Exhaust Drone

[ENDVR]

Then coil spacers causing driveline angle issues shouldn’t be the issue. Wheel spacers possibly.

I went and drove around during lunch at varying speeds and I am 98% convinced its the exhaust drone. As soon as I would hear it I would either give a little more gas, open the valve, or put it in offroad+ and each time I did that at varying speeds it would pretty much go away every time. I am just dumfounded at why I would notice this now vs. before the lift.

 

[ENDVR]

Has anyone tried the MRT H-Pipe or have you heard anything new from them on developing a system to help eliminate the drone? I am still confused on why I am just now noticing mine but it is unbearable. @MRT Performance

 

[AUSTX]

I just finished installing the Clayton performance coils, teraflex spacer, metal cloak skids, and 1.75" Teraflex wheel spacers and now I have noticed what I thought could be driveline vibrations but reading through some of this, it might be the exhaust drone? I just fine it weird I only started noticing it after the parts were in stalled and only in quiet mode. Here is a video, any thoughts?

Have you dropped the skids to see if it's a reverberation effect?

 

[Keithbickford]

I went and drove around during lunch at varying speeds and I am 98% convinced its the exhaust drone. As soon as I would hear it I would either give a little more gas, open the valve, or put it in offroad+ and each time I did that at varying speeds it would pretty much go away every time. I am just dumfounded at why I would notice this now vs. before the lift.

Interesting for sure. If putting it in off-road makes a difference, it could that you’re hearing the MDS. There’s only one gauge screen page that shows when it is in 4 CYL mode. But it is certainly possible that the distance between the Jeep and the ground is causing an exhaust pulse to hit the ground and reflect upward at the same time the next pulse is also going straight up which results in doubling the sound wave (3dB more)

Has anyone tried the MRT H-Pipe or have you heard anything new from them on developing a system to help eliminate the drone? I am still confused on why I am just now noticing mine but it is unbearable. @MRT Performance

I’m not an ancoustic engineer, but I’ve been studying exhaust for years and am trained in acoustics. Regarding the MRT, less muffler generally equals more drone. Our mid pipe resonator after the x pipe functions like an h pipe since it’s a dual in dual out muffler with both sides sharing the same chamber. So the MRT isn’t going to solve any issues, just make it louder and deeper, which is great for many people. But deeper likely exacerbates drone. 1/4 wave resonators or Helmholtz resonators are the best solution for drone. Next would be a larger dual in dual out muffler. Neither of these will hurt power. Magnaflow is likely the best system for eliminating drone. On our factory system, with the valves open, it’s straight through from catalytic converter to tail pipe. I think a mid pipe with a large dual in dual out muffler and Helmholtz or 1/4 wave resonators would really mellow out the exhaust and eliminate drone.

 

[ENDVR]

Interesting for sure. If putting it in off-road makes a difference, it could that you’re hearing the MDS. There’s only one gauge screen page that shows when it is in 4 CYL mode. But it is certainly possible that the distance between the Jeep and the ground is causing an exhaust pulse to hit the ground and reflect upward at the same time the next pulse is also going straight up which results in doubling the sound wave (3dB more)

I’m not an automatics engineer, but I’ve been studying exhaust for years and am trained in acoustics. Regarding the MRT, less muffler generally equals more drone. Our mid pipe resonator after the x pipe functions like an h pipe since it’s a dual in dual out muffler with both sides sharing the same chamber. So the MRT isn’t going to solve any issues, just make it louder and deeper, which is great for many people. But deeper likely exacerbates drone. 1/4 wave resonators or Helmholtz resonators are the best solution for drone. Next would be a larger dual in dual out muffler. Neither of these will hurt power. Magnaflow is likely the best system for eliminating drone. On our factory system, with the valves open, it’s straight through from catalytic converter to tail pipe. I think a mid pipe with a large dual in dual out muffler and Helmholtz or 1/4 wave resonators would really mellow out the exhaust and eliminate drone.

I am just going to go with the last sentence in your first paragraph. I just drove it 1K miles one way from Palm Springs to Denver and never heard the drone like this. I have had other people drive it who have been in it both before and after the lift and they also agree that this drone was not there before lifting it.

Also, the Magnaflow system seems nice I just wish it tucked up nicer like the AWE.

 

[ParadigmDawg]

I ended up putting a Black Widow, Angry Housewife, muffler on mine. I used their dual inlet/outlet and installed it where the stock resonator was. From there, it dumps out just past the rear axle.

It sounds absolutely awesome and really doesn't drone much.

Oh, and I removed it from my daily driver rotation, and stuck it on a trailer.

We built up our other Jeep for a street/offroad fun Jeep. We call it our city Jeep.

Full Rock Krawler Adventure X series, StreerSmart, Trail Grapplers, Black Rhino, 37s. It turned out great.

 

[Srtmodmaster]

Our droning was so bad when we picked up our JL that it started making us sick! Get it to a good dealer and dump that MDS CAM, LIFTERS AND OIL PUMP and enjoy your hemi the way it should have been built!

 

[tokosmokus]

I had a 392 since 2021 (when it first came out) - no drone. I upgraded it to a final edition in 2024 - really bad drone.
It is absolutely a pain to drive the 2024 version. Anybody interested in a class action?

 

[Canadian 392]

I had a 392 since 2021 (when it first came out) - no drone. I upgraded it to a final edition in 2024 - really bad drone.
It is absolutely a pain to drive the 2024 version. Anybody interested in a class action?

Yes. Absolutely interested.