Anyone gutted their catalytic converter? | FerrariChat

Anyone gutted their catalytic converter?

Discussion in '308/328' started by Irishman, Nov 13, 2021.

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  1. Irishman

    Irishman F1 Rookie

    Oct 13, 2005
    3,524
    Raleigh
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    Kevin
    Anyone gutted their catalytic converter? I'm curious about the effort involved, plus how the car ran and sounded afterwards.

    In the state where I live the car no longer requires inspection. I also find it difficult to imagine a 42-year old catalytic converter is still doing anything useful.

    Other options I've considered are test pipes (why do they cost so much?). Or the elusive European ANSA version of the exhaust system.
     
  2. Dave Bertrand

    Dave Bertrand Formula Junior
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    Dec 24, 2005
    824
    Castle Rock, CO
    Actually a cat wears out from mileage, not time. It should last 100k+ miles. You can probably sell your good cat for enough money to buy two test pipes, so I'd suggest that instead of destroying your perfectly good one.

    Case in point: my '86 911's original cat was still working great at 140k miles.
     
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  3. thorn

    thorn F1 Rookie
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    Aug 7, 2012
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    Agreed. The cat would have value to people in places such as California, where OEM components are mandated.
     
  4. Mark C Harvey

    Mark C Harvey Formula Junior

    Jul 17, 2018
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    West Hartford, Connecticut
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    Some folks find the fumes too much after cat delete (me included). Suggest you keep your cat in case you want to go back to stock. An exhaust shop should be able to fabricate and fit a test pipe for you - Cheap.
     
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  5. ginoBBi512

    ginoBBi512 F1 Rookie
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    Oct 9, 2016
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    Why would anybody do that ? Buy a test pipe instead , and while your at it, why not a Tubi .

    Thank you
     
  6. miketuason

    miketuason F1 World Champ
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    Feb 24, 2006
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    I have gutted a pair of of really bad cat from a two cat 308 and use them as test pipe, it works really well.
     
  7. eulk328

    eulk328 F1 Rookie

    Feb 18, 2005
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    To help pass a visual-only inspection in some places/countries. Unannounced roadside police inspection etc.
     
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  8. ragtop1

    ragtop1 F1 Veteran
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    Nov 11, 2006
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    +100 I can also attest to that
     
  9. RodC328gts

    RodC328gts Formula Junior

    Aug 17, 2021
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    Mexico
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    Rod C
    Why not using a modern sports cat?

    @Fabspeed Motorsport sells one. I purchased mine there on august, I hope one day they will ship it.
     
  10. ragtop1

    ragtop1 F1 Veteran
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  11. mike996

    mike996 F1 Veteran

    Jun 14, 2008
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    "Why not using a modern sports cat?"

    Certainly that's an option but the Cats and "test pipes" from the typical aftermarket "sports" suppliers are insanely priced. As noted, any exhaust shop can provide cats/test pipes for a fraction of the "sport" price.
     
  12. Nino1964

    Nino1964 Formula Junior
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    Aug 14, 2015
    302
    North Georgia
    I have not gutted but I replaced oem original fit and the stink factor much improved with new cats. No significant bhp increase without cats, so replacing with new may help with stink factor. I submitted a write up on an aftermarket set up that worked well for my GT4.
     
  13. kcabpilot

    kcabpilot Formula 3

    Apr 17, 2014
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    I made two test pipes, I think it was less than $50 for the flanges, pipe and gaskets. I put the cats and air pump in storage in case anyone ever wants to put them back on.
     
  14. ginoBBi512

    ginoBBi512 F1 Rookie
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    Oct 9, 2016
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    Not in 21 years , I smog the car every 2 years by swapping out the test pipe for the cat ,

    Thank you,
     
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  15. eulk328

    eulk328 F1 Rookie

    Feb 18, 2005
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    Sure, lots of people do that.

    There may be no such thing as a random stop or a checkpoint where you happen to live. The world is a big place. There are places where it happens. There are places where the police check tire tread depth of vehicles parked in public. There are places where dashcams are illegal etc. etc.
     
  16. eulk328

    eulk328 F1 Rookie

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  17. tuttebenne

    tuttebenne F1 Rookie

    Mar 26, 2003
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    Cats can last a long long time. I've got cats on my mid 80s Benzes that are over 30 years and 200k miles old and they still work. Not sure what quality cats Ferrari used but I think its a safe bet the exhaust will stink when the cats are gone.
     
  18. mike996

    mike996 F1 Veteran

    Jun 14, 2008
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    Funny - one of the primary objections when cats were introduced in the 70's was the rotten egg smell produced by them. You could always tell, sitting at a stoplight, if the car in front of you had a Cat! Back then, cats produced a stinky smell; properly tuned cat-less engines did not. Go figure...
     
  19. thorn

    thorn F1 Rookie
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    Aug 7, 2012
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    Here's a listing at Summit - prices might be lower than you'd expect: https://www.summitracing.com/search/part-type/catalytic-converters

    Of course, you'd need to make sure the car has the proper A/F and exhaust gasses at acceptable levels... if you're already running rich, you'd just poison it.
     
  20. eulk328

    eulk328 F1 Rookie

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    They sure are and Summit is known legit. Didn't think you could get something like for what seems like a reasonable price.
     
  21. mike996

    mike996 F1 Veteran

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    It's inexpensive because it doesn't have some boutique 'performance shop' label on it! OTOH, If you need a chrome Cat so all the folks who regularly crawl under the car can see it/be impressed, you'll have to pony up the $1000 for a boutique cat!:rolleyes:
     
  22. Dave Bertrand

    Dave Bertrand Formula Junior
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    Dec 24, 2005
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    Castle Rock, CO
    They're also cheap because they're universal fit, which means they don't come with flanges or the labor to weld them up. I'll bet they also don't contain much catalyst in them so would need to be replaced every 15-20k miles.
     
  23. mike996

    mike996 F1 Veteran

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  24. tuttebenne

    tuttebenne F1 Rookie

    Mar 26, 2003
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    Mike, I remember those days. It seems that whenever I come up on a car without a cat, I can smell it a good 1000 ft before catching up to the offending car. But I certainly have no experience with cat-less QVs or the earlier injected 308s. Would they run lean without a cat?
     
  25. mike996

    mike996 F1 Veteran

    Jun 14, 2008
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    The OEM tuning would be lean at the idle/low speed range for use with the cat/low emissions. If you remove the cat, in theory the mixture doesn't change and there would be no difference in how the engine runs. but the O2 sensor - if still enabled - would signal the system to adjust the mixture appropriately. I'm GUESSING that it would see the Catless output as slightly rich and try to lean the mixture even more but I really don't know.
     

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