Exhaust Drone Cure
05-03-2013, 02:44 PM
#1
Member
Thread Starter
Exhaust Drone Cure
Cure or bandaid, I'm not sure.
I have a 2012 5.0L and replaced the stock muffler with a Magnaflow 3" SISO, along with replacing the pipe from the muffler to the factory ball/socket flange with a 3" pipe (retained the factory tailpipe).
No surprise, it had a resonance that peaked around 1600 rpm when cold and shifted up to around 1900 rpm when up to temperature. Right in the cruise RPM. For a daily driver, that howl sucks (and I have a 69 mustang with the smallest Borla XR-1 Sportsman with dual 3" all the way to the back...).
So I made up a 1/4 wave resonator and installed it ahead of the muffler. I simply picked up a piece of 2.5" diameter, 5" radius, 409 stainless U-Bend along with a Pypes butt type clamp. I cut a piece of stainless to cap the end of the extension. It has a very slight rise to ensure water can drain if needed. It's above the main tube, so it's really difficult to see (either from the side, back or from the wheelwell.
The initial total length is 30". I was calculating needed something in the 24" range, but wanted to start as long as possible using the material I had, then trim it down and retest if needed. At the initial length the noticeable drone is 100% gone. So I haven't trimmed the extension any more. I also don't notice any power loss. If i drag the truck again, I may just loosen up and remove the clamp and capped extension, for a somewhat of a dump.
I have a 2012 5.0L and replaced the stock muffler with a Magnaflow 3" SISO, along with replacing the pipe from the muffler to the factory ball/socket flange with a 3" pipe (retained the factory tailpipe).
No surprise, it had a resonance that peaked around 1600 rpm when cold and shifted up to around 1900 rpm when up to temperature. Right in the cruise RPM. For a daily driver, that howl sucks (and I have a 69 mustang with the smallest Borla XR-1 Sportsman with dual 3" all the way to the back...).
So I made up a 1/4 wave resonator and installed it ahead of the muffler. I simply picked up a piece of 2.5" diameter, 5" radius, 409 stainless U-Bend along with a Pypes butt type clamp. I cut a piece of stainless to cap the end of the extension. It has a very slight rise to ensure water can drain if needed. It's above the main tube, so it's really difficult to see (either from the side, back or from the wheelwell.
The initial total length is 30". I was calculating needed something in the 24" range, but wanted to start as long as possible using the material I had, then trim it down and retest if needed. At the initial length the noticeable drone is 100% gone. So I haven't trimmed the extension any more. I also don't notice any power loss. If i drag the truck again, I may just loosen up and remove the clamp and capped extension, for a somewhat of a dump.
Last edited by BuckeyeDemon; 05-03-2013 at 05:41 PM. Reason: added one more photo
The following 4 users liked this post by BuckeyeDemon:
05-03-2013, 02:49 PM
#2
Senior Member
Interesting .....
.
.
05-03-2013, 04:49 PM
#4
Member
Thread Starter
I'm guessing you haven't heard of a Helmholtz resonator, or 1/4 wave resonator?
http://en.wikipedia.org/wiki/Helmholtz_resonance
It's the same technique Ford uses on the intake manifold tube (2012 F150 5.0) to reduce the noise associated with the intake resonance.
Or the same technique Corsa tries to employ inside their mufflers:
Corsa Technology
It's also the same technique we use at work with our X-band (8GHz) transmitters (weather/data satellite) in the RF circuits to match impedances of the transmission lines and amplifiers (instead of a velocity of propagation based on the speed of sound, its velocity of propagation is based on the speed of light).
05-03-2013, 05:32 PM
#5
Senior Member
Great job Buckeye Demon,
And great response to someone that obviously speaks before he thinks, you know the guy that blows his horn at you because he cut you off in your lane
Anyway Solo also uses this and makes theirs adjustable. I think Solo calls it a J-hook. I remember a post that included a formula to figure the length. i think it was on another forum.
And great response to someone that obviously speaks before he thinks, you know the guy that blows his horn at you because he cut you off in your lane
Anyway Solo also uses this and makes theirs adjustable. I think Solo calls it a J-hook. I remember a post that included a formula to figure the length. i think it was on another forum.
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Russellb (09-27-2016)
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05-03-2013, 06:21 PM
#8
Senior Member
Wow that looks nice. Did you do the welds yourself? I've done some welding and I can't imagine doing it on a curved surface. I can't imagine how much a shop will charge to fab one of these up.
05-03-2013, 06:30 PM
#9
Very nice response.
I'm guessing you haven't heard of a Helmholtz resonator, or 1/4 wave resonator?
Helmholtz Resonance
It's the same technique Ford uses on the intake manifold tube (2012 F150 5.0) to reduce the noise associated with the intake resonance.
Or the same technique Corsa tries to employ inside their mufflers:
Corsa Technology
It's also the same technique we use at work with our X-band (8GHz) transmitters (weather/data satellite) in the RF circuits to match impedances of the transmission lines and amplifiers (instead of a velocity of propagation based on the speed of sound, its velocity of propagation is based on the speed of light).
I'm guessing you haven't heard of a Helmholtz resonator, or 1/4 wave resonator?
Helmholtz Resonance
It's the same technique Ford uses on the intake manifold tube (2012 F150 5.0) to reduce the noise associated with the intake resonance.
Or the same technique Corsa tries to employ inside their mufflers:
Corsa Technology
It's also the same technique we use at work with our X-band (8GHz) transmitters (weather/data satellite) in the RF circuits to match impedances of the transmission lines and amplifiers (instead of a velocity of propagation based on the speed of sound, its velocity of propagation is based on the speed of light).