Hi, everyone and happy new year. We have a 2003 durango with the 4.7Land was thinking about headers and if it was possible to gut or remove the cat completely without affecting performance or gas mpg(more would be great,less would be terrible). Does anybody know if this is can be done? I don't know much about cats or what their purpose is. So any info would be helpful.

Thanks everybody.

 

You could just gut it and keep the O2 in place, but make sure that all the honeycomb substance in the converter is out. I can't say this won't trigger the O2 to go off, but if it does, it will turn the check engine light on and more than likely effect your MPG.

 

Chillin:

So far, I have not seen any headers advertised for the 4.7. The factory cat on your D actually flows pretty well. You will not gain much if anything by gutting or removing it unless you are going to seriously crank up the HP on the motor.

MPG on a Durango sadly pretty much is what it is. 4800 pounds with the aerodynamics of a brick equals what we get which is usually 12-14 in town, and 16-19 hwy. My experience has been that the 13/18 rating on the window sticker is pretty accurate.

Don

 

Hi n8ech,
The reason I was thinking about removing or gutting the cat is for 2 reasons. 1st: we were having problems with one of the 02 sensors(one of four,if you can believe it has that many.I still can't)but anyway our mpg dropped to the point it was cheaper to drive our ram which averages about 10.5 mpg. I read somewhere that if you ignore the problem, it could damage the cat. I think this is the case, because we did drive it for some time before we were able to narrow down the problem. The only price I could find online for new catwas from a dealer(Around $450-600).

Also before this happened, it developed a exhaust leak. Somewhere from what I can tell around the manafold and cat. I have been under it and can't see anywhere it would be leaking from. So ya all this leads me to believe that thecat is damaged.


So thats it in a nut shell.
Please tell me what you think.

Thanks again

Tom

 

I've read the manifold bolts are notorious for breaking and causing leaks. Start there.

 

I have an 03 Durango R/T and I cannotfind a cat back system. I am told the one that came with R/T package out performs most aftermarket.

 

The rear o2 sensor has nothing to do with your mpg. It only tells the computer if the cat is doing it's job or not which is why if you remove/gut your cat, you will get a CEL.

 

Chillin:

While it is true that driving with a bad sensor can affect your MPG, it is unlikely that your cat is damaged unless you were driving with an engine miss which would dump raw fuel into the cat.

BTW, the reason for the 4 02 sensors is to allow the OBD II system to know if the cats are working as well as to adjust for correct air/fuel mixture. The upstream pair are for mixture, anf the downstream pair tell if the cats are doing their thing.

How many miles on your rig??? Your cats should have an 8 year 80k warranty on them from DC. if you are within these specs.I would be off to the dealer.

If you truly need a replacement cat, a low mileage unit from abone yard or a new aftermarket one should do the trick for $150-300 bucks.

Don

 

n8ech,

Our rig has almost 90,000. Its doing a little better on gas since we have replaced the o2 on the drivers side before the cat. Can't get to the other without dropping the exhaust as far as I can see or modifying one of my wrenches.

I'm going to do a full tuneup as soon as we have the money for it. Ours has those seperate ignition coils for each cylinder. Do you or anybody know if these just lift or twist out after removing the top nut?

But anyway, thanksto you and everybody else for theinfo on the o2's and cat.Makes alot more sense to me now.

Thanks Again

 

Chillin:

Yes, the plug coils come out fairly easily. Remove the 1 nut on the top, and also disconnect the harness plug to allow greater movement.

Then, gently rock abit from side to side while pulling up. They should come off with very little effort.

Re your plugs.If your rig is at 90k, you may be long overdue for plugs as the OEM Champions are only good for 30k. You might consider going back in with the platinum equivalent which is RC12PYP IIRC. I have a set of those in w/ almost 40k, and they still look like new.
Do remember to do the plug swap with a cold engine as the aluminum heads are easy to damage when hot.

Don