: Exhaust Vibration - anyone add additional hangars?



DougNuts
08-23-11, 11:12 AM
I've come to the realization that some (or all) of the vibration that I'm chasing is due to the exhaust bouncing up and down under the center of the car.

Has anyone else noticed this and what did you do to fix it?

darkman
08-23-11, 11:50 AM
Is your catback OEM or aftermarket?

tweeter81
08-23-11, 12:01 PM
Take your car to an exhaust shop and have them straighten and clearance your exhaust so it doesn't hit anywhere. I did this, it cost about $70, and the results were well worth it.

Adding additional hangers would do nothing to stop your issues, and I don't even know how you would do that.

DougNuts
08-23-11, 01:41 PM
The exhaust is factory and it isn't hitting on anything. The pipes under the middle of the car are vibrating up and down, which you can feel inside the car. I'll get a video tonight that will explain the issue very clearly.

GDPossehl
08-23-11, 04:03 PM
I'd chance to say something in the drivetrain may be causing those vibrations. How are your motor mounts?

DougNuts
08-23-11, 04:47 PM
I'd chance to say something in the drivetrain may be causing those vibrations. How are your motor mounts?

LOL, that question may be better for my other thread (http://www.cadillacforums.com/forums/2004-2007-cadillac-cts-v-general/233329-2100-2350rpm-vibration-fix-eluding-me.html) where I talk about how I've spent $2000+ to fix a vibration.

Long story short, sure, something is causing my exhaust to shake up and down and send vibes through the car. I want to add a hanger or two behind the resonator to calm it down.

FYI, after adding the transmission mount, I can finally see/feel the vibrations at idle while the engine looks/feels calm. Again, I'll try to get a video tonight to show what I'm dealing with.

tweeter81
08-23-11, 06:07 PM
The exhaust is factory and it isn't hitting on anything. The pipes under the middle of the car are vibrating up and down, which you can feel inside the car. I'll get a video tonight that will explain the issue very clearly.

Again, I fail to see how additional hangers would do any good. You said the pipes are vibrating up and down, then by definition, they are hitting somewhere. If you tweak them so they don't hit that particular spot anymore, then amazingly the sounds and vibrations will go away. I had an issue where my Magnaflow pipes were hitting on the transmission mount under hard acceleration and it was causing a hellacious racket, but the pipes just needed to be adjusted.

If that doesn't help your situation, then something in the drivetrain is making the noise.

DougNuts
08-23-11, 07:10 PM
EDIT: Scratch this whole thread, it's in the engine or transmission. I got under the car with a camera and found that the exhaust isn't moving much, the vibration is 100% chance in the engine or transmission. It's there with the clutch in and clutch out.

CadzillaTN
08-23-11, 09:18 PM
Edit-

I hope it's not the trans!

DougNuts
08-23-11, 11:17 PM
Edit-

I hope it's not the trans!

Yeah, me too. I just went back to the stock mount and everything is back to how it was before, which is only a vibration at just over 2000rpm. I'm just going to live with this until I get a beater or something blows up. :)

I hate to bad mouth the CS mount, but ~800 miles on it and it seems like it went bad on me. I might call them about it just to see what they say.

Sullyfx
08-23-11, 11:53 PM
My exhaust was doing the same thing. I just got under it and hit it a bit to see what the pipes were touching. Turns out they were tapping against a brace about half way down the system. Just 2 bolts and the problem is fixed... I suppose eventually I will put it back on and add some padding of some kind.

CadzillaTN
08-31-11, 10:36 PM
Yeah, me too. I just went back to the stock mount and everything is back to how it was before, which is only a vibration at just over 2000rpm. I'm just going to live with this until I get a beater or something blows up. :)

I hate to bad mouth the CS mount, but ~800 miles on it and it seems like it went bad on me. I might call them about it just to see what they say.

New stock mount or your old one? No one has complained about the cs mount. I'd say it's just supporting the components that are vibrating. My theory is while everything was "hanging" it was muted via less support. So if anything you’re just back to square 1. Doesn’t mean you don’t still need a transmission mount either.

I've had the same feeling for a long time--- bouncing drivetrain, lifting under acceleration, slop, etc etc. I could feel the whole stick shift assembly (transmission) moving on big bumps and highway dips. Dealer always said mount was “fine”. Well, I took it out tonight. Stock, 67k. That thing was SAGGING bad.*sigh* Not sure why didn't I replace this a long time ago even though I was under warranty.. you can’t really tell how bad it is until you unbolt it from the trans. I don't know what height was "normal" but I'd say I had a good 1/4 to 3/8 inch of play before the top side of the mount was 'level'. This has undoubtedly exacerbated some other problems I've had, probably stressing the internals of the trans, the driveshaft, and all 6 of my diffs.

I might just leave the car in the air and attempt removal of the clutch/fw assembly.....never done it, but then again I'd never done anything I've done on the V before I did it, like motor mounts, suspension (5 times), shifter, etc. Seems like it is pretty technical but still possible. I'll go stay at a Holiday Inn Express and read all the past threads!

DougNuts
09-01-11, 11:52 PM
Old stock mount is what I put back in. I e-mailed CS but haven't received a response. There is no doubt in my mind that something went bad with the mount since for 3 days the car was better than it'd ever been and then after a long highway drive, it started transmitting a bunch of vibration from 1000-2000rpm.

You are right about vibration in the drivetrain being transmitted and I've come to the conclusion that this is why GM put so much rubber in there to begin with. In a few months, I'm going to put in new stock engine and transmission mounts and I'd bet $20 that everything feels great after that, but we'll see! :cool2:

Edit: I don't mean to bash the CS part at all, if anyone reads this that way. A lot of people have bought these mounts and I haven't heard any complaints so this may be an isolated incidence with numerous causes.