Exhaust Drone

[MaLuco]

Hi Canadian 392 I re-sent to John and sent a similar message to another few relevant people at Jeep/Stallantis: https://share.cleanshot.com/Sz0tl64Q

You know.. one would assume people at the top are the ones wanting to be closest to their customers. Let's see. If there is no reply in the next few days there are quite a few more people that could be reached. I hope soon we'll get lucky.

FYI the drone in my 392 has subsided enough (NoLimitz) to enjoy it and to crave even more the drone free experience.

 

[Canadian 392]

Hi Canadian 392 I re-sent to John and sent a similar message to another few relevant people at Jeep/Stallantis: https://share.cleanshot.com/Sz0tl64Q

You know.. one would assume people at the top are the ones wanting to be closest to their customers. Let's see. If there is no reply in the next few days there are quite a few more people that could be reached. I hope soon we'll get lucky.

FYI the drone in my 392 has subsided enough (NoLimitz) to enjoy it and to crave even more the drone free experience.

MaLuco .

Brilliant work on the email fronts! I trust Jeep will prioritize its reputation, and communicate with us, their customer base on such an important matter.

I have read about your use of the NoLimitz device. I have yet to consider this option.

I hope Jeep does the right thing here and reply, appropriately, and with a solution to our affected vehicles.

 

[MaLuco]

Other ideas:

• Jeep tuners or shops, such as: amw4x4.com, aev-conversions.com or zautomotive.com themselves
• mechanics / youtubers, such as: youtube.com/@wayalife, youtube.com/@DIRTROADCRED, youtube.com/@Jason-Samko, youtube.com/@DEBOSSGARAGE, youtube.com/@TFLoffroad
• we could even try Doug DeMuro

If not for their expertise on the issue, then perhaps on becoming our allies to talk to Jeep.

Does anyone have any relationship with any of them?

 

[Canadian 392]

Hello, everyone! If you are currently experiencing this concern and would like our assistance, please do not hesitate to send us a private message.

Yenori
Jeep Cares

Hi Yenori,
Please update the customer group here about what has been done on your end and with Jeep to generate a solution for the drone problem for affected vehicles.

I understand you are have suggested sending a private message, however, I believe (and others will agree) it is in the best interest of the customer base in the USA, Canada and Elsewhere to have the benefit of a Transparent Solution that will benefit all affected vehicles.

Thank you.

 

[MaLuco]

Hi Yenori,
Please update the customer group here about what has been done on your end and with Jeep to generate a solution for the drone problem for affected vehicles.

I understand you are have suggested sending a private message, however, I believe (and others will agree) it is in the best interest of the customer base in the USA, Canada and Elsewhere to have the benefit of a Transparent Solution that will benefit all affected vehicles.

Thank you.

I am happy to share here openly on the forum my vehicle details that can help diagnose the problem (including last 6 digits of the VIN code). Thanks a lot @Yenori. We appreciate a lot your commitment to help us.

 

[Canadian 392]

I am happy to share here openly on the forum my vehicle details that can help diagnose the problem (including last 6 digits of the VIN code). Thanks a lot @Yenori. We appreciate a lot your commitment to help us.

@Yenori

I am also happy to share the same info to help diagnose the problem and develop an appropriate solution for the benefit of the Group.

 

[Canadian 392]

Hello, everyone! If you are currently experiencing this concern and would like our assistance, please do not hesitate to send us a private message.

Yenori
Jeep Cares

Hi Yenori,
Following up here.

Please update the customer group here about what has been done on your end and with Jeep to generate a solution for the drone problem for affected vehicles.

I understand you are have suggested sending a private message, however, I believe (and others will agree) it is in the best interest of the customer base in the USA, Canada and Elsewhere to have the benefit of a Transparent Solution that will benefit all affected vehicles.

Thank you.

 

[MaLuco]

Hi Canadian 392 / Team. A quick update form my side.

