Cut exhaust, knock out cats, use band clamps

[cook00explorer]

My X is a 2000 V8 AWD it's sucken' gas like it's owned by the arabs. I'm thinking with 145K on it the cats might be clogged. Seen it before. Anyways, I'm thinking about cutting the pipes behind the cats, knock the cuts out and put it back together with some nice SS band clamos but what size is the pipe?

Any idea? What do you guys think about this idea?

TIA, Matt.

 

[Maniak]

If you just remove the cat (or gut it), besides being illegal, you will throw codes. You have a downstream o2 sensor that checks the efficiency of the cat. If its not there or is gutted it won't be doing its job and you will throw a 420 or similar code.

Since your not in CA so you don't need carb approved Cats. Just grab a Good Universal Cat, cut out the old one and bolt in the new one using Band clamps...

~Mark

 

[SoNic67]

If the cats are clogged you would have loss of top-end power, but the gas mileage won't change since air-fuel ratio is controlled by the pre-cat O2 sensor. Better try to replace those O2 sensors.
Or replace the car, don't expect a 4300lbs V8 5.0L AWD hunk of steel to suck gas like a 2600lbs 4 cyl 1.6L FWD Fiesta.

 

[cook00explorer]

I know it's not good on gas, I don't expect it get 25 mpg in the city but when it's worse than my full size 351W 4x4 EC F-150 somethings up.
Maybe I'm crazy but, I could have sworn the O2s were up stream of the cats. If not, there's MIL eliminators to fix that.

I guess I was just being lazy. I'll go jack the ***** up an measure the pipe OD.

 

[Cranmaro99]

There are O2 sensors before and after the cats. The fronts and the rears measure different things.

 

[SoNic67]

The O2 sensors AFTER the cat are measuring only the efficiency of the cat converter itself. They don't affect anything else.
The ones BEFORE cat will affect the mileage. Butchering the cats and adding "MIL" eliminators not only is illegal (federal) but will do nothing for your gas mileage.

 

[FIND]

Cats CAN last beyond 140k miles or more. Why don't you try figuring out what is actually wrong with your truck before you do a modification that is going to get you a ticket that is much larger than the gas money you would save even if a clogged cat was your problem?

If your cats were clogged, you would be throwing a CEL. At the very least, you should be able to scan your truck and get a P0420, P0430, P0421, and P0431.

One would think one wouldn't want to do something stupid like that in a state where they test emissions... I mean, better to get poor mileage and be able to drive the truck than get the same mileage, but get an annoyingly loud drone from an engine in a vehicle that you can't drive on the road.

 

[buzz]

Use an ifared thermometer to chack cat temps and back pressure test. Thinking they are clogged is not enough evidence justifying a removal and or replacement.

 

[derek_redneck91]

Right now my explorer is using a bit more gas too and it's because of the front two O2 sensors. They are a little slow in responding to the computer asking for information. It takes them a while to respond, and thus your computer can't tell if the engine needs more or less gas so you end up dumping in more fuel than needed. They are 88 bucks a piece or less.

 

[cook00explorer]

Some really good suggestions here guys, I really like the idea of using an infra red thermo. Thanks!

 

[FIND]

Why don't you check your exhaust manifold for cracks or leaks around the gasket area. That would cause you to use significantly more fuel.

 

[Dono]

Find is absolutely right.
I'd even go further to say that you might hurt gas mileage if you eliminate your cats. If you do remove them, you will have to get a tuner and program to get rid of the engine code.

Here's what I did (For what its worth). Because I am using forced induction I had back pressure issues in the exhaust and was popping egr dpfe hoses all the time. So, the exhaust shop put in a high flow muffler, removed the cats and installed a single high flow cat. It would have been very easy for me to just have the cats removed and a tune file modified to not look at the post cat o2 sensors since I have everything in place to do so.

Also, gutting the cats will make your truck noisy as Find said. Cat's do act as mufflers of sorts.

Just my 2 cents.

 

[cook00explorer]

Why don't you check your exhaust manifold for cracks or leaks around the gasket area. That would cause you to use significantly more fuel.

I did that, she looks good. This X has never been in the salt so it looks like new down under.

 

[Steamer170]

I had cat issues quite a few years ago and ended up just gutting them. I have a 01 4.0 SOHC XLT with a magnaflow exhaust. Yes the vehicle is running a little louder but I gotta admit even though its a V6 I do enjoy that rumble.

 

[SoNic67]

Resurrecting a tread from 2012 to tell us that you like the louder rumble???

PS: Maybe your neighbors or drivers around you think differently...