[FSTDANGO3]

Cat back is absolutely fine, modifying or removing the cat is a not a good thing
Steve
DOC Pres

 

[MWeed]

We're stuck with the laws that are on the books. That's why SEMA has worked so hard to get the laws written for aftermarket parts to be legal for us to modify our systems and still make them run well and legal.

Given, the factory muffler is a waste of metal. It's perfectly legal to do anything that you want to behind the cat, and I say go for it. Just leave the stuff that cleans the exhaust where it belongs, specially since it flows so well. You'll never see the performance gain on the street from our rigs by pulling the cat. If you do, it was bad and needed to be replaced anyway.

 

[BangkokD]

Nobody can say my Durango isn't green, not even the Peoples' Republic of California! :mrgreen:

 

[MWeed]

And it runs really well.

 

[sw1tch_nut]

Basically I just want to remove it so I can run 2 cats on 2 separate banks. I don't like how low the "cross tube" part of the Y pipe sits. It's the lowest part of my truck and I don't want it getting caught on a rock or something when I'm off-roading. If I run the pipes my way, I'll tuck them between the frame rails, then between the body and frame (made possible thanks to the body lift and some slick engineering) and then dump them out right before the rear tires in a downward direction to help keep water out. Air pressure along with exhaust gases will help keep water from back filling into the pipe when I do water crossings.

 

[MWeed]

Just so ya know., I can't think of a D here that off-roads seriously that's had a real problem with the y-pipe on their rig. The y-pipe on the PHP headers sits even lower and I haven't had a problem with it yet.

Again, getting the sensors for the driver's side exhaust to communicate properly with the computer so it can function properly would be a real nightmare.

 

[FSTDANGO3]

Agreed. If you can find a way to make both banks communicate with computer properly it should work. The problem is they need to read catalyst efficiency to determine the proper fuel mixture.
Where are the 02 sensors on the D currently?
Is there one on each exhaust manifold downstream from the cats? And where's the second one or more, most likely after the 3rd cat.
Steve
DOC Pres

 

[sw1tch_nut]

I have no O2 sensor after the third cat, at least none that I can find.

 

[FSTDANGO3]

So are they both before and after the each banks converter?
There has to be upstream and downstream I'm almost sure.
Steve
DOC Pres

 

[tomk]

I forget again what year his rig is.

If it's an '01-'03 (at least), it has either two O2 sensors (one before and one after the main cat) or four (one before and after both mini-cats.)

?tom

 

[FSTDANGO3]

It's an 03 with Cali emissions so there's one sensor before and after each pre cat.
I don't know if you true dual this after the pre cats if it'll throw a code?? If there's nothing to measure the 3rd cat's output, then losing it shouldn't cause anything to happen. Its still illegal, but nothing will happen.
Steve
DOC Pres

 

[tomk]

I agree. If you keep the minicats and the O2 sensors, the PCM should be none the wiser.

But it'd still be good to have a pair of real cats backing up the minicats.

Something in the back of my mind is telling me that a dual exhaust without a crossover has some strange behavior, but I can't remember exactly what. I do recall a couple of those TV hot-rod-customizing shows where they explicitly Siamesed the two sides together for a short stretch with a slot and some fancy welding and that seems like a lot of work to go thru if it doesn't matter.

?tom

 

[MWeed]

For performance you need an x pipe somewhere. It evens out the gas flow from all the cylinders.

 

[BangkokD]

Just so ya know., I can't think of a D here that off-roads seriously that's had a real problem with the y-pipe on their rig. The y-pipe on the PHP headers sits even lower and I haven't had a problem with it yet.

I'm surprised my PPH y-pipe is still attached. It has a lot of gouges from various stuff I've run over, but it's still hanging in there. The noise it makes when scraping across rocks is always worrisome, but so far, so good.

Dave

 

[MWeed]

Same here. I've learned it must be made out of unobtainium or something to hold up like that.

 

[IndyDurango]

unobtainium

:cheesy:

Avatar was a really good movie. :thumbsup:

IndyD

 

[sw1tch_nut]

unobtainium

:cheesy:

Avatar was a really good movie. :thumbsup:

IndyD

that was actually (or at least originally) from "The Core"