Exhaust resonance

[Guest00]

As you know the stock injectors and no mods I had no problem. The 4" exhaust caused the problem bone stock. A few days after the 4" went on I installed DD1's and boost module and elbow. Problem still there. Tuned out the resonance by mega clamping the exhaust. Upgraded the injectors to DD2' and again have the problem but at idle to 2,000 rpm range instead of the original 2,000 rpm and up range. I am concidering going back to stock exhaust minus resonator and muffler and just using the 4" muffler. Also concidering going to the 3 piece ex. manifold.
As this problem is rare and is not limited to just one model year, one brand or tubing type it has to be some thing with the engine construction or programming. I will try next week to get my ecm re-flashed and see if the resonance changes.

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2K, 2500,Laramie,Quad,4x4,3:54LSD,auto,reese 15k 5th slider, EISLEY BULL BAR,WESTIN NERFS, TA's,9000's, DD2's,PE-EZ & elbow, ISSPRO pyro & boost, Turbo Lifesaver, JARDINE 4", DTT VB,TC and COOLER, PAC BRAKE, MAG HYTECH TP& DC, onboard.
pullee #1 26' Arctic Fox 5th
#2 22' car hauler w/ 76 Pinto 392cid or 68 Cyclone GT Cobra Jet FB
NRA,VFW,SASS

 

[Tom W]

It seems this problem exists on some trucks and not on others. I'd like some feedback to see if there is any thing in common on those that have the problem.
The resonance occurs over 2000RPM under power and goes away when you let off the throttle. It is a deep, penetrating resonance that is very noticible. If you are not sure then you probably don't have it.
I have played with the exhaust system with little success. I think there is some other cause.
I would appreciate any feedback to help find out the cause and fix.
Thanks, Tom W


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Tom W in Austin Tx 98 24v 2500 Quadcab, auto, 3. 54, lsd, Rhino, white/driftwood, Banks Stinger Plus, Manix grill, nerf bars , DTT's TC, valvebody, cooler, Mag-hytec trans & diff, Pac brake.

 

[Tom W]

It will be interesting to hear more about Marco's ECM. Maybe he'll have a fix.

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Tom W in Austin Tx 98 24v 2500 Quadcab, auto, 3. 54, lsd, Rhino, white/driftwood, Banks Stinger Plus, Manix grill, nerf bars , DTT's TC, valvebody, cooler, Mag-hytec trans & diff, Pac brake.

 

[Jonz]

I have the same problem. It's not really a problem just bothersome. Occurs right at 2100 rpm like clock work. When towing it can be very annoying because I tow right at that rpm for days. Could it be the muffler type? Anyone with the Banks Powerpack having the same results?

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2001, 2500 Black 4x4, Bank PowerPack, DTT T/Q and VB, K&N. Max Boost about 38lbs Pulling a 9000 Weekend Warrior full of dirt toys for the whole family.

 

[mikel]

Howdy,

Seems like I read that someone had some luck cutting out a section of the exhaust right behind the turbo and replacing it with stainless flex pipe (Kinda like the big trucks use??). Anyhow, I did the straight-pipe exhaust and my truck would run me out of the cab at 70-80. I went ahead and put in a walker muffler and it helped allot. I think it's the exhaust system vibrating in harmony with the engine. Adding or moving weight to it will change the frequency it tends to resonate at and may help.

When I have some time I am going to explore the flex pipe option.

Mike

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'99 QC 2500 SLT Driftwood 2wd SB 24v Auto 3. 55 LSD
ISSPRO pyrometer, Walker 21468, 20,000 miles 12-19-00

-- email address removed --

Howdy Agg's!

 

[Ramboy00]

I didn't have any problem when stock so I don't think it has anything to do with the engine. Mine only became noticeable after installing the Banks. Mine sounds more like extreme noise from the exhaust than any kind of resonant vibration. Not noticeable at 70 mph when empty but will drive you out of the cab at 80-85 mph. Haven't towed yet so don't know about sound when loaded.
Phil

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'99 D3500, auto. ,2WD,3. 54, all options, Banks Power Pack w/K&N filter, '99 40ft. Alfa Gold Triple-slide 5'er

 

[Kent Kuykendall]

JNUTTER,

I see from your sig. that you are useing DDII's and EZ. Do you get much low end smoke out of this combo? Also are you r DDII's the Black ones or the grey ones?

Thanks

Kent