5.7 Hemi Need Help Reducing Drone - JeepForum.com
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post #1 of 21 Old 02-29-2020, 02:35 PM Thread Starter
votive
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5.7 Hemi Need Help Reducing Drone

I have a '05 WK with the 5.7 Hemi. A few months back I decided to replace my exhaust since the stock one rusted through and had 2 pretty large holes in it. I opted with the MBRP system and I am really pleased with how it sounds, but I'm not pleased with the drone.

Anywhere between 1,500 and 2,200 RPM my ears feel like they are bleeding and any passengers I have in the back seat absolutely hate their lives. I regularly drive 2+ hours at 55-60mph and I'm considering going back to stock if I can't get this figured out. I don't think it's the MDS I'm hearing because it drones even with tow/haul mode on.

Is there any way I can modify this MBRP system to retain most of the sound but eliminate the drone? I've thought about swapping the resonator that came with the system for a vibrant resonator but honestly I just don't know enough about exhausts to know if it would work.

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post #2 of 21 Old 02-29-2020, 04:09 PM
90grandoneer
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Welcome to the forum. I am not familiar with the exhaust system you have, but I can tell you that, to keep drone to a minimum, you'll need to have a fairly quiet muffler (I use a Magnaflow) and a good resonator.....no muffler or resonator delete. I have long tube headers and a 3 in. cat. back (Magnaflow 14589 and Xlerator AP XS1229 in the resonator position) on my 5.7 and the drone is barely noticeable, even on a 6-8 hour drive. I will say that I tried 4 different setups before I got it right though. I've had the cat. back on about 9 years and it still works great and easily passes the "wife" test.....fairly quiet at cruise and a pleasant roar at WOT.

06 GCO, Dk Khaki, QDII, Flshing Hi 3rd Bk Lt, MDS "ON" Lt, Airtab Vortex Gens, Debadged, Fumoto Drain Valve, BT Catch Can, Chopped EGR Tube, SRT8 CAI, AFE Air Filter, Sonnax Trans Line Press Booster, SC Tuner W/Adv Trans Tune App, DS and HP tuners, Transgo Shift Kit, ARH Long Tube Hdrs w/3 in Magnaflow/Xlerator AP Exh Sys, Bilsteins, SRT Springs/Sways, Cust Eng Cvr, SRT8 frt/rear bumpers, FRI Sidewinder Cam w/6* advance/6.1 valvetrain, SLP 25% UD Pulley, BBK true 90mm T-Body, SOS Ign Coils w/.060 spark plug gaps, TEA ported/milled heads w/new valve seats, SRT Reps with 265/45&295/40X20's. Also 05 Hemi LX modded exactly like WK and Comp Cammed 06 300CSRT8.
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post #3 of 21 Old 02-29-2020, 11:23 PM
Rtbrjason
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I had that exhaust on my 08 4.7. Same complaint. I tried a 3” in/out flow master in place of the MBRP muffler and it wasn’t really any better. I then added a resonator to the end and it also didn’t help. In the end, I went to mostly stock setup from Dynomax which is still louder than stock but without any drone.
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post #4 of 21 Old 03-01-2020, 04:46 PM
acabtp
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if it's a pretty narrow band that it's happening, you can build a 1/4 wave resonator. google it, there's math required to make it work, but they work well when set up properly. it would leave the rest of the tone pretty much alone and only effect the frequency range (and harmonics of that range) that you build it for.

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post #5 of 21 Old 03-01-2020, 04:48 PM
acabtp
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they're also called J pipes

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post #6 of 21 Old 03-02-2020, 09:12 AM
Arneb04
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Did you guys running the MBRP have the stainless version or the aluminized?
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post #7 of 21 Old 03-03-2020, 10:02 AM
Raffish
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Stainless MBRP.
Installed and took on a long drive.
Almost drove off a cliff to relieve my head.
Mellowed significantly in the last 8 months..
I'd think adding a reso (stock or other) back on would make a difference..

Puts a smile on my face every morning when I turn it over in a small garage...
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05 WK Limited 5.7, QDII, OME HD, 265/70/17 1.25" Spydertrax, CC, MBRP SS, 250xxxkms
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post #8 of 21 Old 03-04-2020, 11:32 AM
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I’m ordering the stainless kit next week for my 4.7L. Maybe it won’t be as bad lol.
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post #9 of 21 Old 03-15-2020, 12:49 AM Thread Starter
votive
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Quote:
Originally Posted by Rtbrjason View Post
I had that exhaust on my 08 4.7. Same complaint. I tried a 3Ē in/out flow master in place of the MBRP muffler and it wasnít really any better. I then added a resonator to the end and it also didnít help. In the end, I went to mostly stock setup from Dynomax which is still louder than stock but without any drone.
Sorry for the late reply, for some reason I wasn't getting any notifications from this post to my email.

Anyways, I was going to try throwing a different muffler on it in place of the MBRP one, but I'm glad I saw your reply. I figured the 4.7's had no drone because everyone on amazon says this exhaust has barley noticeable hum to no drone. Is the roar from the Dynomax comparable to the MBRP when you're stepping on it?
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post #10 of 21 Old 03-15-2020, 01:02 AM Thread Starter
votive
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Originally Posted by Raffish View Post
Stainless MBRP.
Installed and took on a long drive.
Almost drove off a cliff to relieve my head.
Mellowed significantly in the last 8 months..
I'd think adding a reso (stock or other) back on would make a difference..

