I have also posted this in the exhuast form but think you guys have more experience with 2.8 exhuast. I notice my exhuast on my car is pretty loud for a stock exhuast. It seems tho when i start off or put pressure on the motor it is louder in the front. I have already replaced the exhuast manifold gaskets along with Y pipe dounuts (not the cheap serramic ones) and I have a whole new exhuast cat back. I was wondering if my cat is bad, not sure if its the orignal one or not, but sounds loud by the cat and in front of the cat where the Y pipe goes up? Could the cat be no good and cause the exhuast to be very loud in the Y pipe? I also put my hand down by the Y pipe and felt around the dounut, doesn't seem to be leaking and revved the motor up with my hand there. Any ideas? How can i tell if my cat is bad? Should I take it off? Thanks guys

 

If the cat was/is bad, your exhaust would smell like rotten eggs.
Or it would rattle if you hit it with a broomstck or something.

 

Smells a bit rich, and does rattle if i hit it. I decided to take it off tonight, but which CAT do i get to replace it, the direct fit for 93.00 or the universal for 65.00. What do you think would be better? I noticed that now my Y pipe moves alot up and down, is that normal or is that a problem, could that habe been why its loud? Thanks man

 

I dunno where you're shopping at but I got a direct fit cat (wasn't direct fit due to some a$$hole's incompetence) at AutoZone for $65. They have a website you can order from if you don't have a store locally. Don't forget sealer while you are there!

PS.: If the y-pipe moves at all it is still too loose!

 

Wow thats a good deal. What is sealer? Yeah the Y pipe is moving, does that mean the dounut gaskets arn't sealing? It sounded like it was leaking when i put pressure on it, and the Y pipe always hung real low, is that normal? Is that sealer suppose to go on the dounuts also? Thanks

 

1. Yes, it is a good deal.
2. Sealer is just what it says: exhaust joint sealer.
3. YES!!!
4. The y-pipe should remain in the normal position when the cat is removed. The normal position is the position in which it is placed when all of the joints are properly seated and the flange of the cat is connected to the trans hanger (if you don't have one, its GM part # 10026086 and is $23). When correctly installed, (roughly) the lower half of the y-pipe should be visible below the lower edge of the chassis when viewed from the side.
5. NO!!! The donuts are supposed to be doing the sealing.

On my 2.8, I could easily move the y-pipe around after I had cut the test-pipe (the blasted thing I had to cut off to put the cat on) off, and I knew I had a good size leak in the front end. I could tell because I could always hear engine noise when going down the road next to a guard rail or building. If you can hear any engine noise while driving at a good speed, and it gets louder when you are close to another vehicle or guard rail, and you can tell it is coming from either the pass side or the front end, the donuts are not seated right. Also, you may want to change the O2 sensor when down there if you haven't done it yet. Look for carbon trails on the manifolds to see for certain if you have a leak, because if there exists a carbon trail, the donuts aren't sealing.

 

I used green dounuts, they were made out of like stuff they make corks out of. I thought i had them tight, could they have loosened from me working the cat off? Cuz that cat was not easy to get off. Where do i buy the sealer and where does it go? Thanks

 

Is your exhuast nice and quiet even when applying pressure to the motor at lower rpm? Is it loud on the passenger side at all? I can here exhuast more when i apply pressure, does that mean bad seal, because it smooths out at high rpm. Thanks again

 

I wouldn't know. My engine has not run right since last October, and not at all since February. Luckily I get a 3.1 to replace it next month (number 4 connecting rod blew apart and now theres a hole in the oil pan and block.. ) so I'll get to find out.

I have a Flowmaster anyways so it can be hard to tell. However, since I had to make an adjustment to my new cat, it has three to four leaks, one at each joint (3 joints... front, adaptor to cat, and adaptor to cat-back) and one in the middle of the cat that I'm going to have welded shut when I get my 3.1 installed. If you're confused, I'll get a pic of what I mean. I had to buy a 2" OD to 2.5" OD adaptor to fit the cat properly because the moron who installed the test pipe cut the cat flange off in the process.

 

Yeah, Thats cool though. Hows that flowmaster sound, interested in that for mine, but i couldn't anyone who had it on their car. You got the Y pipe dounuts seated good though? Why was the cat leaking? That seems strange. what do you do with the sealer? Thanks for all the help

 

You have aol messenger or something, instead of posting. May go a bit faster

 

You won't like it. It sounds okay when you are revving the engine but at highway speeds it gets really annoying.

I'm going to have to replace the donuts again along with my O2 sensor (that thing is as black as black ink!). The sealer is supposed to go on the joints between the cat and y-pipe (never on flange joints!) after the two pipes are seated. However, I have used the sealer this way half a dozen times, and even letting it cure for 24 hours (when the engine actually ran) it still leaked when running the engine. I'd put the sealer on rather thickly to the y-pipe before assembling the joint and seeing what happens. I'll have to do this when I get the car back...

 

AOL: same username, all one word, all lowercase.

 

A bad cat does NOT always smell.

My bet is your Y pipe is cracked where it Y's in.

 

I have been chasing the loud exhaust sound too.

My pipes all looks great, except in the bends. The extra heat banging against the pipe walls as it forced to turn is super rusty.
I found one that that just blown through with lots of little not so easy to see holes.

It was either fix it or whole new cat back.

So I got out the welder. Managed to welded a good strip of metal over most of it. Moving fast n quick as it burnt through easy. With most of it covered I grabbed some quick JB weld. [ reg is too sloppy and takes to long to set] That covered it up well and sealed all the tiny holes.

