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Discussion Starter #1
So a buddy of mine gave me a set of Flowmaster super 44s to make my '82 sound a bit rowdier than it currently does and while I'm certainly no stranger to loud cars, interior drone drives me nuts. I was thinking about welding in a set of probably 12" resonators upstream of the mufflers at the same time. Does anyone have any experience trying this? I know the super 44s inherently come with a good bit of drone and while I had pretty good success doing this on a cammed GTO, I know the Elcos are an entirely different beast.
 

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I must have spent at least a thousand bucks getting the drone out of my 86 ! I would have sold it if I had to listen to droning. I have two stock mufflers and resonator tips to get rid of it, finally. You're going to get all kinds of feedback on this subject ,so beware.
 

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having a properly sized exhaust is very important, to large of diameter tubing can cause drone.


a well insulated interior can help reduce drone a lot.


I'm running the Super 44s, granted my exhaust sys is 3" because it needs to be, double sound matting on the floors, and haven't noticed any drone.
 

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My entire interior ,everything, is covered in Dynamat and it didn't touch the drone from the first two exhaust setups. Most people use way too big exhaust and you're right, it causes problems.
 

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Discussion Starter #5
having a properly sized exhaust is very important, to large of diameter tubing can cause drone.


a well insulated interior can help reduce drone a lot.


I'm running the Super 44s, granted my exhaust sys is 3" because it needs to be, double sound matting on the floors, and haven't noticed any drone.
I laid down dynamat pretty much everywhere in the interior a while back but I still don't expect it to do much. I'm only running 2.5" dual exhaust on mine with a set of long tubes at the moment but I may throw on a pair of resonators to be on the safe side
 

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Couple of suggested areas for soundproofing that many forget...roof and side panels of body and doors. Also, where does your exhaust exit? I was at SEMA and told by Flowmaster staff that there should be no drone issues with 40s or 44s provided the exhaust exits behind either the rear wheels or farther back.
 

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A friend suggested Magnaflow mufflers while I was doing my swap. He said they still have a Flowmaster sound but you can have a conversation on the highway! He was right, my Magnaflows with 2 1/4 pipes do make some noise but to me is just right between stock and too loud.

Joe
 

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Yep,I agree on the Dynamat . My complete interior, roof,kick panel areas, outer, inner door skins, floor,burglars boxes,EVERYHTING ,and the drone still came thru !!
 

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Has anybody tried putting motorcycle baffles in the tailpipes to quiet the drone down? I have Flowmaster 40's with 2 1/4" pipes thru out with drone thru the gears until OD takes over. The pipes exit outside the body in stock position with the slank on the tip facing down. I was planning on insulating the interior this coming winter for a project to hopefully get rid of the drone. Thanks for your input Wayne and other members.
 

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Hi, 79 elky, 350 with 2 1/4” true duals, H pipe, bumper exit. I am a pro auto restorer with 40 years of auto body experience, so not only did I Dynamat and dynapad pretty much EVERYthing, I took a few additional steps and used 3m 2-part structural and acoustical foams in hollow areas such as the A and C pillars, floor braces, under the back windows, even inside the door beams like many new cars. With the engine off, it’s quieter than my Lexus, Running, with a pair of 14” Dynomax turbos, was headache inducing drone. I then went to 18” Maganaflows upon the advice of several exhaust guys, and it’s only a marginal improvement, still not fun to listen to very long. I started out with 18” Walker super turbos, a part number now listed under their “Quiet series”. Flow specs were much poorer, hence no exhaust guys would recommend them vs “performance” brands, however drone was never an issue with them. My research indicates, that “noise cancelling” occurs when a second muffler or effective resonator is introduced in the system that works on additional frequency attenuation. Am I correct to assume that most of us with drone don’t have a cat in system?
 

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told by Flowmaster staff that there should be no drone issues with 40s or 44s provided the exhaust exits behind either the rear wheels or farther back.
This is patently FALSE! My flowmaster system (the entire thing designed by flowmaster) exited out the back of the car and had a HUGE amount of resonance. I like the sound of a flowmaster 40 / 44 but I cannot ignore to the resonance like I could when I was younger. Changed my mufflers to Hooker Max Flow.
 

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Make sure all connections are tight and leak free.. I only use Walker stainless clamps.. Under the clamp I use one zip screw to keep the pipe from twisting. I run the screw in first then back it out, cut off most of it and run it back in so it doesn't whistle. Then I put 3M high temperature tape around the joint and put the clamp over it and crank it down. Then I crank the clamps down again after a driving it a few hundred miles..

 
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