exhaust drone...mood? discouraged

[MADDOG]

So where did they install the resonator in the system?

 

[buddy guy]

Ahead of the muffler. No change in position to muffler

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[Musky Mike]

There are certain frequencies within your exhaust pulses that cause the drone effect. Factory chambered mufflers captures the frequencies in the chambers, this removes the frequency causing the drone from the exhaust pulse. A resonator (like the one you had installed) works a different way, it absorb the frequency through the perforated core and into fiberglass or stainless steel matting, thus removing it. For the J-pipe, as the frequencies travel down the tube, when they get to the end they reflect (reverse) and hit the incoming frequency canceling them out both out. All three of the drone canceling technologies have to be set-up (tuned) for the drone frequencies your are trying to eliminate. Without compromising exhaust flow or sound, the J-pipe is your best solution. Mufflex should have enough experience with Ram/Hemi to tell/sell you the right length J-pipe to eliminate your drone. Different length J-pipes cancel different frequencies, so it's important to have the right length. Most likely the resonator you had installed wasn't a perfect match to absorb the frequencies that are causing your drone.

 

[buddy guy]

There are certain frequencies within your exhaust pulses that cause the drone effect. Factory chambered mufflers captures the frequencies in the chambers, this removes the frequency causing the drone from the exhaust pulse. A resonator (like the one you had installed) works a different way, it absorb the frequency through the perforated core and into fiberglass or stainless steel matting, thus removing it. For the J-pipe, as the frequencies travel down the tube, when they get to the end they reflect (reverse) and hit the incoming frequency canceling them out both out. All three of the drone canceling technologies have to be set-up (tuned) for the drone frequencies your are trying to eliminate. Without compromising exhaust flow or sound, the J-pipe is your best solution. Mufflex should have enough experience with Ram/Hemi to tell/sell you the right length J-pipe to eliminate your drone. Different length J-pipes cancel different frequencies, so it's important to have the right length. Most likely the resonator you had installed wasn't a perfect match to absorb the frequencies that are causing your drone.

Thx for this. Yes the more I think about it the more I give the shop an A+ for ability to do the job but disappointed from a creative & problem solving standpoint. This is a shop with a great rep, the father himself has 40+ years of experience, everything from typical vehicles to custom exhausts so when he recommended this resonator I thought he would KNOW. Or maybe I'm pickier than his average customer. There is a thread on this forum about the Jpipe. The mufflex part number is there so I assume thats the guy to chase down if i go that route.

https://www.ramforum.com/threads/anyone-running-the-mufflex-j-pipe-dodjp.86530/page-3

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[Musky Mike]

This is a copy and paste, but here is the science behind it:

Exhaust drone is a problem I've been dealing with and most of the time people solve it by trying various mufflers, resonators, and sound deadening until they like the outcome. There is, however, and exact science to eliminating drone: calculate the drone wavelength and cancel it with a resonator tube. You can also use the sound frequency to buy the correct sound suppression material since the better ones have different material for different frequencies.

Here's the formula to get the tube length:

((343)/(RPM * 4 * (1/60))) / 4

Just replace RPM with the RPM where drone is at its worst.

E.g. ((343)/(2500 * 4 * (1/60))) / 4 = 0.5145 meters

For drone at 2500 RPM you need to weld a capped exhaust pipe 0.5145 meters in length before your muffler, as perpendicular to your existing pipe as possible (it should look like a T). It's as simple as that. Although it's often called a j tube, it's actually better if it's straight, as the more it bends the more sound bounces back before reaching the full length. The j shape comes from having to fit it in small spaces. If you can't weld, with this number you can tell any exhaust shop what to do.

Tip: if you just want the frequency for buying the correct sound suppression, use this part:

2500 * 4 * (1/60) = 166.67 Hz (replace 2500 with your drone RPM)

For those who are curious, here's the formula breakdown:

• 343m/s is the speed of sound
  
  
• 4 is the number of pulses per rev the engine makes (a V6 would be 6, but some engines fire two at once, so a V8 would still be 4).
  
  
• 1/60 to convert from minutes to seconds.
  
  
• /4 divides the wavelength by 4 to get the length of tube that will cancel out the frequency.
  

 

[U&A]

I have ZERO drone since i went SOLO Delete Pipe


Sent while firmly grasping my redline lubed RAM [emoji231]

 

[shadowhawk]

I saw the MF drone eliminator but at their price I was willing to just deal with it. That said, we have a 3000+ mile trip planned next month and I may have to do something ahead of that trip. A j-pipe is a good option if I can get a local shop to replicate the overpriced MF version.

 

[pacofortacos]

Are the original resonators still in place? Or just the one before the muffler - which really isn't where they work the best.

 

[buddy guy]

I reached out to my installshop about the J pipe. They are willing to "put it in & see how it goes", if I get the part, but I get the feeling they wouldn't give me anything for the resonator I bought. Not really surprised. I think lesson learned & next time I'll get a catback and do it myself? (I can't weld but figure if I install & clamp. And ultimately get a shop to weld it if need be? Am I making sense?