Worked really good but it was still loud. And everything looked OK else where. Today changing the oil I realized the pipe that replaced my cat was free and lose. The exhaust clamp had rusted about
%40 away but look fine from a few inches. But the whole pipe was able to slide back n fourth.

More quick jb weld. I like using it anyways when pipes slip fit. They will never leak or come lose after that.

Well you know it still sounds like I have cut outs open. As I did my heater core bypass. I checked my exhaust gaskets ad donuts at the headers and they were tight n good.

[ I will check for that crack in the Y pipe. ]

But I know suspect its the donut or clamp where the pipes come together before the cat. That funky union clamp.



So check all the bends real good in the pipes.
grab the exhaust n shake it around n grab each pipe clamp and see if it holding tight. It may be rusted through n just appear to be working like mine.


OT: I also fixed my retarted hatch pull down with my welder. closes tighter than it ever did. I love my welder.

 

Well OK I found the mystery exhaust leak. Might wanna check this one out your self as its a tricky one that is almost impossible to see until you un bolt things.

The flange clamp near the cat position was sealed fine and tight. Ahhh but a reach around the pipe while running revealed leaking exhaust. The clamp it self was / is fine but inside the lip the pipe had blown away.

 

I just cut the sucker off and replace it and the flange clamp with a piece of straight pipe.

 

glad you got it fixed, i to am having a leak but its an exhaust manifold leak, i had time to check real good and found out i have 2 bolts missing , think its time to replace those rusty manifolds with some pf&e headers

 

Well I am still unhappy. Now its too dam quiet and feels a tad bit restricted. So its gonna get a free flowing glass pack. Loud is ok but not right under my seat.

 

do what I did

 

Yeha i put a CAT on but i can here it leaking, either at the spot where the y pipe connects to the cat or where the y pipe connects to the manifold on the drivers side, it one or the other. Any suggestions, anyone knwo how far the why pipe shoudl go into the cat? Thanks

P.S. I would fail emissions without a cat, no option.

 

Well After fixing all my exhaust leaks the car felt a tad restricted and super quiet. I almost went with a gutted muffler as a cat back would cost to much and I already replaced most of those pipes. So I had to think.
<P>
Biggest issue is the dam dual exhaust tips. How do I keep the dual without a plumbing nightmare. Less plumbing is better for flow. So I bit the bullet and went for a single out let.
<P>
But instead of going out the back. I went out the side. Looks real nice n clean. Sound fricking neat.
<P>
I welded everything and then sealed any pin holes with JBweld. Going for my first drive in 5 mins or so. Gotta make sure the JB weld cures for a min or two so it don't come off.
<P>
Before
<BR><IMG SRC="http://www.viragotech.com/86bird/exhaust/CAR1.JPG" HEIGHT=480 WIDTH=640>
<P>After
<BR><IMG SRC="http://www.viragotech.com/86bird/exhaust/1010091.jpg" HEIGHT=480 WIDTH=640>
<P><IMG SRC="http://www.viragotech.com/86bird/exhaust/1010092.jpg" HEIGHT=480 WIDTH=640>
<BR>Those are cool tips. They have open back so the tips doesn't get to
hot and melt body work.
<P><IMG SRC="http://www.viragotech.com/86bird/exhaust/1010087.jpg" HEIGHT=480 WIDTH=640>
<P><IMG SRC="http://www.viragotech.com/86bird/exhaust/1010088.jpg" HEIGHT=480 WIDTH=640>
<P><IMG SRC="http://www.viragotech.com/86bird/exhaust/1010090.jpg" HEIGHT=480 WIDTH=640>
<BR>&nbsp;

 

Oh yea baby.

They say its impossible but you can make a V6 sound like an 8.

I didn't rev pat 5000RPM but it kept its deep throaty sound all the way up. The winy 6 sound never came through. Even the down shift sounds cool. Car could easily pass for a 8 with its sound.

Its frickin neat.

 

Sorry for hijacking your thread.

I found my last two hard to find leak by feel. I felt around the pipes as the car ran. And felt where it was leaking as the sound trick didn't pin point them.

 

It alright. WHat did you run for that muffler there? Mine is still loud

 

OOps, that is a $17.99 Cherry Bomb form the grocery store if you can believe that. No one carries them anymore but Myers did.

I was gonna go Thrush but $26.99 for glass pack is to much in my book. CB use to be $9.99 everywhere. I now have them on both my Buick wagon and Firebird. Sounds great on both.

 

Ill post here just to compare.

Turns out more hidden leaks. From one green line to the other, the top of the pipe was rusted out. Where the rest / bottom of it looked fine. So you really couldn't see anything wrong but the car was much louder. After I cut everything out, I found out what was good or bad. So I had to change the muffler design.

Chopped the end of the Y pipe off as it was angled under the car stock. [Found it strange that the Y pipe is made from double wall tube. Though you can't tell till cut open.]

There is just so little room under the car all I could do is use the side body seam to tuck everything kindof into. There was no room for a real turn out pipe. So I cut the dual tip I used above off at a point where it fit onto the pipe well. Made like my own Lakewood side pipe. Fit everything so it would flow well. Wish I would of gotten some pics. Someone ran off with the digi cam.


So the pipe now exits on the right just in front of the tire. Sound is good but very different. I'm use to it on the other side.

 

Ignore my nasty door. It needs replaced but I painted it anyways with the rest of the car.

Sounds good, looks neat, makes it more road warrior like with everything black.

 

you know door handels are easy to replace and also easy to find
:-p

 

Yea I know. Im lazy at some things.
Plus I never see that side of the car.
Though I need to just change the doors. Both are shot.

 

That is some ghetto fabulous engineering there