Here's some good info on the ins and outs of exhaust systems... Hopefully this will help everyone comprehend how it works and what the different components are:
FREQUENTLY ASKED QUESTIONS:
What is a resonator, and do I need one?
A resonator is critical for a street-driven car. Here are some basic, layman's terms explanations:
There are 3 common ways to reduce sound in an exh system: Resonator (reflected waves), muffler (wave absorbtion and reflection) and silencer (reflected waves and restriction). BRM uses a resonator and a straight-through muffler on its systems for the S13 and S14.
Resonator is a straight-through chamber sized larger than the inlet / outlet, sometimes with baffles or slots (think old-school cherry bombs). Tuned properly (through placement, diameter, length, shape and location) it will actually cancel out certain frequencies as the sound waves collide, yet does not impede flow.
Muffler is a chamber with internal walls (think of a maze) that the gasses travel through. As the waves pass through, they are disrupted and "chopped up" and the sound is absorbed by the surrounding packing (think of an insulated room). Can be restrictive depending on design - if it's a straight-through design, it will not impact flow and actually makes very little impact on the sound (primarily "fine tunes" the exhaust note).
Silencer is a conical obstruction placed in the exhaust system which reflects sound waves back against themselves, cancelling certain frequencies, much like a resonator. But it also works by restricting the amount of flow, thereby reducing sound levels. May as well shove a potato in your tailpipe and bore a small hole in it.
What size should i get?The most commonly-asked question by far... Short answer - The KA and SR both function VERY well with 2.5" exhaust. Many will tell you that a turbo car needs a 3" exhaust to function properly, to which we say, NOPE.
Keep in mind that 2.5" is a significant increase in size over the stock system, and there are far less bends / restrictions in our system. Unless you're pushing 400+ hp, there's really no need for 3". However, we understand that some folks prefer a larger pipe diameter, so if that's what you want, then we'll build it for you!