In regards to my current situation...After upgrading my coils (love the 1223vts!) I took a blast on the highway & decided while its not perfect, it is improved. It never was teeth chattering, I just like things to be perfect. I 95% drive in the city where I don't notice the drone. The other thing I noticed on the 2nd drive is before, the drone was pretty much the same lvl from 1500 to 2000 rpm. I notice 1500 to 1700 is more subdued than 1700 to 2000. And at 100 to 105km per hour I think it is, I'm operating in that 1500 to 1700 with my 6 speed...and we have very few 110km per hour highways in alberta and I rarely drive them. So in short, I think I'm going to be thankful I got some improvement and call the result acceptable, if not great. But I will be researching to see if I can find either an installer with more of a vested interest in my satisfaction level. Or at least a solution for next time, likely the Solo that from ALL reports I've read so far is drone free.

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[buddy guy]

Are the original resonators still in place? Or just the one before the muffler - which really isn't where they work the best.

Not sure if this was for me but yes, original resonators in place. I wonder now too if something as simple as moving the muffler forward would have helped? I note on installing that j pipe the instructions say if the drone doesnt go away, move it forward one inch..try again..move it again.

Darned if i can figure out who I'm going to ask to lean out and move the J Pipe at 65mph? [emoji16]Maybe @Wild one ...earn that name!

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[MADDOG]

Ahead of the muffler. No change in position to muffler

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The muffler is causing the drone. I would think that the resonator, which was put in place to attenuate drone, needs to be at the end of the system as Ram designed it.

 

[buddy guy]

Yet the J Pipe for example in the instructions goes before the muffler as well. I have to think the shop knows that much.

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[Wild one]

Yet the J Pipe for example in the instructions goes before the muffler as well. I have to think the shop knows that much.

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Usually you're pretty limited with where you can place an effective J pipe Terry in a stock exhaust system,all you basically can do is get the shop to make it adjustable so you can length or shorten it a couple inches,then use trial and error to set the length for the least amount of drone.Means you'll get very familiar with what it looks like though,or you can drive faster or slower then the drone won't bother you as much,lol

 

[buddy guy]

I think my pocketbook has had enough of the exhaust fight this year and I'll revisit the whole thing next spring. I'm pretty much at the end of my 1000 dollar truck fun budget for this year. It goes so fast. Lol.

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[hemihustlin]

If theres one thing Ive learned over the years is that drone is subjective and cellphone shot youtube videos do not do justice. The exact same system will have guys saying its the best ever with absolutely zero drone and the next will say it droned to hell and back and he hates it. All sorts of differences come into play, namely driving style and gear ratio. Oh and the terrible MDS, if this is still active on your truck, hello drone!

The absolute worst droning truck Ive ever driven was a nissan titan 5.6 v8 with a magnaflow 14" small round **** side exit before the passenger rear wheel. Would rattle all your teeth and felt like my head was going to implode from the drone. Im pretty sure it had a k and n too probably didnt help.

Meanwhile Ive got my super 10 dumped over the rear axle (no resos no mds) and I find it perfect and simply musical, burbling down the road. I can understand that some people would say it drones but its actually less drone than when I had a muffler delete with factory resos. For me she just purrs, sometimes I even wish it was louder haha

 

[Blstrick55]

I bought my truck used and it has some no name muffler on it that sounds great with no drone. I looked all over it trying to figure out what brand it was but there’s nothing on it. I get asked what exhaust it is pretty often but have to tell people I don’t know. Wish there was a way to find out.

 

[buddy guy]

If theres one thing Ive learned over the years is that drone is subjective and cellphone shot youtube videos do not do justice. The exact same system will have guys saying its the best ever with absolutely zero drone and the next will say it droned to hell and back and he hates it. All sorts of differences come into play, namely driving style and gear ratio. Oh and the terrible MDS, if this is still active on your truck, hello drone!

The absolute worst droning truck Ive ever driven was a nissan titan 5.6 v8 with a magnaflow 14" small round **** side exit before the passenger rear wheel. Would rattle all your teeth and felt like my head was going to implode from the drone. Im pretty sure it had a k and n too probably didnt help.

Meanwhile Ive got my super 10 dumped over the rear axle (no resos no mds) and I find it perfect and simply musical, burbling down the road. I can understand that some people would say it drones but its actually less drone than when I had a muffler delete with factory resos. For me she just purrs, sometimes I even wish it was louder haha

Yeah I gave up on trying to figure drone by cell phone videos. Every one I see that has cab video the owner is stomping the accelerator through the revs then does a final shot of slowing down. What I was looking for was simple. Steady speed examples in the 1500-2000 rpm band. Then I realized there is one non subjective way to test drone. Drop the gear so you all of a sudden are pulling 2000 rpm plus and its like your stuffed ears popping with the sudden relief from the drone sound. Simple.

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[H1Chester]

ARH LT headers, no cats, Corsa Cat back. Zero drone at highway speed, 60mph. I drive this every day.

 

[Blstrick55]

Did some digging and figured it out. I’m about 90% sure it’s a Jones Max Flow MF2278. Only $58 on Summit.

 

[abouttobeglue]

Ive ran Pypes violator 18 inch, gibson mwa, and currently an 18 inch classic chambered powerstick, all are loud around town and minimal drone at highway speeds. I had an 18 inch magnaflow on my 2012 express and it droned more than the glasspack I replaced it with. Pypes m80 I had on my truck at one point droned bad too.