Resonator Removal Question

"Some cars, especially luxury cars where quiet operation is a key feature, have another component in the exhaust that looks like a muffler, but is called a resonator. This device works just like the resonator chamber in the muffler -- the dimensions are calculated so that the waves reflected by the resonator help cancel out certain frequencies of sound in the exhaust."

So how exactly did anyone come up with the conclusion that the air passing through the resonator travels straight? Keep your home mechanics opinions/theories to yourself and do research. Obviously if the resonator just passed flowing air straight through it would not be bulbous in appearance now would it??
 
714ms3 said:
"Some cars, especially luxury cars where quiet operation is a key feature, have another component in the exhaust that looks like a muffler, but is called a resonator. This device works just like the resonator chamber in the muffler -- the dimensions are calculated so that the waves reflected by the resonator help cancel out certain frequencies of sound in the exhaust."

So how exactly did anyone come up with the conclusion that the air passing through the resonator travels straight? Keep your home mechanics opinions/theories to yourself and do research. Obviously if the resonator just passed flowing air straight through it would not be bulbous in appearance now would it??
Click to expand...

The air travels straight because we (at least I) have looked closely at the resos when doing the DP/RP upgrade.

These are not the type of resos you describe on luxury cars. These are, indeed, "tuned" to attenuate specific frequencies to help with the notorious drone that four cylinder turbo engines have in the 2500 rpm range and also to produce a particular sound to the exhaust that the Mazda engineers were seeking, probably based on focus group feedback.

But, make no mistake, these resos are compact straight through designs. The inner tube is straight and constant diameter of 2.8 inches. There are a number of very small holes in that straight inner tube to allow the exhaust column to come into contact with solid sound absorbing material in a larger cylinder shaped outer chamber that is specific in dimensions. The outer chamber absorbant material is also chosen to selectively attenuate the frequencies specified. They are made the same way as other performance resonators and do not have internal baffles.

Here is an aftermarket example of the type of resonator Mazda employs, the Vibrant:

http://vibrantperformance.com/catal...d=292&osCsid=7f1842c9b740be199811d0f9240abdbc

I needed a third reso, so I used this:

http://vibrantperformance.com/catal...id=47&osCsid=7f1842c9b740be199811d0f9240abdbc

I personally installed the Vibrant 3" Ultra Quiet Reso in the middle of the RP section of my DP/RP to further tame the drone.

The Vibrant is just a larger variation of our stock resos.

With respect, it might be good not to call some of us "home mechanics" without knowing what we might do for a living, and perhaps posters seeking to criticize others might consider doing a bit of research themselves about performance resonators.
 
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I'm definitely not angry, and did not mean to insult anybody by calling them a home mechanic. I did research into the fact because I was sick of people posting opinions. The earlier posted quote is from howstuffworks, and I read up about the vibrant resonators, but I highly doubt that Mazda used high performance resonators on the stock exhaust. I also had the pleasure of looking at my resos when they were removed, and yes, they are full of holes for air to move through. So I pose this question to some of the skeptics: Would an intake tube with tiny holes in it out-perform an intake with no holes in the tubing? Obviously not. The same principle applies to our exhaust.
Do not get me wrong. I am not saying that there is a huge increase in performance, but there is some.
 
We've probably beat this to death. I apologize to the readers if we drone (pardon the pun) on a bit more.

Hypothetically, if there are small holes in a straight through pipe, and those holes lead to a larger chamber that is completely filled with a solid substance, and, hypothetically if that solid substance does not permit gas to pass through it, but does absorb sound, then does this reduce air flow?

I think the answer is no. That's the way our bottle resos are made.

But more importantly, if the straight through reso flows enough exhaust to allow the engine to produce over 300 whp with other mods, which our CBE does, then does it really matter how much MORE the reso might flow if it had no holes unless you are producing over 300 whp?

I think this is where we are in the debate. When the engine is capable of going over 300 whp, then the answer is to increase the diameter of the piping to 3 inches all the way through.
 
What is the size of the piping where the resonators are? I found a shop that would do this, but they told me to buy my own piping!?! Makes no sense to me, but whatever.

Gmac
 
It's a somewhat odd size. Larger than 2 3/4 inches, smaller than 3 inches. 2.800 I believe. That's the size of the stock exhaust all the way through.

There are threads and stickies about that here.
 
MSMS3 said:
It's a somewhat odd size. Larger than 2 3/4 inches, smaller than 3 inches. 2.800 I believe. That's the size of the stock exhaust all the way through.

There are threads and stickies about that here.
Click to expand...

Yah. The dude at the exhaust shop spent like 20 mins trying to find the correct size pipe. All in all, I was out of there in about 1 hour, and I am definitely pleased with the results.
 
So just got rid of the resonators. I like it! Cost me $140, not bad at all considering all of the work I had them do.

I had them cut in front of one resonator and behind another so I could keep the piping in between and put flanges on each end. Then with the straight piping they put in they put another set of flanges on.

Basically I can swap between the resonatorless piping and the stock piece with ease.

Sounds good, but not to stir the pot again I feel no real increase in torque or power. Sorry, I wanted to though.

Gmac
 
I had it done at Minute Muffler and Brake. Cost like 60 bucks. Not much louder at all with one resonator gone, most of the different is heard outside the car. Sounds throatier. No power difference- the shop guys even told me you will get no gains since its all straight through anyhow. So its all just tuning for the sound you want.
 
LukeP said:
No power difference- the shop guys even told me you will get no gains since its all straight through anyhow. So its all just tuning for the sound you want.
Click to expand...

Yeah, they got a good look at the resos. Go for the sound you like. These type of resos do not affect power unless you are exceeding their CFM flow rate, which we will not with the K04 turbo we have.

I like the idea of the poster who spent a few bucks extra to put those flanges on there so he can change back and forth.
 
MSMS3 said:
I like the idea of the poster who spent a few bucks extra to put those flanges on there so he can change back and forth.
Click to expand...

Yup, just took the stock piece out of the car and hung it in the garage. Though I love the sound, if I happen to be taking a long road trip I'll most likely take the twenty minutes to put the stock piece back on.

Gmac
 
just threw a TP in with my two resonators gone before the "muffler," gives the sound like you added a DP some what

the sound is more thurderous, boomy, bold. that sound you feel in your chest its so deep. love love love
 
im considering doing this soon but am wondering if mazda will try to void my warranty for this. has anyone had issues with their warranty after removing the first 2 resonators? i would love some sound from the exhaust but not if its going to give me a headache at the dealership if i need something done. i know it doesnt add power or change anything but the exhaust note but seems like car companies will void you for anything now.
 
Jackyll said:
im considering doing this soon but am wondering if mazda will try to void my warranty for this. has anyone had issues with their warranty after removing the first 2 resonators? i would love some sound from the exhaust but not if its going to give me a headache at the dealership if i need something done. i know it doesnt add power or change anything but the exhaust note but seems like car companies will void you for anything now.
Click to expand...
nope,
no issues

they cant void for you messing with the CBE. not like you are changing the TP.

take out both resonators before the muffler. you will love it
 
240ka said:
nope,
no issues

they cant void for you messing with the CBE. not like you are changing the TP.

take out both resonators before the muffler. you will love it
Click to expand...

they can void your warranty.....the try to void mine so i left and came back with resonators welded back
 
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