No cats, Damage?

[ConElite]

My cats are shot and I wont be able to replace them for about 2-4 weeks. I am planning on taking off my Y-pipe to confirm that the cats are gone. I figure If im going to replace my cats and my stockers are toast that I would knock out the Honeycomb Inside and make a Bootleg Off-Road Y-Pipe.


Question: I know its going to effect the A/F ratio, with the PCM going out of wake but will it damage my O2 sensors and/or damage anything at all on my car if I run it like that say for a month.


Im getting about 10MPG thats how bad my cats are clogged so I dont think my MPG can get any worse.

[msfyter]

Can you get your PCM reflashed ? Your O2's will probably need replacing.

[Injuneer]

Removing the cats will not affect the A/F ratio. The A/F is controlled by the pre-cat O2 sensors. The after-cat sensors are just there to make sure the cats are working. You will get an SES light for the missing cats, but is won't affect how the engine runs. You will not damage anything. Just make sure the exhaust system is buttoned up tight, so there are no leaks that can affect the pre-cat sensors.

[ConElite]

Removing the cats will not affect the A/F ratio. The A/F is controlled by the pre-cat O2 sensors. The after-cat sensors are just there to make sure the cats are working. You will get an SES light for the missing cats, but is won't affect how the engine runs. You will not damage anything. Just make sure the exhaust system is buttoned up tight, so there are no leaks that can affect the pre-cat sensors.

Awesome, Thanks a bunch Fred.

Im going to Knock those bad boys out in a bit. Ill post somesound clips. Stupid loud here I come.

[msfyter]

Just be careful, if johnny law stops you and check thats big trouble.

[ConElite]

Just be careful, if johnny law stops you and check thats big trouble.

Oh yeah i know its only going to be for like 2-3 weeks or so.

[Wild Willy]

Yeah, don't want to get in trouble with smog police. If a dealer of shop does that kind of work, it becomes a federal case. Some states don't have smog laws, that is why you see people in these forums running long tubes on the street. Even the people that sell the O2 sensor replacements, that simulate a "okay" reading to the PCM are being prosecuted. Sounds crazy, but in a few years probably won't be able to mod your car at all- at least, not legally

You might notice a little difference- I had one cat empty itself out by itself on a '95 Caprice and all that happened was it was a little louder- not much SOTP feeling that I could notice-

After you price the stock parts at the dealer, you may want to look at some performance free-flowing ones- they will probably be less expensive-

[RAF7789]

Yeah, don't want to get in trouble with smog police. If a dealer of shop does that kind of work, it becomes a federal case. Some states don't have smog laws, that is why you see people in these forums running long tubes on the street. Even the people that sell the O2 sensor replacements, that simulate a "okay" reading to the PCM are being prosecuted. Sounds crazy, but in a few years probably won't be able to mod your car at all- at least, not legally

You might notice a little difference- I had one cat empty itself out by itself on a '95 Caprice and all that happened was it was a little louder- not much SOTP feeling that I could notice-

After you price the stock parts at the dealer, you may want to look at some performance free-flowing ones- they will probably be less expensive-

The only after-market cats i have found are "High-Flow" ones and thereforer "49-state legal" (the 1 state not included is the lovely California ) I have also read that high-flow cats are "illegal" to use on OBDII vehicles in California

[Wild Willy]

Yeah, if it doesn't have that 'magic' CARB number, no good for you- sorry

[ConElite]

Yeah, if it doesn't have that 'magic' CARB number, no good for you- sorry

Even with a carb number here in california Not one single company makes a Legal Cat replacement besides from the dealership..






Well I got to taking off the catts yesterday and knock out the insides, Something that I figured would take about 1-2 hours. Well Lets just say that turned into a 5 hour job thats to 2 Studs snapping off the manifold. It was so rusted that they were locked on there and I took an impact to it and "Snap goes the bolt."

So I drilled both bolts out, Messed up 5 drill bits and finished.

I was looking at the cats and they look fine. They dont look like they are cracked or anything. Can they still be cracked and/or damaged from the middle section or no? They only thing that tips me to thinking its that is bc it still makes that whisle noise when I press the gas hard.

What do you guys think. I Cleaned the O2 sensors while I was there. Used Contact cleaner and a wire wheel.

[Injuneer]

You can't actually see the "sensor" part ("thimble") of the O2 sensor. Its covered by a steel shield, with slots in it. What you did was clean the shield. NEVER a good idea to spray anything on an O2 sensor.

Did you try starting it without the Y-pipe on it? Did it still "whistle"?

[ConElite]

You can't actually see the "sensor" part ("thimble") of the O2 sensor. Its covered by a steel shield, with slots in it. What you did was clean the shield. NEVER a good idea to spray anything on an O2 sensor.

Did you try starting it without the Y-pipe on it? Did it still "whistle"?

I did. I didnt drive it, I reved it but I mean its so Loud You would not be able to hear it anyways.

[Timbers]

hmm

Does running without cats, and installing the cat simulators into your after-cat O2 sensor plugs give you more horsepower?

I wouldn't mind installing an open Y-pipe and running O2 cheaters, if it gave me more horsepower. I think the added loudness would be cool!

How much power would you gain, if any? I'm running Edelbrock headers and Edelbrock cat-back, stock Y-pipe.

...Tim

[ConElite]

Does running without cats, and installing the cat simulators into your after-cat O2 sensor plugs give you more horsepower?

I wouldn't mind installing an open Y-pipe and running O2 cheaters, if it gave me more horsepower. I think the added loudness would be cool!

How much power would you gain, if any? I'm running Edelbrock headers and Edelbrock cat-back, stock Y-pipe.

...Tim

Depending on what state your in, if you can get away with no cats. Here in california if you simply change ur cats its illegal. Relocating them is illegal. Just about everything is illegal here.

With a catback and heahers I would recommend running a custom Y-pipe and some Highflow Cats. Should make a little difference. Well under the 10hp range.

[Christopherrr]

You could...ahem, run a straight pipe through the cat...and wire a o2 emulator. That's of course if you plan to keep off the road...