Re: Muffler drone, Please recommend for ones that dont!
[Re: Criterion]
#2301510
05/09/17 01:00 AM
05/09/17 01:00 AM
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Joined: Jan 2005
Posts: 3,699 Newport, Mi
Evil Spirit
master
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master
Joined: Jan 2005
Posts: 3,699
Newport, Mi
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E) Keep the exhaust the way it is and add a sound deadener if the resonance is from an actual panel, i.e. trunk floor, vibrating. This. In many cars, especially the ones with full tailpipes, the drone isn't from noise out the tails - it's noise resonating through the body of the muffler, then into the floor pan of the car. Since we tend to try to fit the largest mufflers under the car, and install them as close to the floor as possible, this tends to increase the possibility of an exhaust drone. To over-simplify - sound doesn't pass "through" the muffler body, the noise inside is sound pressure waves that flex the metal body, resulting in sound pressure waves that are created outside the muffler body, and are then transmitted to the floor pans, causing a drone. And yes, sometimes changing or adding mufflers can remove the drone, by changing the sound pressure waves in the system. But I've had better luck removing drone by insulating the body of the muffler than by changing them, or adding a resonator. I usually do a layer of header wrap covering the muffler body sides, a layer of 22 ga stainless sheet, and repeat for a total of 2 layers of each, holding them on with the metal header wrap straps. I've also used old welding fire blankets and hi-temp fiberglass sheet for the sound deadener. I can't guarantee this will fix every instance of exhaust drone - I'm just offering another method of eliminating it to consider that has worked well for me in the past.
Free advice and worth every penny... Factory trained Slinky rewinder.........
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Re: Muffler drone, Please recommend for ones that dont!
[Re: 451Mopar]
#2301562
05/09/17 02:41 AM
05/09/17 02:41 AM
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Joined: Jan 2003
Posts: 8,393 Highland, MI.
Sunroofcuda
master
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master
Joined: Jan 2003
Posts: 8,393
Highland, MI.
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I put Walker quiet flow SS mufflers on the convertible.
Walker 22154 Quiet-Flow Stainless Steel Muffler, but it really was too long to fit well (29").
The Walker #21498 quiet flow SS (fits a 2004-2006 Chrysler Pacifica) show s to be 2-1/2" in/out, and just $64 from summit racing, just have to cut off the welded on muffler hangers. These are smaller 13" long case mufflers 20" tip to tip. Says they are a turbo style muffler.
Looks like the outlet tube may be angle cut for the exhaust exit? It could be cut straight and swedged to connect to the tial pipes?
Found a picture of the 22154s on the convertible, these are long.. I'm trying to get a print of those mufflers from a buddy. I'm guessing they have 2" internal flow tubes. When I google the 22154, I don't see anyone carrying it anymore? Maybe it got discontinued? Internally, it might me 2-1/4"? I do think it is larger than 2", and I can still hear the exhaust. I'll have to get a video with sound for these mufflers. Last video of the car was with the Super turbo mufflers that came with the TTI exhaust. Well, I received the print showing the internals of these today. There are 2 flow tubes internally, both choke down to 2" just like I thought. There is no packing for any noise absorption, & the flow tubes are not perforated. These babies are long - 25" long shells. These are NOT real good-flowing mufflers from the way the print looks, but adequate for a passenger car.
No Man With A Good Car Needs To Be Justified
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Re: Muffler drone, Please recommend for ones that dont!
[Re: Sunroofcuda]
#2301769
05/09/17 02:48 PM
05/09/17 02:48 PM
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Joined: Jan 2003
Posts: 16,376
dogdays
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 16,376
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I didn't read the three p[ages of comments because the initial assumption is wrong.
Mufflers do not cause drone. The system causes drone. Similar to tuned headers or a tuned intake tract, the exhaust system has resonance and when the engine pulses excite that resonance, you experience drone. I've been in a few Men's rooms where it was easy to excite the resonant frequency by humming the right pitch. One I remember was at my old job, where the room was tuned to low "G".
So if mufflers do not cause drone, why do so many of these solutions work? Because they change the resonant point or else dampen the resonant peak's resonance to the point where it's not objectionable.
