Foo - What to look for in a bad exhaust system?

The previous owner of my car said that he thinks the exhaust system will need to be replaced within a year. I already ordered headers to replace the exhaust manifold that was there (which I will admit, looks in awful condition). I took a peek under the car though, just to look for anything awful looking with my exhaust pipes. I didn't see anything awful looking (to the untrained eye). Then again, I didn't really crawl under there either. It passed inspection without any difficulty. Not sure if NH does emission tests or not, but he didn't say anything was wrong and my car's exhaust doesn't smell at all, so I assume my catalytic converter is working well.

I was going to get the car up on jack stands to change the oil anyways, so I figured I would take a look at the exhaust system. What is it that I am supposed to be looking for, to warrant it's replacement?

Cracks, soot trails at the joints, thin spots in the pipewall, Corrosion and rust areas mid pipe indicating pinhole leakage, Bad hangers, hanging pipes......

Can you explain what you mean by "bad hangers" and "hanging pipes". I saw that the exhaust system is suspended by thick rubber, is this what you mean?

Can you explain what you mean by "bad hangers" and "hanging pipes". I saw that the exhaust system is suspended by thick rubber, is this what you mean?

Exactly! Hanging pipes is a sagging exhaust from bad hangers breaking.;)

Are all exhausts mounted the same way? With rubber hangers that is. Those rubber hangers must have been 5/8" thick.
And why are some exhausts considered brand specific? Seems like the only thing that separates a "honda exhaust" from a "toyota exhaust" might be the placement of the hooks for hangers. THat said, if I have to replace my exhaust system after all, do I need to look for one that flat out says "for 1993 honda"?

Are all exhausts mounted the same way? With rubber hangers that is. Those rubber hangers must have been 5/8" thick.
And why are some exhausts considered brand specific? Seems like the only thing that separates a "honda exhaust" from a "toyota exhaust" might be the placement of the hooks for hangers. THat said, if I have to replace my exhaust system after all, do I need to look for one that flat out says "for 1993 honda"?

Hanger placement, tubing routing relative to subframe and crossbracing. Actually, your cheapest route will be to go to whatever the local "Budget Muffler Shop" is and have them install it. The Muffler and tubes are pretty generic, and can be custom bent by a muffler shop cheaper than OEM parts.

EDIT: Often the clamp bolts are so corroded, they need to be cut off with a torch, so that's an issue you need to think about.....safety of using a cutting torch under your car without catching it on fire!

In the future, is it okay to use stainless steel hardware for the muffler assembly? Just to avoid rusting. It never made sense to me why manufacturers don't go stainless with that.
I was actually going to get an aftermarket cat back setup, something with a deeper, throatier sound. It's more fun that way :).

It sounds like I could just ask the machine shop I used to work at to make bend stainless steel piping for me and that pretty much takes care of the piping needs. They have a bender, and I just convinced the company I currently work at to give them quite a bit of business, so I don't think they'd mind.

On a side note (sort of), what is it with an exhaust system that dictates the end sound?

http://www.northernthunder.com/bigtip.jpg

http://www.northernthunder.com/bigtip.jpg

Exactly! Pipe Diameter and type of baffling in the muffler.

Abarth exhaust rules.

Well I crawled under there. Let me first say, it is a real pain in the ass to get underneath this car. I can try and jack it up, but then there isn't any room for jack stands. I eventually gave up and used a ramp.

Anyways, the muffler itself looks pretty good. All of the bolts which hold it together are stainless steel (thanks to the previous owner!). But the pipes are pretty well rusted on the bottom half. I tapped them and flakes of rust came off...
The catalytic converter looked to be alright. It was rusted, but I think it's just surface rust, as no flakes came off when I tapped it. Then there was a piece before the catalytic converter, toward the engine. It looked like it's a steel spring with mesh around it. The mesh was completely rusted away.

The rust concerns me. But, the inspection mechanic didn't say anything about it. He gave my dad a hard time about the exhaust on his Jetta, and made him come back two times until it was good enough. So maybe it's alright after all.

As long as you don't see ant soot trails from the joints, it sounds like you'll be OK for a while. I wouldn't sweat it just yet, PC.;)
Well I crawled under there. Let me first say, it is a real pain in the ass to get underneath this car. I can try and jack it up, but then there isn't any room for jack stands. I eventually gave up and used a ramp.

