What is the function of the muffler?

If the exhaust gas produced by combustion in the engine were allowed to discharge outside the car directly, it would make a very loud noise that humans could not bear. The muffler is a part that has a section called a "silencer" that reduces the sound and emits exhaust gas outside the vehicle.

The muffler that is used as an OEM product has various ingenuity in a large silencer to reduce the sound. However, there is an aspect that it is difficult for the exhaust to flow smoothly inside the muffler due to various resistances. Also, a large silencer is disadvantageous in terms of weight.


What are the characteristics of sports mufflers?

We will explain the sports muffler "Hi-Power Spec LII" for GR86/BRZ as an example. In the OEM mufflers, it enters into one large silencer from the "middle pipe", and the sound is eliminated and exhausted inside. On the other hand, the HKS muffler is divided into two paths after passing through the middle pipe, and each exhaust through a small silencer. In order to efficiently flow the exhaust, Various measures have been taken to increase efficiency, for example, increasing the diameter of the middle pipe itself and making the silencer a structure that allows the exhaust to flow in a straight line.

Silent Chamber

The volume increases as the exhaust gas flows efficiently, and you can enjoy a sporty sound.
However, if you change the layout or pipe diameter in pursuit of efficiency, a muffled "boom" sound may occur. HKS's muffler provides the "Silent Chamber" that suppresses the muffled sound while providing the comfortable sound that matches each vehicle's characteristic suitably.

In terms of performance, power increases at high RPM, where there is a lot of exhaust flow because the exhaust flow becomes smoother. Depending on the muffler, the weight is also lighter, so the driving performance will also be improved!

Does HKS's muffler pass the Japanese car inspection?

For those who are thinking about replacing their muffler, the sound volume is definitely something to be concerned about. To use the HKS mufflers safely for customers, all volume levels meet the ``JASMA standards'', which are stricter than the national ``safety standards''.

Advantex® glass wool (CONTINUOUS FIBER)

Furthermore, in order to maintain the sound deadening performance for a long time, we are particular about the sound deadening material "glass wool" in the silencer, and we have designed it to be used for a long time by using a durable material called "Advantex® glass wool."

Features of the HKS muffler series

HKS has a lineup of various muffler series, and the main feature is that we have mufflers that suit the various needs of different cars. For example, in addition to the "Hi-Power Spec LII" introduced earlier, GR86 has a lineup of three mufflers: "LEGAMAX Sports" and "LEGAMAX Premium."


"Hi-Power Spec LII'' is a series for using thin stainless steel material, and as the name "Spec L II (Light = Light)'' suggests, it is as light as a titanium muffler at an affordable price. The straight structure also emphasizes exhaust efficiency, and it is a muffler that achieves performance improvement in both power and lightness!

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リーガマックス スポーツ

"LEGAMAX Sports" is a series that achieves the contradictory elements of "low exhaust pressure" and "quietness." We have created a muffler that allows you to enjoy everything from starting the engine in a residential area to sports sounds at high rpm!

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"LEGAMAX Premium" is a muffler series that allows you to enjoy a stylish rear appearance and sound. A highly effective muffler that easily enhances your car!

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