I suppose a louder muffler does have more of a tendency to drone, because the sound pressure (energy) is higher and more apt to resonate in an audible way.
Adding a crossover pipe or X-pipe can help too. I'd start there.
Dynomax Super Turbos 17748 and 17749 are my fvorites for 2 1/2" systems, if they fit. They are relatively quiet at idle or at low throttle pressure. With more power they take on more of an aggressive sound. I've received complimentws from strangers who tell me it sounds exactly right Upon startup, I was dismayed at how quite they were, but as the miles went by, they opened up a little.
So remember it's the system, not the mufflers.
R.
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Re: Muffler drone, Please recommend for ones that dont!
[Re: 4mulaS]
#2383281
10/07/17 02:42 AM
10/07/17 02:42 AM
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Joined: Jan 2006
Posts: 835 Alberta
4mulaS
OP
super stock
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OP
super stock
Joined: Jan 2006
Posts: 835
Alberta
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Just as an update, I ended up going with Accurate exhaust hemi repop mufflers, 2.5 in and 2.25 out. Drone MOSTLY gone. The range it used to really bother me in is gone but with the accurate stuff the drone does and can occur at a very low rpm. Thankfully I'm seldom in that range. On a side note, the sound freekin awesome!!! Sooooo many compliments and I really love it now too. The best part of the sound is at idle, very throaty, when you're on it and giving it full throttle they are respectfully quiet. Not a nuisance muffler.
Happy with the purchase
66Scar
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Re: Muffler drone, Please recommend for ones that dont!
[Re: bonefish]
#2383410
10/07/17 01:44 PM
10/07/17 01:44 PM
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Joined: Nov 2003
Posts: 36,040 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
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Sounds like everyone is happy/knows what to do
live every 24 hour block of time like it's your last day on earth
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Re: Muffler drone, Please recommend for ones that dont!
[Re: 4mulaS]
#2385776
10/11/17 05:56 PM
10/11/17 05:56 PM
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Joined: Jan 2003
Posts: 7,538 Albany, NY
67SATisfaction
The member whose name is actually Art
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The member whose name is actually Art
Joined: Jan 2003
Posts: 7,538
Albany, NY
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Just as an update, I ended up going with Accurate exhaust hemi repop mufflers, 2.5 in and 2.25 out. Drone MOSTLY gone. The range it used to really bother me in is gone but with the accurate stuff the drone does and can occur at a very low rpm. Thankfully I'm seldom in that range. On a side note, the sound freekin awesome!!! Sooooo many compliments and I really love it now too. The best part of the sound is at idle, very throaty, when you're on it and giving it full throttle they are respectfully quiet. Not a nuisance muffler.
Happy with the purchase Glad to hear - and you've kept the H-pipe, right? (I've got virtually the same setup as you used to have, 383/4bbl 2in H-pipe and FlowMasters with a wicked drone, but only right at 45mph.. so I just don't stay there much. Now I know what I'll do when it's time for a change.. but I think I'll drop the H-pipe too). Cheers, - Art
65 Satellite hardtop 361/4bbl console 727 2.76 67 Satellite convert 383/2bbl column 727 3.23 67 Lancia Fulvia Sport 1.3 Zagato. Alloy body, 1.3L V4 DOHC 4-spd 67 Lancia Fulvia Rallye 1.3. Alloy panel, 1.3L V4 DOHC 4-spd 71 Alfa Romeo GT Junior 1300 Zagato, 1.3L 4cyl DOHC hemi 5-spd 82 Alfa Romeo GTV6 2.5L SOHC hemi V6 5-spd transaxle 75 Maserati Bora US spec 4.9L DOHC hemi V8 5-spd ZF 77 Maserati Khamsin Euro spec 4.9L DOHC hemi V8 5-spd ZF 07 Aston Martin DB9 6.0L DOHC V12 6spd transaxle
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Re: Muffler drone, Please recommend for ones that dont!
