2nd Gen Non-Engine/Transmission Exhaust Drone cured - well almost

[JimKing]

Someone who replied to my last post, Sorry I can't find the name, suggested attaching 2X2 angle to the straignt parts of the exhaust system would help with the deafening noise at 2000 rpm. After some experimenting I found it really works. I have 4 pieces of 2X2X1/4 iron angle each 24" long clamped the length of the pipe from the first straight section to just behind the muffler.



I found that 4 screw clamps per section keeps it tight, and a small groove for the clamps made with my 1/2" grinder keeps it all from moving around. Noise is decreased remarkably, exhaust note is unchanged, but the harmonic is nearly gone. All the pieces are on top of the pipe, so I don't drag them off. Simple but effective way to preserve whats left of my hearing.



Lastly. I am installing my FASS this weekend. After prefitting last night, I am a little leary of the brackets supplied. Anyone having trouble with the brackets on 2001 SB/QC ?? I am thing of adding additional support to mine. Doesn't seem like much support for such a hefty pump.

 

[Dkevdog]

Jim- I tried that same experiement with very little if any success. Where I solved my problem was moving the muffler forward toward the firewall and putting the straight pipe behind it. It has done very well for me, but I'm sure each system is going to respond a little differently.



Kev

 

[TomGolden]

I have also band clamped 2x2" angle iron all along the straight sections of my 4" exhaust, and it did nothing that I could tell. I also bought a 50' rool of exhaust header wrap from Great Southern Insulation and overlapped it so it is actually 2 layers thick along the same straight sections, all the way up to the turbo, and that did make a noticeable difference.



Tom

 

[Bodybomber]

I put a 2ft piece of angle iron on the straight pipe and it helped. But what realy helped was putting a couple pieces of 1x1 on my JRE muffler.

 

[JimKing]

Update

I tried clamping the angle with screw type clamps, but they worked loose, so I used stainless banding and double crimped it. Better, but it still works loose. Around town it was OK, but after a long trip, I could hear it vibrating when idling. Checked the straps and they are loose. I'm thinking the exhaust heat is expanding the pipe and loosening the fit. I don't want to weld it on. I am thinking I may take it off and move the muffler. I have a good 4 feet of pipe forward of the muffler, the muffler is only 6" diameter, so I have clearance. The angle is a inexpensive fix that works for me, but I don't want to have to tighten it up every week. Is the exhaust wrap rugged ?? Will you rip it off going offroad ??

 

[jandtjil]

Ditto on the exhasut wrap Tom G

Next time go here, no one beats their prices (that I have found anyhow, great service too!)

http://store.hamiltonmarine.com



Jim. If you drag the exhaust, Yes you could snag and it may slowly come undone.

They sell stainless bands to secure it, but large hose clamps are superior in my opinion.

Be sure to purchase the high temp silicone spray to seal the wrap once installed. I think I purchased the silicone through Summitt racing or somewhere else. . my . 02





JJ

 

[bayvalve]

you guys have mufflers!?







thanks for the tips guys... I get the drone at about 49 to 51 MPH, anything more or less, and it goes away, I guess I'm lucky.



"if its too loud, you're too old. "

 

[vette75406]

drone

I just put a Rip Rook Magnaflow Exhaust on my 2000 qc cab 4x4 and after the install I had a little extra vibration in the dash area that caused some noise on acceleration not bad just a little annoying , well being that I work at a GM dealer parts dept. I know what GM uses to fix there exhaust drone problems , and that is parts number #10199232 ,this is a metal bb filled tube with a bracket that clamps to the exhaust pipe , our dealer usually welds two of these together and clamps them along the pipe until the noise goes away , we also have a kit where we install a flex pipe in line but it would be too small for a ctd , . anyway having access to the parts I tried it out to see if it fixes my noise /vibration problem , I just installed the weight on the pipe under one of the clamp bolts, next to the cross member closest to the turbo , this took out about 80% of the vibration/ noise with just one weight I have not gotten around to bolting one another one (rain) , to see if it is a 100% cure . be forewarned if you want some of these the price is about 30. 00 each and that is the good guy discounted price. Not every body can just test drive them and put them back on the shelf , personally the noise is not bad enough for me to pay the employee price for the weights ,others may need them more than I do .





____________________________

2000 QC 4X4 LB AUTO 3. 54 RHINO HUSKY MAGNAFLOW SS LIGHTFORCE AND WHATEVER ELSE I CAN AFFORD SOON

 

[DHoleman]

First time reader of this post, I don't have the 4" exhuast yet but have or can you turn the tail section of the pipe just a tad up or down to say tighten the whole pipe itself, like put it in a bind,maybe that might help..... maybe .