Puts a smile on my face every morning when I turn it over in a small garage...
I agree, it sounds great at startup especially in a parking garage. When you say it has mellowed out in the past 8 months, how long did you have it before it started to mellow out?
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post #11 of 21 Old 03-15-2020, 01:05 AM Thread Starter
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Originally Posted by Arneb04 View Post
Iím ordering the stainless kit next week for my 4.7L. Maybe it wonít be as bad lol.
I have the stainless. If you do a lot of city driving it's a treat to listen to. Have you ordered it and put it on yet?
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post #12 of 21 Old 03-15-2020, 01:12 AM Thread Starter
votive
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Originally Posted by 90grandoneer View Post
Welcome to the forum. I am not familiar with the exhaust system you have, but I can tell you that, to keep drone to a minimum, you'll need to have a fairly quiet muffler (I use a Magnaflow) and a good resonator.....no muffler or resonator delete. I have long tube headers and a 3 in. cat. back (Magnaflow 14589 and Xlerator AP XS1229 in the resonator position) on my 5.7 and the drone is barely noticeable, even on a 6-8 hour drive. I will say that I tried 4 different setups before I got it right though. I've had the cat. back on about 9 years and it still works great and easily passes the "wife" test.....fairly quiet at cruise and a pleasant roar at WOT.
Did you build the cat back yourself or take it to a shop? If you took it to a shop... about how much was it in labor to get it built?

Do you have any pictures of the system that you could share?
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post #13 of 21 Old 03-15-2020, 07:49 AM
Rtbrjason
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I bought the MBRP based on the reviews as well. It is a good sounding exhaust both on startup and WOT. It’s just too much at or around 2000 rpm cruising.

The replacement muffler (Flowmaster 943050 50 Delta Flow Muffler - 3.00 Center IN / 3.00 Center OUT - Moderate Sound https://www.amazon.com/dp/B000HKXXXO..._fiJBEbS4RG85S) made essentially no difference in the drone.

It’s difficult to compare the new Dynomax stock like setup. I’ve since added a cold air intake, and replaced the cats with resonators. I think a large amount of my roar now is intake related, though the exhaust is for sure louder as noted on startup.


Quote:
Originally Posted by votive View Post
Quote:
Originally Posted by Rtbrjason View Post
I had that exhaust on my 08 4.7. Same complaint. I tried a 3” in/out flow master in place of the MBRP muffler and it wasn’t really any better. I then added a resonator to the end and it also didn’t help. In the end, I went to mostly stock setup from Dynomax which is still louder than stock but without any drone.
Sorry for the late reply, for some reason I wasn't getting any notifications from this post to my email.

Anyways, I was going to try throwing a different muffler on it in place of the MBRP one, but I'm glad I saw your reply. I figured the 4.7's had no drone because everyone on amazon says this exhaust has barley noticeable hum to no drone. Is the roar from the Dynomax comparable to the MBRP when you're stepping on it?
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post #14 of 21 Old 03-15-2020, 01:37 PM
90grandoneer
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Originally Posted by votive View Post
Did you build the cat back yourself or take it to a shop? If you took it to a shop... about how much was it in labor to get it built?

Do you have any pictures of the system that you could share?
The engine is mine is a 5.7 so my setup is probably a little different than yours. I had my complete header back exhaust system built by a shop that does a lot of custom exhausts for classics and hot rods. It was done back in February of 2011 and cost $1400 for everything at the time. I have some pictures of the original setup and I know I have one of the final resonator somewhere but can't find it right now. Below are pictures of the original setup with a glasspack in front of the Magnaflow muffler and one in the resonator position. There's also a pix of the headers he built (the silver ones) and the current American Racing headers that are on it now.
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06 GCO, Dk Khaki, QDII, Flshing Hi 3rd Bk Lt, MDS "ON" Lt, Airtab Vortex Gens, Debadged, Fumoto Drain Valve, BT Catch Can, Chopped EGR Tube, SRT8 CAI, AFE Air Filter, Sonnax Trans Line Press Booster, SC Tuner W/Adv Trans Tune App, DS and HP tuners, Transgo Shift Kit, ARH Long Tube Hdrs w/3 in Magnaflow/Xlerator AP Exh Sys, Bilsteins, SRT Springs/Sways, Cust Eng Cvr, SRT8 frt/rear bumpers, FRI Sidewinder Cam w/6* advance/6.1 valvetrain, SLP 25% UD Pulley, BBK true 90mm T-Body, SOS Ign Coils w/.060 spark plug gaps, TEA ported/milled heads w/new valve seats, SRT Reps with 265/45&295/40X20's. Also 05 Hemi LX modded exactly like WK and Comp Cammed 06 300CSRT8.
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post #15 of 21 Old 03-16-2020, 08:49 AM
Arneb04
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Originally Posted by votive View Post
I have the stainless. If you do a lot of city driving it's a treat to listen to. Have you ordered it and put it on yet?



I have not. Reading all the discussion here I have become very leery of going for the MBRP. I do a lot of highway driving while towing and I'm thinking if the drone is actually as bad as what people say, it stands to reason that under a significant load it will be worse and I don't know that I want to commit to that. I might just continue to read this discussion as it evolves before making the buy. Some rims that I was interested in became available, and since they're 18" I'll need to put tires on them so the exhaust will wait for a bit I think. Need to deal with my struts at some point as well. Always a list
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