• I have messaged and followed up with the Jeep executives (via Linkedin) to no avail. Bob Broderdorf did connect with me but exchanged no content so far. I choose to hope they take their time with their teams to figure it out before replying.
• ZAutomotive is an awesome company (more on this at another time)
• I have written to the aforementioned gurus/influencers for advice and support. Let's see

 

[Ernesto]

Hi MaLuco,
Wondering if John at Jeep has replied to your email from last week.
Please let us know.
Thanks!

I just discovered Off-Road+ mode. This deactivates 4 cylinder mode in my 392 at least.

 

[Changster]

I am another Canadian 2024 392 droner! It's not that annoying but it clearly isn't right. Its a pity as other than that its amazing.

 

[Canadian 392]

Hi Canadian 392 / Team. A quick update form my side.

• I have messaged and followed up with the Jeep executives (via Linkedin) to no avail. Bob Broderdorf did connect with me but exchanged no content so far. I choose to hope they take their time with their teams to figure it out before replying.
• ZAutomotive is an awesome company (more on this at another time)
• I have written to the aforementioned gurus/influencers for advice and support. Let's see

Hi MaLuco,
On behalf of the group, Thank You for the update.

I trust Jeep Corporate will do the honorable thing and help out affected customers on this being their "halo" Wrangler.

 

[Keithbickford]

For me, it only drones when it goes into 4cyl mode. That’s the only way I can tell it’s in 4cyl mode, and why I hate that mode so much! The Tazer NoLimitz JL prevents it from going into 4cyl mode, and therefore prevents the drone.

Debating MDS and if electronically disabling it is a whole other discussion. I hope to completely remove that system at some point with a new cam, etc.

The NoLimitz module allows disabling the MDS.

 

[Keithbickford]

Is yours a 24 ? Is there an indicator that shows when it goes into that mode ?

Yes. It’s in your fuel economy gauge. Also be mindful there’s to modes to that gauge. One shows when it goes into 4 CYL, and the other does not. Toggle left right while in the colorful fuel economy gauge.

 

[Keithbickford]

Hi Everyone,

I have a 2024 392 with this drone issue from about 1500-2000 RPM, whether it's light throttle in this range, and especially on deceleration, regardless of having Offroad + on or off. A low range very loud deep boominess between 45-70Hz. This Occurs with sport exhaust on or off, but a little less with sport exhaust turned off. This drone can actually be painful.

It is not the active noise cancellation. I have disconnected the mics in the roll bar, and disconnected the subwoofer, and even pulled the fuse to the stereo to rule out the active noise cancellation. Makes no difference, the drone is still there.

Supposed "no drone" exhausts from AWE and Borla Atak and S-type do NOT improve this problem.

Dynamat/Dynapad does nothing.

The pre-2024 model years do not appear to have this problem, or at least not nearly as often. Apparently, some 2024 models do not have this issue, which leads to me to believe there a problem with our examples which exhibit this really bad drone problem.

I believe there must be some type of engineering changes, whether they be acoustically with the exhaust, or some type of computer calibration etc.

I think this needs to be taken up with Jeep corporate.

Jeep must be accumulating data on this since it's becoming a wide-spread problem for the 2024 model year.

It appears not all 2024 392 have this problem, but for the many unfortunate ones that do, it's a really big problem.

This thread, and similar "exhaust boominess" threads are prevalent on the "other" Forum as well (I am not sure if the rules allow us to link other related forum websites).
Has anyone communicated with Jeep?

Has anyone resolved this issue?

I’m a firm believer in quarter wave resonators in the exhaust. Also called Helmholtz resonators. Magna flow uses these in the exhaust made for our 392. I installed quarter wave resonators on my Toyota tundra, and it completely killed all exhaust drone, but it also smoothed out the exhaust sounds so much it no longer sounded like a V8 engine. The magna flow does not seem to have this issue.

 

[Canadian 392]

I’m a firm believer in quarter wave resonators in the exhaust. Also called Helmholtz resonators. Magna flow uses these in the exhaust made for our 392. I installed quarter wave resonators on my Toyota tundra, and it completely killed all exhaust drone, but it also smoothed out the exhaust sounds so much it no longer sounded like a V8 engine. The magna flow does not seem to have this issue.

