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nastang87xx

All you need to know about exhaust "drone"

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Drone is that loud humming noise after you've installed your cool shiny new exhaust system around 1800 - 2200RPM depending on your final drive ratio.  It's very annoying for most and will drive your girlfriend (or boyfriend) right out of the car.  So what is it?  What causes it?  What can I do about it?

 

 

What is it?

Drone is the word to describe a resonance phenomenon that offends nearly every type of material on the planet as a specific frequency range.

 

 

What causes it?

This sound frequency range is typically between 133 - 138hz for cars.  This frequency sends the energy through the metal frame, body work, and everything in between (even seats in some cases) and shakes the molecules creating an awful humming sound.

 

 

What can I do about it?

Not much.  You can't really block this frequency range because it is a natural resonance frequency.  It will rattle EVERYTHING (even materials like wood and some softer materials as well). Dynomat in your trunk won't work.  Dynomat on your floorboards or on the unibody underneath your seats won't work.  This range of 133 - 138hz is incredibly difficult to manage.  The best way to address drone is with muffler design or resonators.  The factory mufflers are specifically designed to not only block but also CANCEL these frequencies.  Some aftermarket designs such as Borla's and Corsa's offerings do the same job.  Borla's design cancels out some of these frequencies as well as ensures that the sound energy is going out the tailpipes.  Corsa's designs have an internal chamber that is of the correct length to cancel this frequency out using the laws of wave reflection.

 

Designs like the Magnaflow Competition Catback that uses a 5"x14" resonator to attenuate the engine sound drone like a mad cow.  Flowmaster American Thunder mufflers drone like crazy because they were designed to produce a specific sound that was focused on the outside of the car.  There's nothing wrong with this, it's just what the manufacturers decided to produce.  If you have an exhaust system with one of these such designs and don't want to change your entire system, then a set of straigh through race mufflers such as Dynomax Race Bullets or Pypes M80 mufflers will give you some relief but may not completely eliminate the drone depending on your overall setup.

 

 

What else to take away from this?

Remember, exhaust systems are exactly that: systems.  They sound, flow, and benefit your engine setup the best when thought of as a whole and variables are taken into consideration under every circumstance.

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We should start a list of people's personal experience with their exhaust setup, and add a subjective scale on how bad their drone is.

 

My first setup: stock headers and cats, Magnaflow 3" after-cat x-pipe, Magnaflow 3" Street catback.

 

Drone(1-10), 3. Worst at 1,900rpm.

 

Current setup, 1 7/8" longtube headers, custom catted h-pipe, stock overaxle pipes with Pypes M80 mid mufflers, Borla S-type axlebacks.

 

Drone, 0.5<-- only because of the sheer volume the system can cause parts of the car to vibrate.

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2012 GT

 

1. Stock headers and H-pipe, Pypes Catback.

 

Drone, 5.  Worst at 2k

 

2. BBK Longtubes, O/R Xpipe, Pypes Catback

 

Drone, 9.  Worst at 2k, seriously unbearable.  Had to drive up and buy Grimace's catback  :P

 

3. BBK LTH, O/R X, Magnaflow Street Catback

 

Drone, 0.5.  No real drone to speak of, very nice.

 

2013 Boss

 

4. '13 GT500 axle backs

 

Drone, 0

 

5. BBK LTH, O/R X, '13 GT500 Axle backs

 

Drone, 0. awesome setup.  Raspy though from the X

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2011 GT, Manual, 3.73's, Airaid intake

Setup 1
Headers: OEM
Converter Sections: OEM
Mid Pipe: OEM
Catback: Magnaflow Competition Catback

Drone Intensity: 10/10


Setup 2
Headers: OEM
Converter Sections: OEM
Mid Pipe: Ford Racing X Pipe/BBK X Pipe/Magnaflow TruX Cut and Clamp
Catback: Magnaflow Competition Catback

Drone Intensity: 8/10


Setup 3
Headers: Kooks 1 7/8"
Converter Sections: Kooks High Flow Catted X Pipe
Mid Pipe: Kooks High Flow Catted X Pipe
Catback: Magnaflow Competition Catback

Drone Intensity: 6/10

 

 

Setup 4 *Updated July 2013*

Headers: Kooks 1 7/8"

Converter Sections: Kooks High Flow Catted X Pipe

Mid Pipe: Kooks High Flow Catted X Pipe

Catback: Lethal Performance Over Axle Gen 2 Pipes, Kooks Axle Back

 

Drone Intensity: 2/10

 

 

Setup 5 *Updated August 2013*

Headers: Kooks 1 7/8"

Converter Sections: Kooks High Flow Catted X Pipe

Mid Pipe: Kooks High Flow Catted X Pipe

Catback: Stainless Works Retro Chambered Catback

 

Drone Intensity: 4/10

 

 

Setup 6 *Updated January 2014*
Headers: Kooks 1 7/8"
Converter Sections: Kooks High Flow Catted X Pipe
Mid Pipe: Kooks High Flow Catted X Pipe
Catback: Lethal Performance Over Axle Gen 2 Pipes, Borla ATAK Axle Back

Drone Intensity: 0/10

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Great write-up! I've been looking for drone information and couldn't find anything.

