My exhaust system gives a lot of interior noise. At the right rpm and load, everything seems to vibrate. I crawled underneath to check for rubbing. Nothing. The system hangs nicely and doesn't come in contact with anything. I punched the muffler with the heel of my hand. It was like hitting a tuning fork. The whole thing resonated for a good 15 seconds. No wonder it's so loud inside.

My exhaust is clamped instead of welded. Should welding it make any difference? The joints look pretty good to me, no movement.

There are braided stainless steel exaust couplings that are intended to stop vibration. Anybody have experience with these? I've never seen one in 4" diameter before.

:rolleyes:

never used them before, but have seen them on ricers alot, I don't have a muffler on mine, it went away when I put 3" pipe on.

the flexies are just that they allow the engine in a front wheel drive to rock forward and back without the exhaust breaking off not needed on our vehicles and i have never seen a 4" one either

makes sense, some of those 4 banges seem to roll around in the engine bay.;)

What else could I used deaden the vibration?

I thought you used exhaust doughnuts for that..?

You could clamp some sort of weight to the pipe somewhere to change is natural frequency. The other thing I have heard of is to clamp a length of angle iron to the pipe to also achieve a change in the natural frequency.

Joi,

Are you sure that your pipe isn't touching the crossmember that the torsion bars go through? I had quite a lot of cab noise on my extended cab K2500 until I found out that was the problem. I had welded all the joints and hung the pipe so it didn't make contact and as the rubber hangars stretched it made contact again. I finally heated the area of the pipe by the crossmember and gave it a good whack with a B.F.H. to give it a clearance dimple. All in all, if I had to do it again, I would have gone with JK's 3.5" system.

If you need pictures let me know and I will crawl under with the camera.

I'm sure it's not touching. It was when I first installed the system. Then it was reeeaaallly loud inside. Now it's not as bad, but that resonance is definitely there. I'm going to experiment a little with weights, angle iron what ever I can find.

What's an exhaust donut? I wonder if I can use a wax toilet seal;)

Are you talking about that exhaust drone referred to here:

http://www.dieselplace.com/forum/showthread.php?t=24776&highlight=drone

Can you feel it in the accelerator pedal? Just wondering because I have a vibration that I'm trying to figure out.

My 3.5 makes my ears rattle too. I was tinking about adding a muffler to mine too to change the frequency if at all possible. I also wanna guiet mine down too a little.

I also wanna put a muffler on my turbo if possible. That thing makes my eyes water it makes so much noise.:D

Are you talking about that exhaust drone referred to here:

http://www.dieselplace.com/forum/showthread.php?t=24776&highlight=drone

Can you feel it in the accelerator pedal? Just wondering because I have a vibration that I'm trying to figure out.

I think this may be EXACTLY what I need. THANK YOU!!

I can't say that I feel it in the pedal. I can feel it in my bones though...no kidding either:eek: .

May need to use a resonator close to the engine to eliminate exhaust drone.
Have you checked your muffler bearings? Some shops are now using the high temp teflon coated bearings. For extreme high temp mufflers ceramic coated bearings seem to hold up best. Stainless mufflers work best with stainless bearings in salty enviroments plus the fact they are smaller in diameter and allows you to have a larger bearing ID. When a Johnson Rod is used no bearings are required. Some hotrodders are putting a reverse axial flow inverter in the exhaust right behind the turbo to cut down on the swirling effect of the exhaust going down the tube. In effect reducing the swirling effect of the exhaust thus longer bearing life. Some claim this improves mileage like the tornado device they put in intakes.
I like to use a bronze sleeve in a stainless tubing but that requires removal of the cat. Some people gut the cat, like to see some Pics of that.

Muffler bearings have less than 9,000 miles on them. Had them replaced under warranty at 92,000 miles. When they went, it was more of a rattle than a hum....

How does the exhaust exit the rear quarter? I noticed mine was the loadest when exiting at a 90 to the side and didn't stick out to much. The best is now that it exits at a 45 and sticks out slightly. All that noise is directed more rearward and out past the underside of the pickup.

Got a part # for those teflon coated muffler bearings? I havent had good luck with the bronze bushings.......):h

Got a part # for those teflon coated muffler bearings? I havent had good luck with the bronze bushings.......):h

OK what are muffler bearings??? I have heard this once before and thought it was a joke. Where do these comes into play.

:lol:

:lol:

ok, am I the a$$ of this joke?

yes:lol: they have nothing beter to do than:sheephump with ya with that extra hour they found today i say .:nopics:

:lol: Soory man....I was just playin with the bait that was set out there. Didnt know someone was going to bite. :lol:

I was gonna say my buddy use to joke about his "chrome" muffler bearings and how they gave him 10 extra HP on his camero,

U guys suck:mad:

yes:lol: they have nothing beter to do than:sheephump with ya with that extra hour they found ..... .


It's true...:laugh_exp

I was gonna say my buddy use to joke about his "chrome" muffler bearings and how they gave him 10 extra HP on his camero,

U guys suck:mad:

Ya but they had me laughing my ass off!!!!!!!!!!!!

Reference:

Muffler bearings are found on the same page with piston return springs, blue sky hooks, buckets to hold a pound of steam....etc, etc..... now you know.

Reference:

Muffler bearings are found on the same page with piston return springs, blue sky hooks, buckets to hold a pound of steam....etc, etc..... now you know.

Piston return springs do exist!!!! In my old 6.5, they were in the cylinder head and also acted as vlaves! BUt when a piston disconectes from a rod, the valves automatically become piston return springs:lol:

I was going to suggest using the Banks Power Pickle Pulse Converter but you guys probably wouldn't believe me.

Only a madman would put one of those on the family vehicle...:mad:

Power Pickle can be seen at the bottom right hand picture at:
http://www.bankspower.com/Banks_FridayNight_040502.cfm

They don't sell muffler bearings because their exhaust systems use heavy duty clamps and thick flanges from what I've been told.

It's official, folks! I've seen it all:D .

Getting back to my acoustical exhaust system, I just ordered 2 sound dampeners. I'll post results in 2-3 weeks.

yea the sound dampeners thats the doughnuts i was talking about...lol

As promised, here's my update. The dampeners came in today. Sorry, no pics.

The dampeners look and feel like nothing more than short pipe sections capped on both ends and filled with lead pellets...BB's?

I welded them both to an exhaust clamp, crawled out under the 'burb between rain showers and now it's part of the family truckster.

There's a noticeable reduction in interior resonance.:) I still have pretty good drone at about 15-1600 rpm. This may be due in part to a timing issue (poor mileage right now).

The next step that I took was to remove the 5" stainless steel exhaust tip. I found the section of tail pipe that I had cut off when I installed the 5" tip. I shortened the cutoff piece so that it would just reach the inner edge of the stainless tip. Then I created my own glass pack exhaust tip.

Well not really, I stuffed the cavity between the tail pipe and the exhaust tip with ceramic wool insulation. (had it on hand and it's non combustable).

The glass pack tip actually helped. It probably brought the noise level back to where it was before I installed the tip. Only thing missing is the rtv to seal the gap between the tip and the tailpipe.

So those high performance chrome muffler bearings did the trick:lol:. Where did you get your dampners from anyways? I have a drone in mine that match's the harmonics of the driveline at about 61-64 MPH and it gets annoying at times, maybe those would help.

I got them from teamchev.com. Specify that you're making an internet order. It's cheaper. Honestly though, if you have a welder, some steel pipe and some lead pellets, you'll save yourself some money. They are very simple in design.