News

Looking for broken cats (1995 - 355)

Discussion in '348/355' started by andrewmr, May 13, 2008.

  1. andrewmr

    andrewmr Formula Junior

    Jun 7, 2005
    317
    Bucks County, PA.
    Full Name:
    Michael
    With all the threads around about bad cats I was thinking I'd like to try an experiment. Does any one have a pair of bad cats laying around that they'd like to get rid of?


    Michael
    215-589-5633
     
  2. To remove this ad click here.

  3. 285ferrari

    285ferrari F1 World Champ
    Sponsor

    Sep 11, 2004
    19,958
    Southern Md
    Full Name:
    Robbie
    There was a set of hollowed out cats on Ebay the other day
     
  4. andrewmr

    andrewmr Formula Junior

    Jun 7, 2005
    317
    Bucks County, PA.
    Full Name:
    Michael
    I was bidding on them, but got beat out at the end...
     
  5. SGM

    SGM F1 Rookie
    Owner

    Sep 27, 2006
    2,649
    Northern VA
    Full Name:
    Steve
    What is your experiment??
     
  6. spider348

    spider348 Formula 3
    Silver Subscribed

    Nov 3, 2003
    1,176
    MA
    Full Name:
    John
    There is a set on ebay now.
     
  7. To remove this ad click here.

  8. andrewmr

    andrewmr Formula Junior

    Jun 7, 2005
    317
    Bucks County, PA.
    Full Name:
    Michael
    I want to see what the difference in flow (and resulting power) between a stock cat, a failed cat and ultimately no cat.
     
  9. 348guy

    348guy Karting

    Nov 28, 2007
    163
    Ashburn, VA
    Full Name:
    Rob
    How will you measure the flow differences?
     
  10. andrewmr

    andrewmr Formula Junior

    Jun 7, 2005
    317
    Bucks County, PA.
    Full Name:
    Michael
    I was thinking of putting them on a flow bench.

    And of course the doing some dyno work.

    Another question about them is how they fail. BMW 7 series cars seem to have a number of problem cats out there. I was wondering if they fail in the same manor and if there's a similar solution to the repair.
     
  11. f355spider

    f355spider F1 World Champ
    Rossa Subscribed Owner

    May 29, 2001
    17,245
    USA
    Full Name:
    Hugh G. Rection
    My personal experience, (and what I have seen pictured a number of times on fchat), is the cores in the oem Ansa cats come loose. Once loose, they rotate around, which slowly grinds down the core from the outside. Initially, the core will stay oriented in the correct direction, as they are longer than they are wide, but the exhaust will go around it, rather than through it (which will likely throw a "check engine" light for low cat efficiency). Since the core, as it wears down, will no longer be oriented in the correct direction, exhaust flow can become restricted as it has to go around, rather than through the core....this also lowers the cat efficiency, tripping the "Check Engine" light. As it gets worse, the cores will start to crumble and break apart (I would suspect that only happens to those that either repeatedly clear the light with a code reader without replacing the cats, or simply ignore the CE light).

    The factory cats can be repaired, by having them cut open, new cores properly secured, and the housings welded back up.
     
  12. To remove this ad click here.

  13. andrewmr

    andrewmr Formula Junior

    Jun 7, 2005
    317
    Bucks County, PA.
    Full Name:
    Michael
    Are the cores simialr to the old honeycomb (similar to a bee hive) construction or are they encased in metal inside the cat?


    Speaking of CEL, is this a problem with 1995 cars? I can see where it might be a problem with the later cars as they have sensor before and after the cats but I would think the single sensor on 1995 cars would be ok. Or am I mistaken?

    If the CEL light is an issue, how do they work around it for track cars without cats?
     
  14. andrewmr

    andrewmr Formula Junior

    Jun 7, 2005
    317
    Bucks County, PA.
    Full Name:
    Michael
    I saw these.....

    Is there a difference between the years? I have a 95 car (2.7) will the ones for later cars (5.2) work?
     
  15. ferrariwant2be

    ferrariwant2be Karting

    Jan 14, 2008
    87
  16. f355spider

    f355spider F1 World Champ
    Rossa Subscribed Owner

    May 29, 2001
    17,245
    USA
    Full Name:
    Hugh G. Rection
    The only difference (so I hear) is the 5.2 had the post cat O2 sensor fitting. So you can use a 5.2 cat on a 2.7 if you put a plug (cap screw) on the second O2 bung.
     
  17. f355spider

    f355spider F1 World Champ
    Rossa Subscribed Owner

    May 29, 2001
    17,245
    USA
    Full Name:
    Hugh G. Rection
    Cores are honeycomb looking.
     

Share This Page