DHoleman

 

[Gary - K7GLD]

The lead post mught be referring to a thread I started some time back - I had an annoying raspy BUZZzzzz at around 1900 RPM when pulling hard in grades with our 5er - figured it was a vibration/resonance in the exhaust system due to excessive runs of pipe that vibrate like a guitar string at certain resonant frequencies. I attached about 3 feet of HEAVY WALL angle iron at the longest run between the factory resonator and downpipe to physically alter the resonant vibration frequence outside my power band, clamped it securely to prevent flexing...



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This has eliminated MY problem - and apparently a few others as well - I also attached a standard exhaust support strap between where the front pipe clamp attaches to the muffler, using a second clamp, and the truck frame - rotating this clamp allows me to adjust tension on the exhaust system at this point to further restrict vibration and movement...



#ad




Might not LOOK elegant, or solve ALL vibration/drone problems, but sure fixed MINE!



Besides, not that many folks get under my truck to critique my various mods anyway...

 

[JimKing]

My problem exactly. 1900-2000 RPM under a load will drive you right up the wall, and you can't drink a cup of coffee because you can't keep it in the cup. My angle worked, but I cant keep it tight. Where did you get the clamps ??

 

[HEYBOSS]

OK. So what's up with this drone? Mine is real bad at 2000rpm

Tried different exhaust and no help. The drone has been there since new but with bigger exhaust it's worse.



Has anyone figured out why some trucks have it and others don't ?Can anyone come up with a real answer? I'm planning on doing some NR inside cab and some exhaust changes to hopefully reduce it as much I can.



It sure would be nice if someone came up with some miracle kit that would cure it for good

 

[Gary - K7GLD]

"Where did you get the clamps ??"



I made my own out of all-thread and some flat 1/4 inch stock for the plates the all-thread passes thru - they DON'T loosen!



As to what CAUSES the drone, I don't care whatt anyone sez, its RESONANCE in the exhaust system that occurs at the peak of the power band because the entire exhaust system "floats" loosely on rubber and tends to vibrate like a guitar string at that resonant point.



As can be seen, MY "fix" is to CHANGE that resonant point or eliminate it by RESTRICTING motion and adding stiffening and weight to the exhaust system sorta like wrapping lead around a guitar string will alter it's pitch/frequencey. This will help MECHANICAL vibration - but AUDIO resonance due to various lengths and diameters of specific exhaust systems is another animal altogether - like a 'tuned" exhaust on a racing bike!

 

[WOT]

I got Rip's 4" diamond eye system & had drone between 1600-2000 RPM. Rip had me put another muffler on and it is completely gone now.

 

[HEYBOSS]

Why

Some trucks have it and others don't?????



I've driven trucks that are absolutely drone free even with big exhaust and mine will drive you nuts.



Also wondering, does Ford and Chev drone too or is it just the CTD's?



Another idea I was kicking around to add a gear spliter so will get you out of the rpm/drone range! Will it work?





Fred.

 

[Gary - K7GLD]

I think it's a characteristic more peculiar to an inline 6 - firing pulses are farther apart, and when the turbo spools, camshaft kicks in, BIG things really start happening under the hood...



The same jackhammer firing impulses are supposedly also responsible for other stresses throughout the drivetrain, especially the transmissions...



V8 firing impulses are closer together, and resonant frequencies apparently far enough off that it hasn't seemed to be a problem at the same level as the Cummins...

 

[Forrest Nearing]

I have no idea why they're so different... my truck's worst resonance point has always been 2500rpm... with the stacks, with the straight pipe under the truck, with a resonator, with a muffler, etc.



obviously the severity of the resonance changes with different configurations and muffling, but the resonance point seems to be static... I can't call it... it's baffling to me to hear people talk about their bad resonance at 2,000... I mean, mine resonates there, but at 2500 w/ a straight pipe, it'll split your eardrums! LOL!



Forrest

 

[tmccormick]

Here you go:



https://www.turbodieselregister.com/forums/showthread.php?threadid=91390&highlight=exhaust+drone



Glad to hear that it is working for some

 

[TomGolden]

Before I removed the muffler and went straight piped 2 years ago, I never had any cab drone or resonance, but now from 1900 - 2200 RPM it is absurdly loud in my cab.



Gary - that is some SERIOUS angle iron, man! I might have to try that.



I fantasize about going with stacks this summer, so not sure I want to try anything else with the exhaust just yet.

 

[Gary - K7GLD]

Yeah Tom - I did that mod after the first time out with the trailer, a year and a half ago, towing up your way above Placerville going to Pollock Pines - pretty loud - I did the angle iron bit, and posted a thread and the pics shown up above over in the DTR where I was hanging out at the time - thought it was posted over here too, but I couldn't find it...