Curing Muffler Drone - what muffler choice?

Dennis H

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No hint of drone. Dynomax Superturbos behind TTI’s. Also behind the QTP’s. No resonator.
 

Gary Jenkins

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Walker Quiet Flow - 21856. They are 2.5" offset inlet, 2.5" centre outlet and 23" overall length. This muffler is aluminised steel construction not SS. I could not find a SS version with these dimensions. The rest of my exhaust system is not SS so wasn't worried about getting SS mufflers. (went with these mufflers as the stock hemi/440 mufflers I found were 2.25" in and out and a bit longer overall so not quite a direct fit for my application)

I also found a Walker Sound FX with the same dimensions - have misplaced that part number. I could dig it up again if you want it Gary. The local muffler shop suggested the Quiet Flow over the Sound FX from a construction and durability perspective.

The construction of these mufflers is such that the inlet and outlet tubes decrease in diameter fairly significantly for part of the tube length. You can see this on the cutaway views of the muffler available online - Walker website and others. I could see this when I looked down the tubes in an out of the mufflers before they were put on. Whether or not this affects back pressure significantly or not, I have no idea. Driving the car I can't tell the difference - except that now I don't need hearing protection, which was my goal... :) Thought I would point this out as many online reviewers seemed surprized/angered by this when they received their purchase.

I found the Walker website difficult to navigate and their filters hard to use. I found this part number using the screener on a popular performance parts supplier website.

Good luck
I see Rock Auto show the SoundFX 18230 on their site any feedback on this?. just no one in New Zealand stocks walker and Rockauto ship at good prices, so for less that on resonator here I could get 2 mufflers
Actually Amazon ship cheaper by almost 1/2 of rockauto
anyone got any feedback on the 18230
thanks
 

73LemonTwist

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I see Rock Auto show the SoundFX 18230 on their site any feedback on this?. just no one in New Zealand stocks walker and Rockauto ship at good prices, so for less that on resonator here I could get 2 mufflers
Actually Amazon ship cheaper by almost 1/2 of rockauto
anyone got any feedback on the 18230
thanks
The SoundFX I was looking at was the 18261 because I wanted 2.5" in/out and 23" overall (the 18230 is 2.25" in/out and longer than the space I had in my piping - if memory serves the 18230 came up as the suggested stock replacement for hemi and 440 cars on the Walker website). The 18261 SoundFX muffler has a case length of 16" whereas the Quiet Flow I purchased has a 19" case (both are 23" overall). Everything I have read suggests longer the muffler, quieter it will be. My muffler shop said either would work and he suggested the Quiet Flow option as it should be more durable and quieter. At the time I bought mine Rock Auto and Summit both had these options in stock.
 

Gary Jenkins

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The SoundFX I was looking at was the 18261 because I wanted 2.5" in/out and 23" overall (the 18230 is 2.25" in/out and longer than the space I had in my piping - if memory serves the 18230 came up as the suggested stock replacement for hemi and 440 cars on the Walker website). The 18261 SoundFX muffler has a case length of 16" whereas the Quiet Flow I purchased has a 19" case (both are 23" overall). Everything I have read suggests longer the muffler, quieter it will be. My muffler shop said either would work and he suggested the Quiet Flow option as it should be more durable and quieter. At the time I bought mine Rock Auto and Summit both had these options in stock.
Thanks. all are available to me on amazon, so will look into that next month or so
 

Voetom

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I have a stock '73 340 RR with custom bent 2.5" exhaust with X pipe (still using stock cast exhaust manifolds). I am having trouble finding a muffler that suits my ears. I have tried the Dynomax VT - wonderful sound at idle and no drone, but just too loud on the highway when its running straight through. So, tried the Dynomax Super Turbo. Quieter for sure, but it droned at 1500/2500/3500 rpm - especially when coming off the throttle. So now I have Flowmaster Delta 50 mufflers on the car. When not droning, they are reasonably good sound level. However they hit massive resonance peaks at 1200/2000/3000 rpm, especially when decelerating. My old ears can't take these peaks and they occur around your typical cruising speeds.

The mufflers are located in the same location as stock, just ahead of the rear end. The Xpipe is located under the tail end of the auto trans.

Suggestions on what to try next? I would like to have some of the old school rumble, but if I have to go super quiet, that would at least make the car more pleasurable to drive. Maybe have to go back to a tube/baffle style muffler?

Thanks...

