Removing the resonator -Pros, Cons & Advise

[FrankCastle]

I know this thread spans over some time, but I wanted to put in my $.02, for the next person who searches.  I had a Magnaflow muffler #12229 (single in, single out, 14") put on, and originally left the resonator on.  It sounded good, for the $100 I spent, but I was curious about how much better it might sound without the resonator, and would that add drone at highway speeds?  Well, I recently took the plunge and had the resonator cut off (but I kept it, just in case) and a stainless steel tip put in its place.  I am beyond thrilled with the low growl that I get in town, coupled with the fact that at highway speeds there is no noticeable drone.  Radio off, on the cell phone is the best test for me.  I even put it to the test with the windows all open, in town, with my wife in the truck trying to talk to me.  Not only were we able to talk, but she LOVED the sound of the truck. 

I couldn't be happier with the Magnaflow.  I couldn't be happier without the resonator.  All for a grand total of $200.

[Frank07]

OK...finally removed the resonator.  Sounds awesome.  Just enough growl with the FM 50.

[avalonandl]

I believe Travelingman had this done to one of his AV's in TN.  I don't recall there being a problem and I thought it did give it a "close to flowmaster" sound.

On the flip side of that, a few weeks ago I had new tires put on and asked the shop to price me a flowmaster catback system ($700).  I made the comment of just cutting off the resonator.  They said it would mess up the 02 sensors and make the check engine light remain on.

I'm doubting this but yet it stopped me from breaking out the sawzall   

That is crap, resonators will have NO effect on O2 sensors- they mean the catalytic converter.


Avalon

[muffman]

Good call Avalon on the O2 Sensor, you are absolutely correct.  I just removed the whole system on my 2010 LTZ yesterday, installed the single in, dual out Magnaflow 5 x 8 x 24 with two 2 1/4 inch tailpipes.  The AV has a nice smooth sound now, absolutely no resonation or droan, and seems to have a little better throttle response.  I may try the 18-inch next week to see what the difference is.  I'm baffled (no pun intended)  by the use of the resonator on the stock system, I really don't see the need.  I noticed on the 2010 the addition of a third catalytic converter compared to my 03.

I certainly wouldn't hesitate to cut off the stock resonator.

Muff

[Frank07]

I cut my resonator out in June.  No issues whatsoever.

[avalonandl]

Muffman- The resonators were primarily installed to handle the DOD  (displacement on demand) resonance  and overall noise reduction. When the V8 goes to V4 there can be low Hz resonance that is annoying- remember this is at highway speeds only. The Pontiac G8 has an enonomous amount of mufflers and resonators to handle this on the 6.0 V8- way more than necesary.

Avalon

[muffman]

Avalon,

I'm fully aware why the "resonator" (not resonators) were added to the AV.  However, in my testing, I find this to be overkill.  This resonance is easily eliminated by implementing two smaller diameter tailpipes, rather than one larger tailpipe, and the use of the proper performance muffler.

DOD or not, the 6.0L motor has always had much worse resonation than the 5.3L.

Muff

[black_magic]

Avalon,

I'm fully aware why the "resonator" (not resonators) were added to the AV.  However, in my testing, I find this to be overkill.  This resonance is easily eliminated by implementing two smaller diameter tailpipes, rather than one larger tailpipe, and the use of the proper performance muffler.
DOD or not, the 6.0L motor has always had much worse resonation than the 5.3L.

Muff

So, what you are saying is two exhaust tips will be quieter INSIDE than a single 3"?  Good stuff!  I was actually under the impression that the dual tips would actually be louder.  Learn something new everyday.  Does the muffler need to be a dual out muffler or can somebody who already has a single-out muffler add a "Y" to their system to help with the drone?

[JLUTTY3]

I have an 07 Avalanche with a 5.3. I drive 12, 14, or 17 hours at a time 8x a year, and take it on sales calls. My truck is a weekend warrior/ grocery getter most other times.

"Everybody" says the stock, quiet muffler can is keeping me off 2 more mpg on those long highway trips. 

I am about to install a clean tube to the air box and an aftermarket element.

I am thinking of putting on a 22" magnaflow for mileage and a slightly deeper tone AND keeping the resonator tip to reduce noise fatigue during the long highway trips. I love the growl. I hate the interior resonance.

My question is, what is the design of the resonator? Is it a pass-through perforated tube with wadding around it, or a baffled chamber?

This would answer my question about flow. I would like to keep it if it's just a pass through. if it's not, I might end up going with turbo- style muffler and no tip.

[FrankCastle]

My exhaust guy (owned an '07 Av himself) said the resonator, whether on, or off, would have no measurable effect on mileage or performance, to speak of. He said it would only give a little more sound. I commute daily in my '07 5.3 and maintaining 80mph with my 14" Magnaflow, I have no resonance in the cab. My $.02

[JLUTTY3]

My exhaust guy (owned an '07 Av himself) said the resonator, whether on, or off, would have no measurable effect on mileage or performance, to speak of. He said it would only give a little more sound. I commute daily in my '07 5.3 and maintaining 80mph with my 14" Magnaflow, I have no resonance in the cab. My $.02

Did your exhaust note change? Is there a video of what yours sounds like right now on line?

Thanks for the reply!

[FrankCastle]

It got a little louder, maybe deeper. I had left it on for a while, but just wanted more growl. I was very ploeased with the final product. I don't have a video up of it. I didn't want to use a cell phone to do it and done have a decent video camera for that.

[speedysteveabz]

I just cut off the resonator and added the SLP dual exit tip ( as many have done ) mostly for the cosmetics as I too hated that ugly resonator, the sond difference is as has been stated very slight and from inside the cab I cannot notice a difference at all, outside the vehicle a very slight increase in volume and sounds a little more "burbly" which is good.

I am seriously considering a tune from either blackbear or nelson and am wondering if a muffler change would make any significant difference and whether it should be done before the tune, I dont want a shouty noisy truck but would be willing to tolerate a little more volume if it would have a noticable effect on performance.

I know everyone seems to think changing the muffler will improve performance I just wonder if its all in the ears rather than at the wheels 

SS

[Vaeagleav]

I have never bought a tune for my AV but I'm not racing or trying to squeeze out the last ounce of HP or torque either. You would have considerations like are you looking for top rpm power or low to midrange torque etc. speedysteveabz.......
I would contact the tune company I or my mechanic is comfortable with and see what the company says is best way to go and listen to them since they have done all the testing already.
I'm sure most owners will tell you they got an increase in performance but that could be just a way to justify their decision in their minds since most owners don't put their mods on a dyno for hard numbers.
I have been a member and AV owner for 10 years and in my experience and reading I feel the stock muffler does bog down the 5.3 motor. When I changed to a Corsa Sport cat back setup in my 2004 and my 2008 AV it seemed to accelerate quicker by my "butt dyno".  Corsa does claim a h.p. and torque increase and they do lots of research and development which I don't care to replicate. As far as sound I love the Corsa and it is famous for NO DRONE in the cab.
I would replace the muffler before a CAI or a tune myself and if I was looking for maximum USABLE power and torque in a 5.3 I would save my money and get a Magnacharger supercharger kit. Just my .02 though.

[enoniam]

A muffler change shouldn't affect a custom tune very much, but if you are thinking of doing both now I would do the muffler first.

[speedysteveabz]

Thanks Vaeagleav, supercharger kit would be great but im never gonna justify that kind of money to make my 3 ton "brick" go a little faster..
Im pretty sold on the validity of a tune based on the feedback here and on other chevy truck related sites + some positive experiences in the past with turbo subaru's and the tune cost is in the region of $300 which isnt excessive which seems like decent "bang for the buck" Ill do as you say and contact a couple of tuners for their opinions

SS

[Alwaysnosing]

I recently put on the Diablo intune on my 2007 5.3 Avalanche. The stock tunes contained on it make the drivability much more noticeable in my opinion. In fairness, the Avalanche is a voluptuous lady and moving down the road at a great rate of knots is not going to come cheap! lol I went for the intune as it can disable the AFM. I went from using 2-3 quarts between oil changes down to 1. The recommended modification / change from the factory was a splash guard i believe within the oil system. Disabling the AFM didn't affect my MPG's either, i drive up and down hills on street roads as opposed to freeway and i average 14-17mpg. When i do a long blast i can get over 20mpg, but i bought it for the AFM disabling function as well as to firm up the shifts.

I spoke with a reputable custom tuner and they advised me to get the exhaust, intake if i wanted one (i did the AFE pro dy drop in filter) then get the tune based upon the data logged using the intune module. So the tune is truly custom as opposed to the 'off the shelf' approach i am running with the intune. I run it on the 'economy' mode and moderate shift pressure. Makes a big difference in gear changes and makes the truck more responsive. I did run it for a week on the performance tune with premium gas, but didn't really see a big enough difference to cover the extra cost in gas, so the economy tune it is!

[redheadedrod]

Resonators are specially tuned mufflers. They are designed for specific frequencies and are for no other purpose. You can remove them and all you should have happen is your exhaust sound changes. If you change your muffler for something other than stock then the resonators really don't do anything anyhow unless the mufflers were designed with the resonators in mind.

Changing your exhaust should have no effect on the tune unless you start getting into headers, opening your exhaust ports, maybe a cam... You need to remove all of the restrictions in the system before it makes any difference on anything other than sound. Just putting on a bigger exhaust doesn't do anything for you.

Rodney