I have experimented with j-pipes (1/4 wave resonators) from varying lengths, 30" to 86". The longer j-pipes helped to attenuate the low end frequencies near 50Hz in the 392, @ about 1600 RPM but in doing so, the higher frequencies around 110Hz @ 2200 RPM were not being attenuated anymore and were then amplified. I tried to find a "sweet spot" between the 2 frequency areas, but it was still a problem. It's a double edge sword. I used the exhaust temperature readings with a laser thermometer, frequency analyzer, and the statistical tables as indicated in the this popular website: strikeengine.com/helmholtz-resonator-calculator-exhaust-j-pipe-length

This only resulted in a partial improvement but really, not that effective, at least for my example of this 392. There must be more to the drone puzzle here as I too was expected a marked improvement with the 1/4 wave resonators.

 

[Keithbickford]

I have experimented with j-pipes (1/4 wave resonators) from varying lengths, 30" to 86". The longer j-pipes helped to attenuate the low end frequencies near 50Hz in the 392, @ about 1600 RPM but in doing so, the higher frequencies around 110Hz @ 2200 RPM were not being attenuated anymore and were then amplified. I tried to find a "sweet spot" between the 2 frequency areas, but it was still a problem. It's a double edge sword. I used the exhaust temperature readings with a laser thermometer, frequency analyzer, and the statistical tables as indicated in the this popular website: strikeengine.com/helmholtz-resonator-calculator-exhaust-j-pipe-length

This only resulted in a partial improvement but really, not that effective, at least for my example of this 392. There must be more to the drone puzzle here as I too was expected a marked improvement with the 1/4 wave resonators.

You could try a muffler on the J pipe. That reduces the Q factor which causes it to attenuate a wider frequency range, but not as much at the center frequency. Essentially a wider and shorter bell curve.

 

[Keithbickford]

I have experimented with j-pipes (1/4 wave resonators) from varying lengths, 30" to 86". The longer j-pipes helped to attenuate the low end frequencies near 50Hz in the 392, @ about 1600 RPM but in doing so, the higher frequencies around 110Hz @ 2200 RPM were not being attenuated anymore and were then amplified. I tried to find a "sweet spot" between the 2 frequency areas, but it was still a problem. It's a double edge sword. I used the exhaust temperature readings with a laser thermometer, frequency analyzer, and the statistical tables as indicated in the this popular website: strikeengine.com/helmholtz-resonator-calculator-exhaust-j-pipe-length

This only resulted in a partial improvement but really, not that effective, at least for my example of this 392. There must be more to the drone puzzle here as I too was expected a marked improvement with the 1/4 wave resonators.

You might be more of a nerd than me!

 

[Canadian 392]

You might be more of a nerd than me!

I have been trying everything to remedy the problem. Even the dealership foreman says the drone is "loud and untolerable" and they have been unable to help, at all. The solution needs to come down from Jeep engineering....

 

[Keithbickford]

I have been trying everything to remedy the problem. Even the dealership foreman says the drone is "loud and untolerable" and they have been unable to help, at all. The solution needs to come down from Jeep engineering....

Wow. That sucks. Mine is a 2024 too. Knowing that you’re an intelligent person, I know you’ve ruled out the MDS.

Especially with New, I noticed the MDS vibrated my seat when active. So annoying. That suggests that the engine is not balanced when the MDS is active.

 

[Canadian 392]

Wow. That sucks. Mine is a 2024 too. Knowing that you’re an intelligent person, I know you’ve ruled out the MDS.

Especially with New, I noticed the MDS vibrated my seat when active. So annoying. That suggests that the engine is not balanced when the MDS is active.

Correct. The MDS has its own kinetic and harmonic signature, which is not the drone issue we are tackling.
Thankfully, I avoid the MDS issue by paddle shifting. Either paddle shifting or activating Off Road + keep the the MDS from engaging.