And don't let anyone tell you otherwise. ;)   But seriously, when choosing exhaust systems and parts, choose wisely and with the thought in mind that you might change something or how a change might affect your overall enjoyment of the car.

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And don't let anyone tell you otherwise. ;)   But seriously, when choosing exhaust systems and parts, choose wisely and with the thought in mind that you might change something or how a change might affect your overall enjoyment of the car.

 

I personally do not mind drone, but the longest trip I had in my 05 was about 2-1/2 hours so I can't be taken into consideration. Worst case I'll just either put the windows down or turn the sound system up! 

 

I was thinking  of going with these http://www.americanmuscle.com/flowmaster-outlaw-axleback-1112gt.html because of the straight trhough design and they probably are lighter than stock also.

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Outlaws drone like a PIG.  Probably the worst I've heard in a long list of systems.  But if it doesn't bother you, more power to you.  I wish I had that tolerance.  My drone isn't terrible anymore but you can definitely tell that the car drones.  It usually hits about 78'ish dB's inside the car if I slightly lug the engine while cruising at 1900RPM.  When I had just the catback, it would hit about 81dB inside the car.

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2012 GT

 

1. BBK Shorties SS headers,  Magnaflow 3" True X Catless, removed factory resonators and Flowmaster Hushpower...

 

Drone, ?.  Worst at ...?

 

To be honest, with Breaking Benjamin at 50% volume when driving to the track, no drone at all, mine is not a DD.

On the track I'm wearing a helmet so...

I'm gonna pay some more attention because if it has not bothered me...

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Outlaws drone like a PIG.  Probably the worst I've heard in a long list of systems.  But if it doesn't bother you, more power to you.  I wish I had that tolerance.  My drone isn't terrible anymore but you can definitely tell that the car drones.  It usually hits about 78'ish dB's inside the car if I slightly lug the engine while cruising at 1900RPM.  When I had just the catback, it would hit about 81dB inside the car.

I'd love to find out how loud its inside, do you know if there is an app for a Galaxy SIII? I mean how can I measure it??

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I'd love to find out how loud its inside, do you know if there is an app for a Galaxy SIII? I mean how can I measure it??

 

I have the one named "sound meter" that I use in my work for when I want a "unconfirmed" db reading of the pumps, its worked out for this ok so I guess for the car it should work fine.

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Outlaws drone like a PIG.  Probably the worst I've heard in a long list of systems.  But if it doesn't bother you, more power to you.  I wish I had that tolerance.  My drone isn't terrible anymore but you can definitely tell that the car drones.  It usually hits about 78'ish dB's inside the car if I slightly lug the engine while cruising at 1900RPM.  When I had just the catback, it would hit about 81dB inside the car.

 

intereseting...I'll try to see if I can get a face-to-face look soon.

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I didn't take a measurement of the Outlaws but it was a bone stock car except for Outlaw axle backs.  It seemed like it droned louder than my Magnaflow Comps.  They were also louder than my Comps, too.  And that was even with the factory resonators, granted they don't do much.

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I have the Mac axle backs on my 2014 5.0 and they drone like

A

Mother fu**er!!! 2k is the worst. I guess it's because they're a chambered muffler design. They're one of the best sounding exhausts I've heard though to be

Honest.

  • Like 2

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Awesome thread! I only have Borla S-Types right now and on a 1-10 scale I would say they're about a 2 but take that with a grain of salt as I've never been in something that would be considered to have a lot of drone.

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I have the Mac axle backs on my 2014 5.0 and they drone like

A

Mother fu**er!!! 2k is the worst. I guess it's because they're a chambered muffler design. They're one of the best sounding exhausts I've heard though to be

Honest.

 

Welcome to the forum!!

 

I had SW LT's with matching O/R X-pipe and MAC axlebacks on my old '11 Coyote car.  There was some drone like you mentioned by the exhaust note on the car was excellent!!

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I have the Mac axle backs on my 2014 5.0 and they drone like

A

Mother fu**er!!! 2k is the worst. I guess it's because they're a chambered muffler design. They're one of the best sounding exhausts I've heard though to be

Honest.

 

Yes, I've heard that they drone TERRIBLY!  Don't know by experience though.  Welcome to the forum!

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I have the Mac axle backs on my 2014 5.0 and they drone like

A

Mother fu**er!!! 2k is the worst. I guess it's because they're a chambered muffler design. They're one of the best sounding exhausts I've heard though to be

Honest.

 

 

Welcome to the forums. Feel free to introduce yourself in the members introduction thread.

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