Page 3 of 3 < 1 2 3
Topic Options
#2301510 - 05/08/17 11:00 PM Re: Muffler drone, Please recommend for ones that dont! [Re: Criterion]
Evil Spirit Offline
master

Registered: 01/02/05
Posts: 3653
Loc: Newport, Mi
Originally Posted By Criterion


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.........

Top
#2301562 - 05/09/17 12:41 AM Re: Muffler drone, Please recommend for ones that dont! [Re: 451Mopar]
Sunroofcuda Offline
master

Registered: 01/20/03
Posts: 6055
Loc: Highland, MI.
Originally Posted By 451Mopar
Originally Posted By Sunroofcuda
Originally Posted By 451Mopar
Originally Posted By 451Mopar
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.
_________________________
“Bear in mind that brains and learning, like muscle and physical skill, are articles of commerce. They are bought and sold. You can hire them by the year or by the hour. The only thing in the world not for sale is character.” (Antonin Scalia)

Top
#2301769 - 05/09/17 12:48 PM Re: Muffler drone, Please recommend for ones that dont! [Re: Sunroofcuda]
dogdays Offline
I Live Here

Registered: 01/20/03
Posts: 15814
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.

Top
#2301804 - 05/09/17 01:47 PM Re: Muffler drone, Please recommend for ones that dont! [Re: 4mulaS]
70Duster Offline
pro stock

Registered: 01/20/03
Posts: 1374
Loc: PA
Dynomax Ultra-Flows and the only thing better than the Super Turbos to eliminate drone.

Top
#2383281 - 10/07/17 12:42 AM Re: Muffler drone, Please recommend for ones that dont! [Re: 4mulaS]
4mulaS Offline
super stock

Registered: 01/18/06
Posts: 799
Loc: Alberta
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

Top
#2383358 - 10/07/17 10:18 AM Re: Muffler drone, Please recommend for ones that dont! [Re: 4mulaS]
bonefish Offline
master

Registered: 11/03/04
Posts: 6927
Loc: s.w.fl
if a set of mufflers will keep my wife out of MY! car i,m in for a set. up

Top
#2383410 - 10/07/17 11:44 AM Re: Muffler drone, Please recommend for ones that dont! [Re: bonefish]
RapidRobert Offline
Circle Track

Registered: 11/20/03
Posts: 32710
Loc: Lincoln Nebraska
Sounds like everyone is happy/knows what to do
_________________________
live every 24 hour block of time like it's your last day on earth

Top
#2385776 - 10/11/17 03:56 PM Re: Muffler drone, Please recommend for ones that dont! [Re: 4mulaS]
67SATisfaction Offline
master

Registered: 01/21/03
Posts: 6882
Loc: Albany, NY
Originally Posted By 4mulaS
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
_________________________
1965 Satellite hardtop 361/2bbl, auto, pegleg 2.76
1967 Satellite convert 383/4bbl, auto, pegleg 3.23
1975 Maserati Bora, 4.9L DOHC hemi V8, 5-spd ZF
1982 Alfa Romeo GTV6, 2.5L SOHC hemi V6, 5-spd transaxle
1994 Alfa Romeo 164LS, 3.0L SOHC 24v hemi V6, 4spd auto ZF
2007 Aston Martin DB9, 6.0L DOHC V12, 6spd full manual transaxle

Top
#2391971 - 10/23/17 04:51 PM Re: Muffler drone, Please recommend for ones that dont! [Re: 67SATisfaction]
4mulaS Offline
super stock

Registered: 01/18/06
Posts: 799
Loc: Alberta
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?


Edited by 4mulaS (10/23/17 04:51 PM)
_________________________
66Scar

Top
#2392576 - 10/24/17 07:54 PM Re: Muffler drone, Please recommend for ones that dont! [Re: 4mulaS]
astjp2 Offline
master

Registered: 01/18/11
Posts: 3981
Loc: Utah and Alaska
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!

Top
#2393151 - 10/25/17 09:42 PM Re: Muffler drone, Please recommend for ones that dont! [Re: 4mulaS]
67SATisfaction Offline
master

Registered: 01/21/03
Posts: 6882
Loc: Albany, NY
Originally Posted By 4mulaS
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
_________________________
1965 Satellite hardtop 361/2bbl, auto, pegleg 2.76
1967 Satellite convert 383/4bbl, auto, pegleg 3.23
1975 Maserati Bora, 4.9L DOHC hemi V8, 5-spd ZF
1982 Alfa Romeo GTV6, 2.5L SOHC hemi V6, 5-spd transaxle
1994 Alfa Romeo 164LS, 3.0L SOHC 24v hemi V6, 4spd auto ZF
2007 Aston Martin DB9, 6.0L DOHC V12, 6spd full manual transaxle

Top
#2393213 - 10/25/17 11:55 PM Re: Muffler drone, Please recommend for ones that dont! [Re: 4mulaS]
Dave Hall Offline
super stock

Registered: 01/21/08
Posts: 1194
Loc: Cotati, CA
I have a basically stock 400 in an A-body and full to the rear bumper 3" TTI headers and exhaust with an "H". This car does not drone at all now. When it was installed initially I hadn't used the headers yet but the same 3" exhaust behind manifolds and an RV type cam was terrible drone. I asked TTI about it and wondered if I got the quietest muffler they had? They said that I was sold the quietest muffler they had. It is either Magnaflow or Dynomax. I told them what I planned to do when I got around to pulling the motor and they said wait until you put that big cam in it and those headers and all that will go away. It has. I think this has more to do with a performance type exhaust behind a low performance camshaft.