[Re: 67SATisfaction]
#2391971
10/23/17 06:51 PM
10/23/17 06:51 PM
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Joined: Jan 2006
Posts: 835 Alberta
4mulaS
OP
super stock
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OP
super stock
Joined: Jan 2006
Posts: 835
Alberta
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Art, Yes I've kept He H pipe. Drone used to be real bad between 1700-2100 rpm. If I get some minor drone now it is around 1350-1400.
Do you think dropping the H improves that more?
Last edited by 4mulaS; 10/23/17 06:51 PM.
66Scar
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Re: Muffler drone, Please recommend for ones that dont!
[Re: 4mulaS]
#2392576
10/24/17 09:54 PM
10/24/17 09:54 PM
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Joined: Jan 2011
Posts: 4,785 Utah and Alaska
astjp2
master
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master
Joined: Jan 2011
Posts: 4,785
Utah and Alaska
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Are you opposed to using resonators?
1941 Taylorcraft 1968 Charger 1994 Wrangler 1998 Wrangler 2008 Kia Rio 2017 Jetta
I didn't do 4 years and 9 months of Graduate School to be called Mister!
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Re: Muffler drone, Please recommend for ones that dont!
[Re: 4mulaS]
#2393151
10/25/17 11:42 PM
10/25/17 11:42 PM
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Joined: Jan 2003
Posts: 7,538 Albany, NY
67SATisfaction
The member whose name is actually Art
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The member whose name is actually Art
Joined: Jan 2003
Posts: 7,538
Albany, NY
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Art, Yes I've kept He H pipe. Drone used to be real bad between 1700-2100 rpm. If I get some minor drone now it is around 1350-1400.
Do you think dropping the H improves that more? No. Adding the H pipe made my exhaust note quieter. How shall I say it?... The H allows exhaust shock waves from the firings of each cylinder bank to partially equalize before they hit the mufflers. My FlowMasters are louder than I want, but I prefer the "style" of sound that comes from going without the H pipe. So I'll compromise by going with quieter mufflers and delete the H. Best, - Art
65 Satellite hardtop 361/4bbl console 727 2.76 67 Satellite convert 383/2bbl column 727 3.23 67 Lancia Fulvia Sport 1.3 Zagato. Alloy body, 1.3L V4 DOHC 4-spd 67 Lancia Fulvia Rallye 1.3. Alloy panel, 1.3L V4 DOHC 4-spd 71 Alfa Romeo GT Junior 1300 Zagato, 1.3L 4cyl DOHC hemi 5-spd 82 Alfa Romeo GTV6 2.5L SOHC hemi V6 5-spd transaxle 75 Maserati Bora US spec 4.9L DOHC hemi V8 5-spd ZF 77 Maserati Khamsin Euro spec 4.9L DOHC hemi V8 5-spd ZF 07 Aston Martin DB9 6.0L DOHC V12 6spd transaxle
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Re: Muffler drone, Please recommend for ones that dont!
[Re: BSB67]
#2393559
10/26/17 10:41 PM
10/26/17 10:41 PM
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Joined: Nov 2003
Posts: 36,040 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
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just me I'd add the glasspacks & see what you gain, it'd be the easiest/cheapest.
live every 24 hour block of time like it's your last day on earth
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Re: Muffler drone, Please recommend for ones that dont!
[Re: 4mulaS]
#2393576
10/26/17 11:04 PM
10/26/17 11:04 PM
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Joined: Apr 2011
Posts: 315 Ontario, Canada
RealWing
enthusiast
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enthusiast
Joined: Apr 2011
Posts: 315
Ontario, Canada
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I had a drone on my 6.1 Hemi '69 Cuda with full TTI H Pipe exhaust and Dynomax Super Turbo mufflers. Plus the exhaust was quite loud when cruising. I installed a set of Flowmaster Resonators 15150S. Drone completely gone and exhaust much quieter. Very happy. These resonators are a straight through 2.5" design with a closed tube alongside. Photos in this FABO thread http://www.forabodiesonly.com/mopar/threads/srt8cuda-build.218445/page-27 Jim
1970 Superbird 440-6bbl, auto 1969 Barracuda 340-4bbl, FB Formula S auto 1969 Barracuda 6.1 L Hemi, 5 speed, Convertible 2022 Can Am Spyder RTL
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