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07-23-2011, 05:00 PM #1
Brand New Custom Exhaust System Question
So, I just got my new pacesetter long tube headers installed with a true dual custom exhaust and it hard mounted to the frame. I noticed while driving 70-80mph and if accelerate between those speeds I get a really bad vibration as its coming from the exhaust. Should the exhaust be vibrating like this? this will be my 3rd trip back to the exhaust shop to try to get it fixed right again, i think i am going to tell them to do away with the hard mounting setup as I hate the vibration that comes with it. Has anyone else ever had this problem with a hard mounted exhaust setup?K1500 5.7L Chevy Suburban
Black Bear Performance Tune
TCI Servo and Shift Kit
Long Tube Ceramic Pacesetter Headers
Custom Side Swept Dual Exhaust
Dual 2.5in electric DMH Performance Exhaust Cutouts
BFG A/T 285s
07-23-2011, 05:17 PM #2
07-23-2011, 05:28 PM #3
I'm assuming by hard mounting your saying they welded the pipe hangers directly to the frame with no rubber insulators?
If so yes this could cause vibration, probably cause cracks on the exhaust piping too after a while, theirs no place for the system to flex when the engine torques under load.
I'm surprised a shop would weld the system in like this, I've honestly only seen one other exhaust welded directly to the frame and it was by a back yard mechanic that had very questionable mechanical skills.
The rubber insulators between the hanger points and frame are there to stop excess stress and vibration, the system needs to move a little independantly of the frame.
07-23-2011, 05:47 PM #4
X2 what Mike and Tim said.:cool:
2005 Chevy Silverado Z71 Crew Cab
6" Skyjacker lift w/Edlebrock dual front remote resoviour shocks, single rear remote. Rancho skid-plate.
17" x 9" M/T Classic Lock Wheels, 35" BFG A/T or M/T tires
4.10 PercisionGears w/factory locker, T/A Performance rear-end cover
Banks CAI intake, ported throttlebody, JBA coated headers, over-sized Magnaflow cats, Magnaflow cat back exhaust, Diablo tuned
B&M aluminum deep transmission pan
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Weather Tech floor mats
Cover-Craft seat covers
Dash mat cover
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One black Lab in rear seat.
07-23-2011, 09:10 PM #5
My bad, I didn't clarify what I meant by the hard mount. They used a piece of metal that is welded to the pipe and then attached to the frame by rubber mount. The vibration is off and on when I am driving, at times it vibrates a lot and then its gone. Im guessing one of the mounts may be rubbing somewhere?
07-23-2011, 10:36 PM #6
Maybe spray some WD40 on the rubber mount? Also, how old are your rubber exhaust mounts?04 ECSB Custom silver & grey, Soft 8's, BFG KO's, ReadyLift Leveling Kit, Hellwig front sway bar, K&N filter, DeeZee EZ-Down, Rhino liner, Alpine CDE103BT, Rockford 6.5's, 12" V.A.T. Hammer Pro in a Subthump box, Alpine PowerPack amp, Hifonics amp, BackRack w/ 55w 5000k HID KC Daylighters, KC light bar with 4 KC Slimlites, UWS toolbox, Shaved Antenna mod, Black Bowtie, LED backup, license plate, dome lights & 3rd brake light
07-24-2011, 12:21 PM #7
As willbradfan pointed out the isolators could be stiff since their new and not broke in yet and not allowing as much flex as they should.
Petroleum based lube on rubber parts speeds up deterioration of the rubber, try using a teflon spray or graphite on the isolators where they're attached, the exhaust needs to move at least a little, if it cant move the vibration will be telegraphed right to the drivers seat.
07-26-2011, 11:33 PM #8
So i the exhaust shop finally fixed the problem. They said my engine was putting out too much power for their rubber mounting brackets that caused the metal part of the bracket to break the rubber allowing metal on metal vibration. They fixed by using the oem exhaust mounts. I haven't had a problem since
Now I just have a backflow pressure problem i think...takes a few seconds for the engine get going at first and then it just takes off like nothing happened, this only started happening after the longtube headers and exhaust were installed
Last edited by willbradfan; 07-26-2011 at 11:35 PM.
07-27-2011, 12:59 AM #9
07-27-2011, 07:45 PM #10
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