reducing exhaust drone

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22dog22

22dog22

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has anyone tried one of those exhaust silencers that you put into the exhaust pipes ? some are made by Vibrant looking for feed back to try to tone down the drone in my car with out cutting up the new exhaust system
 
have tti long tube ceramic headers, have 2.5 Pypes stainless steel pipe with x pipe, with 2 Dynomax 17629 2.5 in and out mufflers ,pipes go all the way to rear bumper with chrome tips. i see that some people put a exhaust silencer into the tailpipe end to help reduce the drone .
 
Have heard going straight out from under the bumper instead of turn down tips helps eliminate the drone. So the sound waves are not bouncing back up off the highway back into the car.
 
i do not have turn downs, have been reading about adding a j-pipe that is capped at the end hooked into the exhaust pie has anyone done that ? is there a bolt on kit ?
 
22dog22 said:
with 2 Dynomax 17629 2.5 in and out mufflers
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are these 3-pass muffs?
Is the exhaust suspended on isolation hangers.?
Drone, on a full-length system, is almost always caused by the mufflers.
>Unless it happens at about 55 mph, which is the speed at which the rotating tires like to excite the body's natural frequency of vibration. or
>Unless you are cruising with windows down, which will also excite it. or
>Unless your cruise rpm is extremely low.

I have never heard of "exhaust silencers" that you stick into the tailpipes.
Great idea tho; I made my own back in 1976. I rolled up some corrugated cardboard and stuffed them up the pipes then pinned them into place with nails. To get them out (they were stuffed way up there so the cops couldn't see them), I pulled the nails and rapped the throttle a couple of times until they blew outta there, lol.
Now I have TTI turndowns.No drone.
 
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AJ/FormS said:
are these 3-pass muffs?
Is the exhaust suspended on isolation hangers.?
I have never heard of "exhaust silencers"
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If he is referring to the "J" shaped pipes as exhaust silencers, he's talking about helmholz resonators, and they definitely work.
There are no kits, because they have to be tuned to the resonant frequency you are trying to cancel. There is math, and fabrication involved.
 
Have you thought about putting resonators at the end of your exhaust system just like the factory mopar cars were originally made with.

Gives them that unique mopar exhaust sound. Have them at the very end of my Truck's dual exhaust system.

Screenshot_20220609-203837_Gallery.jpg

Rear Resonators with dual mufflers just in front of the rear axle .
 
On my Demon 340/4speed with 3:23 suregrip had that drone at cruising speed.
TTI exhaust and dyno flow mufflers. I changed the rear gears to 3.91
And the drone is gone…. So is my fuel. Lol!
 
On a full length system you have two variables that stand out, the mufflers and the diameter of the system.

Adding a resonator between the mufflers and the bumper will help and will not hinder performance aside from the added weight.
 
I am leaning towards the resonator way, but the price for the Flowmaster 15150s is $160.00 each, and needing 2 is over $300.00, found Vibrant 1141 which is about the same size and spec as the Flowmaster units, and just also found that Summit has there own # sum 639436 for only $70.00 each, has anyone used any of these to give feed back on ??
 
Check out Jones exhaust at summit. I don't think summits profit margin is real good so they don't mention them.
I would just get a short glasspack of theirs, to use as a resonator. Just get the same size as your pipe.
 
roccodart440 said:
On a full length system you have two variables that stand out, the mufflers and the diameter of the system.

Adding a resonator between the mufflers and the bumper will help and will not hinder performance aside from the added weight.
Click to expand...
X pipes do cause a major drone at a steady throttle. Hear it on mustangs all the time. X pipes are dual purpose. exhaust flow interference crossover and driveshaft loop all in one LOL.
 
I have the same DynoMax turbos and they drone badly. Worse than anything I've ever used and I run 300 Cell Cats before them. Add resonators in the form of off the shelf like the Vibrant or Helmholz chambers. It all depends on how much room you have.

I'm ditching my Dynomax Turbos for longer case Jones Max Flow and small but long resonators just after the cats.
 
22dog22 said:
I am leaning towards the resonator way, but the price for the Flowmaster 15150s is $160.00 each, and needing 2 is over $300.00, found Vibrant 1141 which is about the same size and spec as the Flowmaster units, and just also found that Summit has there own # sum 639436 for only $70.00 each, has anyone used any of these to give feed back on ??
Click to expand...
Summit has a Jones resonator, stainless, 10" case, 14 oal, 2 1/2 in/out, for under $50. JEX-JR25.
 
