Muffler elimination/Drone help?

[rcaldwel]

Got the bug and eliminated the muffler friday. Left on the resonator. I do get a drone about 1900 RPM and need some suggestions to get rid of it. I have an extended cab ISB. I put on the US Gear Chrome turn down in hopes of eliminating the drone. I have a good portion of the tip sticking out and it is slightly turned toward the rear bumper (just a bit). Would taking off the resonator eliminate the drone? The sound level without the muffler isn't bad at all, especially if the windows are up. Would the elimination of the resonator be to loud? and or would it cure my drone. ?

Any suggestions would be greatly appreciated. This forum is the next best thing to driving my Cummins.



Thanks,



Bob Caldwell

 

[Straight6Jeff]

I eliminated the muff and resonator on Saturday... . What a difference. The butt dyno says it spools up faster.



I have a regular cab, and it is not too loud inside, with very little drone at speed. There is a little, but with the radio at normal levels, you can't hear it.



I know from my families exhaust business that they had is if a thin wall pipe is used, more noise and drone is present. because the thinner walls resonate easier. I went with a straight piece of 12 ga alumized pipe.

 

[rcaldwel]

muffler elimination/drone

StraightJeff,



Thanks for the quick response. I believe the muffler folks used standard (?) pipe when they removed the muffler.



Did you have any experience (0r anyone else) with first removing the muffler and getting use to the sound then removing the resonsator? Could you tell if there was a significant increase in or outside the cab? Mine didn't seem like the sound increased that much, of course I didn't asked the neighbors their opinion!



If you did remove the muffler first, did you notice a drone and if it disappeared when the resonator came off? Or did it improve or just make the drone worse? I don't want to make the problem any worse thats for sure- I suspect my wife has noticed something different but at this point she is unable to determine what has happened. Hard to explain why you take off things like a good working muffler( she thinks its a "Guy" thing). I do know that she noticed the drone and started asking some questions. I would like to get this fixed before she really begins to get annoyed with the sound of the drone.



I sure enjoy the sound of the muffler being off. Again it doesn't sound that much louder. I also noticed quicker spool up and my EGTs are running about 75 degrees cooler. I will fuel up this week and see if there has been an effect here as well.



Again, if you or any one else has suggestions ( except that I don't want to put the muffler back on) to eliminate or at least decrease the drone I would really appreciate hearing from you.



Thanks Again,



Bob Caldwell

 

[Ramboy]

Some say the way they cured the dreaded drone was to put the resonator back on. Others have changed mufflers, used exhaust clamps, etc. Do a search and you will find a ton of info.

 

[Straight6Jeff]

I used the heat wrench to remove both resonator and muffler at once. Does it seem that the quad cabs have a more pronounced case of drone? Maybe because of the larger "resonance chamber" of the cab? Just thinkin out loud here.





I know this past saturday, Scott from MassDiesel was putting a set of guages in has truck when we started to hear a bass-like thumping noise. The truck was off. Get out of the truck, and you couldn't hear it. Turns out it was the furnace thumpin that was being amplified in the cab.

 

[roadranger]

Originally posted by rcaldwel

Would the elimination of the resonator be to loud? and or would it cure my drone. ?

From what I've read here, you want to leave the resonator on to cut out the harsher exhaust noise.



The drone with the Quad Cabs is because of the longer straight pipe which resonates easier.

The cure for this is to CLAMP on (not weld) a length of thick wall angle iron to the long length of straight pipe.



Hope this helps--let us know how it works out.

 

[Chris N5CWM]

Originally posted by rcaldwel

Got the bug and eliminated the muffler friday. Left on the resonator. I do get a drone about 1900 RPM and need some suggestions to get rid of it.

Did you use the factory exhaust system mounts?

Did the shop use clamps or weld it in?

*edit added*

Is your truck a short bed or long bed? Mine's

a shortbed Quad Cab. *end edit*



I have no annoying drone, even when the windows

are down. Just pure sweet Cummins music out the

tailpipe. Drone is the "resonance" that

reverberates/vibrates the truck and is annoying

and if it's really bad, it can drown out your

radio. Maybe you are just not used to it yet?

If you go further and eliminate the resonator too,

then you will experience true DRONE! I

recommend not doing it.



Mine was replaced with a section of 3. 5" solid

exhaust pipe, and welded in place. Used the

factory rubber isolated exhaust system hangars

and there is basically no drone.



Good luck! Let us know.



-Chris

 

[Dr.Kayak]

I also removed my muffler this weekend. Used the Jenos kit. Don't seem to have a drone. Got all the clamps real tight with an impact wrench. Also used the hanger that the back of the muffler was atached to. Bought an universal hanger kit from Napa and pulled it up real tight.



Over all, it's not much louder but you can't hear the turbo as well. Don't know if I like that.

 

[rcaldwel]

muffler eliimination/drone fix

I took the advice from many readers and installed some angle iron and exhaust clamps last night. I put a long angle iron on the piece in front of the resonator and a smaller one behind it. It did cut down significantly on the drone. There seems to be just a small amount. when you walk around the truck when its at idle, you can hear a deep throat sound coming from the exhaust turn down. the sound doesn't seem to be that much loader before the muffler was removed. I do hear the turbo more and see a decrease in the EGTs of around 75 degrees. I thought I might hear more of a "Big Rig" sound but I am not complaining especially when you come up on a ford or chevy diesel.



Thanks for the input folks. this forum really encourages us too try things which I probably wouldn't do without this type of support.



Thanks Again,



Bob Caldwell