonymous with Subaru. This interference pattern is what sets the boxer engine apart from other engine designs.
For those who cherish the boxer sound, Subaru has made sure that the sound is preserved. The Sound Creator® system, initially turned down by the project team, was eventually accepted after a prototype was built and demonstrated. This system delivers intake sounds into the cabin, accentuating the sound during acceleration, ensuring the boxer sound remains a key part of the driving experience.
Subaru's commitment to the boxer engine is unwavering, even in the carbon neutral era. President Atsushi Osaki has vowed to continue developing horizontally-opposed engines, ensuring that the boxer sound will continue to resonate in future Subaru vehicles.
The boxer sound is deeply tied to the cultural identity of Subaru vehicles, particularly among enthusiasts who appreciate the unique auditory experience it provides. For fans who want to delve deeper into the world of the boxer sound, resources are available on Facebook and Twitter.
In contrast, equal-length manifolds, like the Tomei EXPREME Equal-Length Exhaust Manifold, are designed to optimize performance by ensuring all exhaust gases travel the same distance. This design can reduce the distinctive sound but may improve engine efficiency and performance.
Subaru's relationship with Toyota has grown stronger since their 2005 collaboration agreement, leading to a new business and capital alliance in 2019. The joint workshop in May 2024, attended by Subaru, Mazda, and Toyota, was a significant step towards new engine development in the electrification era.
The CB18 engine, developed by Subaru, was designed to improve response and exhaust gas performance while maintaining the boxer sound. A sports muffler by Subaru Tecnica International (STI) was key to maintaining the boxer sound in mass production for the CB18 engine.
From the design of the first-generation BRZ to the return of the boxer sound in the 2020 second-generation Levorg, the boxer sound has been a constant element in Subaru's vehicle lineup. The boxer sound is considered to be safely in the hands of truly appreciative Subaru fans, who continue to cherish this unique and iconic part of the Subaru driving experience.
*Note: The STI sports muffler is a registered trademark of Subaru Tecnica International (STI).
[1] Tomei EXPREME Equal-Length Exhaust Manifold: https://www.tomei.com/products/exhaust/exhaust-manifold/expreme-equal-length-exhaust-manifold/ [2] Subaru Levorg: A Return to the Boxer Sound: https://www.subaru-global.com/en/news/2020/0908_01/ [3] Subaru BRZ: The Sound Creator® System: https://www.subaru-global.com/en/news/2012/1029_01/ [4] The Science Behind the Subaru Boxer Sound: https://www.subaru-global.com/en/technology/boxer/sound/
The boxer engine's unique sound, a cultural icon, is a result of the uneven exhaust pulse created by the horizontally-opposed design. In contrast, equal-length exhaust manifolds, like the Tomei EXPREME Equal-Length Exhaust Manifold, are designed to optimize performance but may reduce the distinctive boxer sound.
Subaru's commitment to the boxer sound in the carbon neutral era is evident in the development of the CB18 engine, designed to improve performance while maintaining the iconic sound, aided by a sports muffler from Subaru Tecnica International (STI).