Top
#2393473 - 10/26/17 04:25 PM Re: Muffler drone, Please recommend for ones that dont! [Re: R/T1968R/T]
dogdays Offline
I Live Here

Registered: 01/20/03
Posts: 15814
The Dynomax catalog says this:
100% Aluminized Inside and Out. Heavy Gauge, Hand Welded Case. Straight Through Design for Maximum Flow. Aggressive Sound Level with a True Performance Tone and Minimal Resonation. High Temperature Roving Fiberglass. Reversible for Versatile Installation. Lifetime Warranty. Made in USA

It's no wonder they are loud.

The sound of exhaust is the individual pulses of the gas from the exhaust stroke. There are two ways to reduce the amplitude of the pulses. You can dampen it which reduces the strength of the pulses, which nearly every muffler does, or you can use the pulses to cancel each other out. This works the same way that noise canceling headphones work. Flowmasters use this principle.

There may be some phase canceling in the dampening mufflers but I'm not familiar with it.

No muffler works by adding backpressure, but it happens anyway. A muffler designer usually looks for the greatest reduction in sound level with the smallest amount of backpressure.

To the OP: I suggest making the exhaust system quieter by using an H-pipe, then adding the glasspack resonaters under the trunk. The exhaust has lost temperature by then and so the volume of exhaust and its velocity are reduced.

R. I'm waiting for a former Walker employee to set this post straight.


































































Reviews

Top
#2393515 - 10/26/17 06:42 PM Re: Muffler drone, Please recommend for ones that dont! [Re: Dave Hall]
BSB67 Offline
master

Registered: 02/19/05
Posts: 3368
Loc: Prospect, PA
Originally Posted By Dave Hall
....and they said wait until you put that big cam in it and those headers and all that will go away. It has. I think this has more to do with a performance type exhaust behind a low performance camshaft.


I too think it is from the manifolds and cam design, but not necessarily (or only from) a low performance cam. twocents
_________________________
500" NA, Eddy head, pump gas, exhaust manifold with 2 1/2 exhaust with tailpipes 4150 lbs with driver, 3.23 gear, stock converter 11.68 @ 120.2 mph

Top
#2393559 - 10/26/17 08:41 PM Re: Muffler drone, Please recommend for ones that dont! [Re: BSB67]
RapidRobert Offline
Circle Track

Registered: 11/20/03
Posts: 32710
Loc: Lincoln Nebraska
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

Top
#2393576 - 10/26/17 09:04 PM Re: Muffler drone, Please recommend for ones that dont! [Re: 4mulaS]
RealWing Offline
member

Registered: 04/24/11
Posts: 190
Loc: Ontario, Canada
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
2015 BMW K1600 GTL

Top
#2401772 - 11/11/17 05:40 AM Re: Muffler drone, Please recommend for ones that dont! [Re: RealWing]
sogtx Offline
master

Registered: 07/25/03
Posts: 4716
Loc: upstate western ny
Not for nothing , but the state of tune of your car
WILL create or eliminate drone on some setups

What a-f do you cruise at ?

Top
#2401778 - 11/11/17 06:15 AM Re: Muffler drone, Please recommend for ones that dont! [Re: 4mulaS]
360view Offline
master

Registered: 01/18/06
Posts: 4139
Loc: USA
Air to fuel ratio changes will change
exhaust gas temperature which changes
the speed of sound in the exhaust gas
which will change the rpm at which the drone resonance will be loudest.

I had not thought of it before but pumping in cooler outside air into a hot exhaust system would change the rpm at which drone occurs. If a 12V air compressor was used it could be switched on/off to observe the effect. In a low backpressure exhaust system a forward facing "draft tube" might add enough air to shift the drone rpm.

We have discussed T junction stubs to cancel drone here on moparts.
The Flowmaster resonators in the post above have a stub of pipe inside the resonator case. It looks neater but you cannot "fine tune" the effect by lengthening or shortening the stub length.

Top
Page 3 of 3 < 1 2 3

Advertisement
Sponsored Link
Forum Stats
24,969 Registered Members
32 Forums
185,452 Topics
2,149,423 Posts

Most users ever online: 882 @ 03/05/17 10:15 PM
Moparts Newest Topics
70 Cuda Grille and Grille Molding Options
by rss
Today at 02:19 AM
Garage door guys. Help leveling door.
by MoparPosterChild
Today at 12:47 AM
Well, I did it. '17 Challenger.
by 68SportFury
Yesterday at 10:23 PM
Similarity between new Durango taillights and 70 GTX grill
by Airgrabber
Yesterday at 10:11 PM