Ricks70Duster340 said:
I had delta flow 50's on my car and the drone was horrible. Changed to a different muffler to resolve.
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Interesting. I have never cared for the flow master sound, though most I know use the 40 or 44 series. Been looking for someone who has the 50 or 70 series to see what they sound like for consideration on a future build.
Besides that, I have a (not very) used 50 here (single in, dual out) that I got for a song (very cheap) from a member here that I was thinking about putting on my /6 pick up. Because it's 3"in/out that has been adapted down to 2-1/2, I am thinking it won't "muffle" much being as how it's that much bigger than the exhaust ahead of and behind what this muffler is.
I also know that an inline 6 had a sound all it's own which is kind of "droney" from the get go compared to a V8....
I have the Thrush welded (their copy of a flow master) on my otherwise stock 318 in my Fury (still rocking lean burn even, at this time, it's "that" stock!) And it's slightly louder than I'd like-- not obnoxiously so though-- there's no drone. It has true duals all the way from manifolds to the bumper. Tails exit straight out under the bumper, not turned down.
Though as I sit here hunting and pecking this on my phone, I can't remember whether they ran 2&1/4 or 2&1/2" pipe, it's been on there over 10 years.
Though when I had my Diplomat, I had headers and "muffler shop turbos" on that one also true duals run all the way out, and that one was definitely 2-1/2 tube/ that exhaust was obnoxiously loud.

Then (another 318) when I had my 83 D250 and put headers on that one and true duals again with "muffler shop issue" turbos that one was definitely hearable but was nice and mellow..... Don't know what the difference might have been there?
 
volaredon said:
Interesting. I have never cared for the flow master sound, though most I know use the 40 or 44 series. Been looking for someone who has the 50 or 70 series to see what they sound like for consideration on a future build.
Besides that, I have a (not very) used 50 here (single in, dual out) that I got for a song (very cheap) from a member here that I was thinking about putting on my /6 pick up. Because it's 3"in/out that has been adapted down to 2-1/2, I am thinking it won't "muffle" much being as how it's that much bigger than the exhaust ahead of and behind what this muffler is.
I also know that an inline 6 had a sound all it's own which is kind of "droney" from the get go compared to a V8....
I have the Thrush welded (their copy of a flow master) on my otherwise stock 318 in my Fury (still rocking lean burn even, at this time, it's "that" stock!) And it's slightly louder than I'd like-- not obnoxiously so though-- there's no drone. It has true duals all the way from manifolds to the bumper. Tails exit straight out under the bumper, not turned down.
Though as I sit here hunting and pecking this on my phone, I can't remember whether they ran 2&1/4 or 2&1/2" pipe, it's been on there over 10 years.
Though when I had my Diplomat, I had headers and "muffler shop turbos" on that one also true duals run all the way out, and that one was definitely 2-1/2 tube/ that exhaust was obnoxiously loud.

Then (another 318) when I had my 83 D250 and put headers on that one and true duals again with "muffler shop issue" turbos that one was definitely hearable but was nice and mellow..... Don't know what the difference might have been there?
Click to expand...
I have the Flowmaster big block series 50 53553,(not the delta flow) on my car, and I love the sound (I like the Flowmaster sound, generally). They are 3 1/2 in/out, tailpipes to the bumper with turndowns. No drone, but they are HUGE. I don't think you could get them under an a-body, they were a tight fit on my b-body. The loudness is moderate considering the size, and the engine in front. Though what might be fine for me, might be obnoxiously loud for you, or vice versa.
I certainly wouldn't use them again however. The were a high-priced $100 when I bought em, $225 ea. this morning.
I also have used 3 1/2 hooker aero's, liked them too, ran them with just turn downs. Went nines with a n/a small block thru them, they must not be a real bad muffler. No drone.
 
I don't know what the difference is between delta flow versions and non delta but I believe this one I have to be a delta version, would have to go look
 
volaredon said:
I don't know what the difference is between delta flow versions and non delta but I believe this one I have to be a delta version, would have to go look
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Every real Flowmaster I have seen has the part # etched into the rear face plate. Part# will tell you what it is.
 
Not saying this is the case but I wonder how many droning issues are caused by an impropper tune ? My car was really loud at cruise until I got the timing and jetting dialed in .
 
Flowmasters are misnamed, should be FlowLess. No place on a car.

Unfortunately, no easy fix for drone/resonance. H or X pipe might cause resonance on some cars, others it doesn't. It doesn't on my car.....

Every car is different & once the engine is no longer stock, you change how it behaves under load.

The fix is experimentation. Different mufflers, different hangars etc.
 
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