What is a resonator, and do I need one?
A resonator is critical for a street-driven car. Here are some basic, layman’s term explanations:
There are 3 common ways to reduce sound in an exhaust system: Resonator (reflected waves), muffler (wave absorption and reflection) and silencer (reflected waves and restriction). BRM uses a resonator and a straight-through muffler on all of its systems.
A resonator is a straight-through chamber sized larger than the inlet / outlet. 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.
So, which one to choose? Typically, the longer resonator offers a somewhat deeper tone. While the difference in sound between the 22″, 18″, and 14″ resonator is minimal, it really comes down to personal preference. A longer resonator produces a deeper tone, which will also register as quieter. If you’re having a hard time deciding, go with the 18″ resonator… we’re confident you’ll be pleased with the sound and performance!
[NOTE: Some may recall that we used to offer a longer resonator for 3″ systems. Magnaflow no longer manufactures these. However, be assured that the redesigned 14″ resonator performs just as well as the old-style 18/22″ resonator, fits better, and weighs less.]
A muffler is a chamber with internal walls (think of a maze) that the exhaust 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). These can be restrictive depending on design – if it’s a straight-through design (which we use), it will not impact flow, and primarily serves to “fine tune” the exhaust note.
We don’t sell mufflers, resonators or components individually.
Some systems on the market are manufactured to use a silencer. A 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. BRM does not sell systems with silencers. You may as well shove a potato in your tailpipe and bore a small hole in it. If you’re considering a system with a silencer, do yourself a favor – Save your money and keep your stock system.
What size tubing should I get? The most commonly-asked question by far… Short answer: Nissan 4-cylinder engines 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, not necessarily true.
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, or more than 12psi, 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!
Should I order stainless or aluminized steel? The best way to determine this is to consider your location. If you live someplace where the roads are salted in the winter, or near the ocean, order the stainless. Another way to decide – Look at cars in your area – If their exhaust is rusting off after 5-7 years, order stainless. Otherwise, you’ll do just fine with an aluminized steel system (which is what is used on most new cars).
We use 409 stainless. We don’t polish our exhaust like the cheap imported systems you see on ebay – There’s no reason for it, and it’s actually indicative of a lower-quality steel. 409 stainless will develop a patina rapidly, especially if you’re near the ocean, or anywhere they salt the roads. 409 stainless is not made to be aesthetically beautiful but it will last – you’ll lose the car to corrosion long before the catback ever has issues.
In other words, it’s ugly, but it’s solid – you can test this by hitting it with some steel wool (there won’t be any pitting, like you’ll see on a rusted stock exhaust system). Here’s a better explanation by people smarter than me: http://www.summitracing.com/expertadviceandnews/professoroverdrive/answer/3932
GASKETS / HARDWARE
All gaskets and hardware that you’ll need to install your system will be provided. We recommend replacing your rubber hangers if they’re stiff, dry or brittle. Those are not included, but can be purchased at most local auto parts stores for a few dollars.
Typically, we’re averaging 8 days from the date of your order to delivery. Sometimes we’re quicker, sometimes we’re not. If at 8 days you don’t have your package, please let us know. There’s simply too much email flying back and forth to provide everyone with updates before 8 days. I’d love to do more, but this operation is a one-man show, and we operate on a shoestring budget. If you have special delivery circumstances or instructions, please email us when you place your order.
Lastly, thank you for supporting an independently-owned business and American-made products!