[IndyDurango]

My '99 Durango 5.9 was very quiet. I wish I could remember how the exhaust was configured and if it had a muffler and resonators.

No resonators on the Gen1s.

Exhaust manifold/headers-->Y Crossover-->Pipe-->Cat-->Pipe-->Muffler-->Pipe-->Tip

Resonators are 'new' to the Gen2s. I hate seeing them from behind while driving. When I had my hitch on there, I couldn't see my Spare Tire and liked that. Now that the hitch is off, I can see the spare and I'm working on a solution (for the DOC Smokey Mountain Rendezvous)

IndyDurango

Again, here's all you need/should have:
Exhaust manifold/headers-->Y Crossover-->Pipe-->Cat-->Pipe-->Muffler-->Pipe-->Tip

With the looks of that setup and condition (surface rusts) and you're already having sound issues, I'd scrap it and get a full replacement under there that follows this path:

Exhaust manifold/headers-->Y Crossover-->Pipe-->Cat-->Pipe-->Muffler-->Pipe-->Tip

Most shops can fab one up plus Flowmaster, etc have the complete setups.

IndyD

 

[FSTDANGO3]

You have a CA emissions Model D with the extra Cats off the manifolds
As Indy Stated I'd get Headers as well to a new Y pipe to One Cat then a Nice Cat back exhaust.
I wonder if the Drone is Due to all the restriction in that system
Steve
DOC Pres

 

[GreenD]

So the two small cats are for CA emissions? That would explain this odd setup.

Sounds like I finally have a plan, and I'll include a set of headers. I'm leaning toward the Flowmaster Series 50 SUV after more online research, though I'm going to look and read a bit more before deciding. I'll speak to a local performance shop tomorrow. I'm hoping the one larger cat is still usable to keep the cost down, unless you guys think its a mistake to use it. I only have 40,000 miles on it so I'd think there's plenty of life left.

The 2 sensors and leads to the small cats - what needs to be done with these? I don't know if they can be just disconnected or not.

Thanks for all the help with this, I'll keep you posted on progress.

 

[TheDodgeGuy]

Believe it or not, the diameter of the tip makes a difference. I know this firsthand from the Grand Cherokees. In '98, the 4.0L I-6 got the V8 tailpipes with their 3" tip, and were noticeably louder than previous years with a straight 2 1/4" pipe.

I did notice that the 5.9L SLT+ I drove had a little more "bark" than my 4.7 does. Dodge seems to not be all that bashful about the sound of their engines. Even my dad's new Ram has quite a powerful sounding exhaust note. Compared to the F150 we looked at that had a bigger engine, it was whisper quiet by comparison.

 

[MWeed]

I don't know your location, but if it's CA, you can't just eliminate cats as you want. You won't pass the visual inspection when they smog your D the next time. Cats should last a lot more than 40k, unless yoiu have either a major oil consumption problem or are running way rich.

That being said, your system looks to have been bathing in salt air for some time, like it was at the beach a lot. The pipes are in poor shape for only that amount of mileage. Same thing with the muffler and cats. Just replacing everything is one way to fix it, however I'd start after the cats first, replacing pipe and muffler. The front half, the cats, I'd do only afterwards, as cats can get expensive to replace. There's an extended warranty for cats that's separate from the drivline warranty and they're covered under an emmissions warranty that specifies mileage and time for them to be covered by the factory. If the problem still exists after the mufflers, I'd look into that angle for the cats, first, before paying for them yourself.

 

[GreenD]

I'm in New Hampshire (I guess I need to add that to my signature.) The rust is from road salt, hard to avoid it around here. So, no CA smog police to get past.

You're advice is good, I'll see what the shop says about the old cat. I'll get a quote both ways, but I'd be inclined to replace the whole thing while I'm at it. Even a good flowing cat adds restriction, and having 3 of them has to have quite an effect on the engine breathing.

 

[IndyDurango]

GreenD, if you're wanting headers, get in on the group buy we have going. They (the headers) are excellent.

http://www.durangoclub.com/forum/viewtopic.php?t=6120

IndyDurango

 

[FSTDANGO3]

I concur

I believe it'll be in your best interest to look into it with a shop also As Indy Stated the opportunity is there soon for the headers and they're the best.
Steve
DOC Pres

 

[GreenD]

In reading the older group buy thread, the pre-cats in the Y-pipe issue is discussed. Here was a comment from Fastman:

If you have precats and remove them to fit the new Y pipe you'll trip the CEL. (Check Engine Light)
It'll also cause poor and erratic idle. To put out the CEL and correct the problem, you'll need my Simm boxes. One for each precat so you'll need the Dual Simms. They're sold for Offroad Purposes Only.
Another hidden cost you should be aware of for those with precats.

Fastman
www.thefastman.com

So, as usual, just do a bit more reading here and problems are solved. After I talk to the shop (or a few?) I'll decide whether to join the group buy.

 

[FSTDANGO3]

ARGH

Damn Cally Emissions!!
Keep us posted on your progress
Steve
DOC Pres

 

[TheDodgeGuy]

Feel free to call me ignorant, or anything else, but wasn't this thread about getting his D quieter on the highway? If so, why are headers and high-flow exhaust systems being discussed??!?

 

[GreenD]

Mike, the more I read and learn the more I think the stock R/T exhaust I have is causing the cabin noise (resonance?.) So, putting a flowmaster SUV 50 muffler on seems like it'd improve my noise level on the highway. I hope I'm not missing the point here.

The headers shouldn't be any louder than manifolds (am I right?.) So, while I'm at it, seems like getting rid of the 2 pre-cats, adding headers and a new fairly quiet exhaust will get me a good compromise, lower noise and resonance and better flow and power.

If you think I'm heading in the wrong direction let me know, I'm relying very much on DOC opinions here. I don't mind spending the money on this project, but don't want to end up with a louder D!

 

[skitzo.d]

I ended up with a louder exhaust when I added my headers, but only when I open it at WOT?

 

[dizzyD]

Agree with headers WOT it's louder, all other driving with stock, yes stock, muffler is quieter.
5.9 non RT

 

[Volphin]

Not louder.

My headers didn't add any noise in the cabin. They're still running to a stock muffler? for now. I like surprising the teenage hot rodders.

Mine is a single cat system.

Bill

 

[TheDodgeGuy]

Re: Not louder.

I like surprising the teenage hot rodders.

Me too! A while back, I dusted a little riced out Hon-duh Civic from the stoplight, and when he tried the famous "ricer fly-by", I waited till he got up close to me, then stood on it again, and pulled on him by a couple carlengths.

The whole time I'm thinking to myself, I wonder what's going thru that guy's head right now?All the wasted money on air intakes, big dopey exhaust pipes, and hideous body kits, and he gets absolutely annihilated by a stock SUV that weighs two and a half tons! :mrgreen:

Oh well?He was most likely getting better gas mileage as I was beating the socks off him! :mrgreen:

 

[FSTDANGO3]

Must be that he's not using shaeffer oil and Champion Plugs! LOL J/K

Steve
DOC Pres

 

[Grease is the Word]

After a little while with the Magnaflow 24" muffler, my wife made the comment that it was barely ouder than stock. I'm very happy with the performance and sound. If you're going to swap mufflers, check out the MF. Plus the stock MF is SS.

 

[TheDodgeGuy]

Must be that he's not using shaeffer oil and Champion Plugs! LOL J/K

Steve
DOC Pres

 

[FSTDANGO3]

Must be that he's not using shaeffer oil and Champion Plugs! LOL J/K

Steve
DOC Pres

Better the Dead Horse than YOU! Peace!
Steve
DOC Pres