Allan
73, on my pal's 400 4 barrel 72 Satellite Sebring we used 2.5" Imposter mufflers from Waldron. They rumble a bit but don't recall a drone issue. they are basically an opened up stock muffler.
 

1STMP

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I love the rumble of a rarely named muffler.
Bassani. I have them on all three of my
vehicles.
 

Ron H

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Hey Ron,
Tried recording a sound byte from my
phone. Sounded like crap.
Found one on YouTube-

THANKS. Yep, sounds awesome.
 

gtxrt

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quiet flow, flow is not bad. fx are louder and flow not as good. Borla XS are the best if want the best performance, there louder but no drone
 

68 Sport Satellite

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The most elegant solution is a Helmholtz resonator. (Google it). But they take some fabrication, and some calculations that lots don't want to do. And Flowmasters are also known as dronemonsters.
If you don't want to change mufflers again, and if you have room along side the gas tank, I would try either specific resonators, or small glasspacks used as resonators.
If you don't have the room for add on glasspacks, I would go with the biggest walker quiet power that will fit under the car.
I added a Helmholtz resonator setup to my car and it works great. I run Dynomax Ultraflow Welded and with the HR setup, no drone and nice exhaust note. I like the sound of the Dynomax Super Turbos better and those are quieter, but the Ultraflow welded has noticeably less restriction I can feel when driving.

The Helmholtz resonator setup I added I wish I would have tried the short length round cans, but at the time I copied something I had read some other brand cars had done in the past and used a piece of 2.5" diameter exhaust pipe like the rest of my exhaust and ran it on each side for a length of 28" and capped at the end. The sound waves enter that length of pipe and bounce back, cancelling some drone. I wasn't sure it would work until I tried it. It sure looks funny under my car though. I may modify it some day for a bit cleaner look and try the shorter cans or just go with Super Turbos. I'll see if I can find some photos to post.
 

Gary Jenkins

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The SoundFX I was looking at was the 18261 because I wanted 2.5" in/out and 23" overall (the 18230 is 2.25" in/out and longer than the space I had in my piping - if memory serves the 18230 came up as the suggested stock replacement for hemi and 440 cars on the Walker website). The 18261 SoundFX muffler has a case length of 16" whereas the Quiet Flow I purchased has a 19" case (both are 23" overall). Everything I have read suggests longer the muffler, quieter it will be. My muffler shop said either would work and he suggested the Quiet Flow option as it should be more durable and quieter. At the time I bought mine Rock Auto and Summit both had these options in stock.
Hi,
Well no wonder mine drones like crazy the current set up is only 13" so even the (18261) replacement Walker at 23"would be a big improvement. trouble is that freight kills most stuff to downunder, its almost 200$ dearer to get the (21856)'s here
 

gtxrt

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tech at walker exhaust even said that the big dynomax super turbo do drone, there the ones that come with the tti exhaust, but they do flow good.
 

68 Sport Satellite

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I added a Helmholtz resonator setup to my car and it works great. I run Dynomax Ultraflow Welded and with the HR setup, no drone and nice exhaust note. I like the sound of the Dynomax Super Turbos better and those are quieter, but the Ultraflow welded has noticeably less restriction I can feel when driving.

The Helmholtz resonator setup I added I wish I would have tried the short length round cans, but at the time I copied something I had read some other brand cars had done in the past and used a piece of 2.5" diameter exhaust pipe like the rest of my exhaust and ran it on each side for a length of 28" and capped at the end. The sound waves enter that length of pipe and bounce back, cancelling some drone. I wasn't sure it would work until I tried it. It sure looks funny under my car though. I may modify it some day for a bit cleaner look and try the shorter cans or just go with Super Turbos. I'll see if I can find some photos to post.
Here’s my setup. Strange looking but it works.

9B0ED187-36E5-4732-944A-F25A6A97DEB1.jpeg


A4DFE81A-4582-4D53-B30F-A35B21A2E3DB.jpeg
 

33 IMP

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That's perfect, that's how it's done! Did you do the calculations to come up with a length, or just try what you had, to see if it worked?
Nicely done, the best solution, in my opinion.
 

68 Sport Satellite

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That's perfect, that's how it's done! Did you do the calculations to come up with a length, or just try what you had, to see if it worked?
Nicely done, the best solution, in my opinion.
I had read an article on it and it said that 28" length was ideal to cancel the audio wave. I don't know if this is universal and I can't recall the original article it was so long ago.

By the way, I have an H-pipe connection in front of where these resonator pieces are welded in.
 

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