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Discussion Starter · #1 · (Edited)
My cat failed on my '98 V70R, so I had it gutted today. It had actually melted parts of the core. The guy that did it for me said he never saw such a badly failed cat before. What are the chances of not throwing a code as it is? I'm thinking 0, but the shop that did it for me said they think it will be fine after possibly resetting fault codes a few times. I was going to space it out with a pair of spark plug anti-foulers. Suggestions? Thanks in advance for any help.
 

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Discussion Starter · #3 ·
Put a new cat on it, aftermarket ones are not expensive
From everything I have read, and several very experienced techs I've spoken to, they also don't last very long and then I would be back in the same boat.
 

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Space it.
 

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If you use a spacer on the rear o2 sensor you shouldn't get a code, although I have heard that it isn't always 100%, so your results may vary.

I just got done doing this on my 1998 VR. I have a custom downpipe and EST axle back, inbetween is straight-piped. No cat. I used this 90 deg o2 spacer and placed it as far towards the rear as the wire length would allow. I've driven it for 2 weeks like this now and no CEL. Hope this helps!

 

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Discussion Starter · #6 ·
Thanks everyone, I'll space it today.
 

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What mileage. In the past I've had a cat fail with over 200k, tuned and beaten daily, miss the poor thing (my fault). Check for either too rich or oil consumption. Let's just say no worries on mine with my Hilton tune in PA as well.
 

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Discussion Starter · #8 · (Edited)
What mileage. In the past I've had a cat fail with over 200k, tuned and beaten daily, miss the poor thing (my fault). Check for either too rich or oil consumption. Let's just say no worries on mine with my Hilton tune in PA as well.
It has 118,000. I've had zero oil consumption so far. It's had Mobil 1 every 5,000 from new. The tune seems good. What I noticed was the cat got an annoying rattle at idle that was really pissing me off. It would mostly go away in neutral, but sounded like hell when in gear idling. I can't stand rattles or squeaks in my cars. The guy that gutted it said there were actually loose broken pieces of the honeycomb structure loose inside when he opened it up. I saw the core pieces, they actually looked really clean, no oil or carbon build up. It still felt good low and mid, but I can definitely feel a difference with the top end. He couldn't believe it when I told him it was a '98. I've owned it since new and it's never been salted, always garage kept, and for the most part I take my truck if it's raining so the car is like brand new underneath. I still love this car. I put the spacers on the rear O2 sensor today, hopefully it keeps it from getting cel's.

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From what I've heard, the spacers work. My cousin has the OBX exhaust on his '99 T5, and it threw codes for the cat. He is NOT running a spacer on his rear O2. In fact, I think he ended up cutting the sensor wiring all together since the fitment of the OBX is universal and newer P80s have the rear O2S closer to the front, so that would explain the codes!

Anyway, as for the gutted cat... it's up to you how you like it as it is, but in my experience the gutted cat makes an awful noise and kills torque. That was with my Miata at least, I replaced that with a Magnaflow high flow cat and the car felt and sounded WAY better. A regular pipe to replace the cat housing would be a much better option.
What I would do is get a downpipe without the cat, and use the O2S spacer. I'm not sure who makes P80 AWD downpipes, though. It would likely need to be custom.
 

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Discussion Starter · #10 · (Edited)
From what I've heard, the spacers work. My cousin has the OBX exhaust on his '99 T5, and it threw codes for the cat. He is NOT running a spacer on his rear O2. In fact, I think he ended up cutting the sensor wiring all together since the fitment of the OBX is universal and newer P80s have the rear O2S closer to the front, so that would explain the codes!

Anyway, as for the gutted cat... it's up to you how you like it as it is, but in my experience the gutted cat makes an awful noise and kills torque. That was with my Miata at least, I replaced that with a Magnaflow high flow cat and the car felt and sounded WAY better. A regular pipe to replace the cat housing would be a much better option.
What I would do is get a downpipe without the cat, and use the O2S spacer. I'm not sure who makes P80 AWD downpipes, though. It would likely need to be custom.
I have only driven it home from the shop so far, about 10 miles. I'm very surprised that there was almost no difference in sound with it gutted. My exhaust is stock other than the cat . I expected a big difference, but it really isn't noticeable. Time will tell about how I like the drive-ability now. It felt great on the way home, but it was only 10 miles. In PA we have state inspections that will not allow just putting a pipe on in place of the cat. It would never pass. it has to look like an intact emissions system and not have any current or pending codes
 

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I have only driven it home from the shop so far, about 10 miles. I'm very surprised that there was almost no difference in sound with it gutted. My exhaust is stock other than the cat . I expected a big difference, but it really isn't noticeable. Time will tell about how I like the drive-ability now. It felt great on the way home, but it was only 10 miles. In PA we have state inspections that will not allow just putting a pipe on in place of the cat. It would never pass. it has to look like an intact emissions system and not have any current or pending codes
Ah, gotcha. I've heard PA emissions inspections are kind of strict. Here in NC they're supposed to check for a cat, but they usually don't bother. As long as there are no codes, you're good to go.
That's a good sign then that the sound is unchanged, hopefully you won't have any performance or fuel economy loss!
 

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No emission stickers in Allentown. Just regular inspection, right?
No one actually checks or reports for a removed CAT. If you're worried, find a local indy you get along with and he should look the other way.
As long as it has no codes, you will be fine, just buy and install a spacer. I did on my wife's R and no more CAT efficiency codes.
 

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No emission stickers in Allentown. Just regular inspection, right?
No one actually checks or reports for a removed CAT. If you're worried, find a local indy you get along with and he should look the other way.
As long as it has no codes, you will be fine, just buy and install a spacer. I did on my wife's R and no more CAT efficiency codes.
Yeah, that's what we do here too. I mean, so I've heard...
 

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Discussion Starter · #15 · (Edited)
No emission stickers in Allentown. Just regular inspection, right?
No one actually checks or reports for a removed CAT. If you're worried, find a local indy you get along with and he should look the other way.
As long as it has no codes, you will be fine, just buy and install a spacer. I did on my wife's R and no more CAT efficiency codes.
We have to have emissions here, it goes by county. If I lived slightly north I wouldn't have to do emissions. I made a spacer with 2 stacked spark plug anti-foulers, so far, so good.

I'm still using the reset tool I bought from you years ago.
 
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