Anyways, the muffler itself looks pretty good. All of the bolts which hold it together are stainless steel (thanks to the previous owner!). But the pipes are pretty well rusted on the bottom half. I tapped them and flakes of rust came off...
The catalytic converter looked to be alright. It was rusted, but I think it's just surface rust, as no flakes came off when I tapped it. Then there was a piece before the catalytic converter, toward the engine. It looked like it's a steel spring with mesh around it. The mesh was completely rusted away.

The rust concerns me. But, the inspection mechanic didn't say anything about it. He gave my dad a hard time about the exhaust on his Jetta, and made him come back two times until it was good enough. So maybe it's alright after all.

What to look for ... hmmmm.

Look for the commuter on the bike following you wearing a pair of noseplugs. ;)

I guess your right. THe inspector didn't say anything about it, it must be doing alright. When this thing does go though, I'll definitely be going with a stainless setup.

Well, for starters, if the exhaust fumes don't come out of the tailpipe, that's usually a bad sign....

I guess your right. THe inspector didn't say anything about it, it must be doing alright. When this thing does go though, I'll definitely be going with a stainless setup.

I'm not sure you really need to think about that much investment, PC. This is an older car and likely, you're only gong to own it 2-4 years at the outside....

I found that a cordless Dremel with a fiberglas cut-off wheel makes a suitable replacement for a cutting torch when cutting the hangers open.

Keep in mind thet the open end of the muffler hanger points towards the rear bumper of the car...yes it's harder to install in that direction, but it will keep your muffler from dropping if you hit anything against it while driving. Having it drop usually means part of your exhaust pipe will rest on a rear brake line, which means really bad things later on.

I had a critical brake failure during my move to Cali from that exact situation....I discovered this while going 75mph (now sideways) on a snowy decline....with no guardrail on the corner that was rapidly approaching. I'm thankful of all the times I drove like an idiot in snow/ice covered lots since I knew exactly what to do to get out of it, and the car was capable of doing what I needed it to so that I didn't break into a full spin.

Check your muffler bearings and make sure the flux capacitor isn't shot.

Completely forgot about muffler bearings. Good Point WTP! If they are shot, replace them with chrome ones. Chrome adds 10% more power than standard muffler bearings.

Check your muffler bearings and make sure the flux capacitor isn't shot.


...and the henway.

...and the henway.

Do you use a dickfor to check your henway?

Easiest fix is a couple of mufflers mounted directly on the headers. ;)

Easiest fix is a couple of mufflers mounted directly on the headers. ;)

I think it is a inline 4!:D I just cut his work and budget in half.

Easiest fix is a couple of mufflers mounted directly on the headers. ;)

Or just run dumps...

Yea, I replaced my muffler bearings with ceramic ones to get a 5% increase in output power.

If its not leaking too bad and if it just passed inspection, I wouldn't even touch the muffler on a car this old...

Mufflers really aren't a place to look for performance anyway. The catalytic is about 15-20x more restrictive than the muffler anyway. I've seen dyno-tests where an aftermarket cat-back system (muffler) actually gave less power than stock. Don't forget that on NA engines, a certain amount of backpressure is a necessity in order to get mid-range torque & power. It's no fun driving a street car that needs to be revved between 7000-9000rpms all the time to be usable.

For a fast street car, you really want a wide and flat torque-curve for fastest acceleration. Peak power figures are just the result of high-torque at high-RPMs. On a street car, a tri-Y header typically restores the great mid-range that gets lost with 4v heads and aggressive cams.

In the future, is it okay to use stainless steel hardware for the muffler assembly? Just to avoid rusting. It never made sense to me why manufacturers don't go stainless with that.
I was actually going to get an aftermarket cat back setup, something with a deeper, throatier sound. It's more fun that way :).

It sounds like I could just ask the machine shop I used to work at to make bend stainless steel piping for me and that pretty much takes care of the piping needs. They have a bender, and I just convinced the company I currently work at to give them quite a bit of business, so I don't think they'd mind.

why don't all bikes roll off the line with DA or record components? it's a cost to consumer issue. if you wanna spend the bucks go stainless. it's worth it if ya don't wanna mess with it ever again.

TS mentioned tone being dictacted by these factors: Pipe Diameter and type of baffling in the muffler.

don't forget the engine. a high strung modded 4 sounds different than a "typical" factory 4 banger and a V6 or V8 the same way. for that matter, firing order makes a difference too... but yeah, basically you can tune some aftermarket exhaust sytems if ya wanna throw down the bucks. i'd rather spend the money on the engine/driveline work and let the engine sound the way it wants to, but then your inspection folks might not like that.

or move to S.C. they don't give a sh1t what you drive around here... i dont even think you need a license or insurance. sadly... :eek: