Muffler Too Loud

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dhenderz
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Muffler Too Loud

Postby dhenderz » Wed Sep 14, 2011 5:01 pm

OK, got a question. I have a Walker 'sound FX' muffler on the Q4 GTZ. Nothing special, just ordered right off the RA web site. It was fine until I pulled the cat and replaced it with a flow through pipe. Now the exhaust is too loud & too raspy. I wake the neighbors up in the morning leaving for work.

I need to find something quieter, but ideally not Buick quiet. So, do any of you have a recommendation that you've tried (or presently have installed) on a Q4 without a cat?


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Re: Muffler Too Loud

Postby uncle » Wed Sep 14, 2011 6:35 pm

A cat and a resonator in combination with a muffler is the only way to quiet these things down. A guy on Q4F was running two mufflers if I remember correctly, but I don't recall how he rigged that up. I know mine is way loud with the header, cat, muffler - and I want to eventually get a resonator or something installed eventually because I feel the same way about my neighbors when I leave early in the morning.


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Re: Muffler Too Loud

Postby Barry » Wed Sep 14, 2011 7:42 pm

You could put a small resonator where the cat used to be. Unfortunately cats do a great job of killing raspy stuff.



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Re: Muffler Too Loud

Postby SuzukiGhostRider » Wed Sep 14, 2011 8:05 pm

Get rid of the straight pipe and put a 22" or better glasspack in it's place. You will find this will quiet it down considerably , get rid of the raspy, and retain the added throttle response and slight power gain.


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Re: Muffler Too Loud

Postby berettaboi » Wed Sep 14, 2011 9:45 pm

i'm not sure what studies show, if a 'high flow' cat is actually high flow... but i'm kinda a half ass tree hugger, so i would keep one in the mix just for my piece of mind.


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Re: Muffler Too Loud

Postby Chad91GTZ » Wed Sep 14, 2011 10:17 pm

A quad doesn't need a catalytic converter to be environmentally friendly. It gets 30+ mpg on its own.

The only solution I've heard of working is the resonator in place of the cat, but I've yet to find a combination that doesn't rice out after 3 to 3500 rpm.


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Re: Muffler Too Loud

Postby weba » Thu Sep 15, 2011 2:55 am

I have 3 mufflers on my Quad and it's still louder than anything out there. Quad is really hard to tone down, add in big tube headers and pipe, you can challenge a helicopter for noise level.

I haven't ever heard a decently quiet Quad Without cat .



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Re: Muffler Too Loud

Postby 3X00-Modified » Thu Sep 15, 2011 8:12 am

This is quite possibly the reason why... I pulled this from www.overboost.com just so people know.
Types of Muff
Mufflers can take care of the silencing chores by three major methods: Absorption, Restriction, and Reflection. Mufflers can use one method, or all three, to attenuate sound that is not so pleasing to the ears of the Highway Patrol.

The absorption method is probably the least effective at quelling engine roar, but the benefit is that "absorbers" are also best at letting exhaust gas through. Good examples of absorbers are the mufflers found in GReddy BL-series exhausts, DynoMax UltraFlow, and the good old-fashioned Cherry Bomb glasspack.

Absorption mufflers are also the simplest. All of the above named mufflers utilize a simple construction consisting of a perforated tube that goes through a can filled with a packing material, such as fiberglass or steel wool. This is similar to simply punching holes in your exhaust pipe, then wrapping it up with insulation. Neat, huh?

Another trick absorption mufflers use to kill off noise is, well, tricky. For example, the Hooker Aero Chamber muffler is a straight-through design, with a catch. Instead of a simple, perforated tube, there is a chamber inside the muffler that is much larger than the rest of the exhaust pipe. This design abates sound more efficiently than your standard straight-through because when the exhaust gasses enter this large chamber they slow down dramatically. This gives them more time to dwell in the sound insulation, and thus absorb more noise. The large chamber gently tapers back into the smaller size of your exhaust pipe, and the exhaust gasses are sent on their merry way to the tailpipe.

Restriction
Doesn't that word just make your skin crawl? It's right up there in the same league with words like "maim" and "rape".

Obviously, a restrictive muffler doesn't require much engineering expertise, and is almost always the least expensive to manufacture. Thus, we find restrictive mufflers on almost all OEM exhaust systems. We won't waste much time on the restrictive muffler except to say that if you got 'em, you might not want to flaunt 'em.

Reflection
Probably the most sophisticated type of muffler is the reflector. They often utilize absorption principles in conjunction with reflection to make the ultimate high-performance silencer. Remember any of your junior high school math? Specifically, that like numbers cancel each other when on a criss-cross? That's the same principal used by the reflective muffler. Sound is a wave. And when two like waves collide, they will "cancel" each other and leave nothing to call a corpse but a spot of low-grade heat.

There are numerous engineering tricks used in the reflective muffler. Hedman Hedders makes a muffler that looks a lot like a glasspack. In fact, it is a glasspack with a catch. The outer casing is sized just-so, so that high-pitched engine sound (what we deem "noise") is reflected back into the core of the muffler… where those sound waves meet their maker as they slam right into a torrent of more sound waves of like wavelength coming straight from the engine. And, this muffler is packed with a lot of fiberglass to help absorb any straggling noise that might be lagging behind.



So the best way to muffle something is by a bit of restriction unfortunately...

And typical miss information regarding a resonator.

Resonators
On your typical cat-back exhaust system, you'll see a couple of bulges in the piping that are apparently mini-mufflers out to help the big muffler that hangs out back. These are called Helmholtz Resonators and are very similar to glasspacks. The main difference is that firstly, there is no sound-absorbing fiberglass or steel wool in a Resonator. And secondly, their main method of silencing is the reflective principle, not absorption. An easy way to tell the difference between a glasspack and a true Helmholtz Resonator is to "ping" one with your finger. A glasspack will make a dull thud, and a true Resonator will make a clear "ping!" sound.



Check a stock 3100 resonator, its a big 4-5" bulge and all thats in it is ONE plate in the middle with a 2" hole in the center of it... No glass packing at all. I'm tempted to install that on my car just to bring the noise down a bit.



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Re: Muffler Too Loud

Postby woody90gtz » Thu Sep 15, 2011 3:38 pm

Dynomax VT...quiet at idle and light cruise, but still loud at WOT.


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Re: Muffler Too Loud

Postby DTMAce » Thu Sep 15, 2011 11:11 pm

dhenderz wrote:OK, got a question. I have a Walker 'sound FX' muffler on the Q4 GTZ. Nothing special, just ordered right off the RA web site. It was fine until I pulled the cat and replaced it with a flow through pipe. Now the exhaust is too loud & too raspy. I wake the neighbors up in the morning leaving for work.

I need to find something quieter, but ideally not Buick quiet. So, do any of you have a recommendation that you've tried (or presently have installed) on a Q4 without a cat?


Sorry, but this got me thinking about having a beretta that was silent but deadly!! LOL

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Re: Muffler Too Loud

Postby SuzukiGhostRider » Fri Sep 16, 2011 12:17 am

I am telling you (through personal experience) that if you do what I said with a glass pack of the size mentioned, it WILL return it VERY close , if not dead on, to factory noise level.


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Re: Muffler Too Loud

Postby 90GTZHO » Fri Sep 16, 2011 2:21 am

I have to chime in here, im sorry.

Coming from a person who ran for over a year without a cat on my car, put the damn thing back on. Quads sound like crap without a cat. There is nothing you can do to make it sound any better than it does with a cat installed. Plus, with my cat removed back in the day (and no other mods done), i got 32 on the highway at best; with the cat back on, i did a best of 39mpg. Do yourself a favor, and install atleast a shorty Magnaflow cat and call it a day.

I dont get why people remove cats from their quads then complain about the noise....*facepalm*


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Re: Muffler Too Loud

Postby SuzukiGhostRider » Fri Sep 16, 2011 4:22 pm

My mileage was about the same either way. Cat doesn't really seem to affect mileage wso. Not quite sure why you noticed BETTER mileage with a Cat Geoff, but that sounds strange to me....


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Re: Muffler Too Loud

Postby dhenderz » Sat Sep 17, 2011 7:43 am

Guys - thanks for the info. Will head down the path of a flow thru glass pack in the place of the cat.

As to why the cat was removed? Simple, it was shot. Not spending the extra coin for a new cat on a car that is headed to the crusher in the next 6 - 9 months. The flow thru pipe was $7.

As for the mileage difference, sorry I don't buy it. A cat does not impact mileage. If you saw a mileage difference then you had other differences in the system or calc'd something wrong. If you have found a way to get a 22% improvement in MPG with your cat installation you should market it to the OEM's. You'd be rich!


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Re: Muffler Too Loud

Postby SuzukiGhostRider » Sat Sep 17, 2011 2:14 pm

Agreed, Dennis. I've NEVER heard of a Quad pulling 39mpg either. I think you made a slight miscalculation there Geoff ol' boy. :P


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