100 cell or 200 cell cats

Discussion in 'E46 M3 (2001-2006)' started by robmarrs, Nov 8, 2018.

  1. 8 Nov 2018 at 10:46 PM #1
    robmarrs

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    I want to replace the std cats for some more track orientated ones.

    Are both 100 & 200 cell going to pass the MOT?

    Are they both going to exhibit more noise than std?
     
  2. 8 Nov 2018 at 10:53 PM #2
    grchmason

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    I'm sure standard E46 Cats are already 200 cell :beer:
     
  3. 8 Nov 2018 at 11:04 PM #3
    robmarrs

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    400 I believe.
     
  4. 8 Nov 2018 at 11:43 PM #4
    James92

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    Yeah I thought standard were 400 and CSL are 200
     
  5. 8 Nov 2018 at 11:55 PM #5
    grchmason

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    I could well be wrong apologies if so, but i'm sure I was told they are 200 cell :suicide:
     
  6. 9 Nov 2018 at 12:00 AM #6
    James92

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    In that case I have no idea haha
     
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  7. 9 Nov 2018 at 12:04 AM #7
    grchmason

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    Me and you both lol! :muttley::lolwsign:

    .
     
  8. 9 Nov 2018 at 12:59 AM #8
    STAATS

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    There is a report on the design of the E46 M3 Exhaust System here:
    www.unofficialbmw.com/images/BMW_M3_Exhaust_System.pdf

    Clearly states in Section 4.2.1 200cell cats for the standard M3. I personally don't believe there is any evidence other than pure conjecture that the CSL had different cats to the standard M3... it seems crazy that it would given it had more aggressive cams and exhaust valves which would have harmed emissions, to have reduced the cats as well seems nonsense.

    I think the mix up between 400 and 200 is peoples understanding of how to quote it... They are 200Cell.psi so its a statement of cells per area... I believe some people double that number as there are 2x cats... but this is wrong... So vendors state (liek VAC for instance: https://store.vacmotorsports.com/su...metallic-cat-use-w-stepped-headers-p2096.aspx)that OE was 400cell and Supersprint is 200cell but I can definitively say that OE is 200cell and then I guess that Supersprint are actually 100cell... which I believe I have read somewhere but I cannot confirm.
     
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  9. 9 Nov 2018 at 1:17 PM #9
    grchmason

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    I thought I was right :grouphug:
     
  10. 9 Nov 2018 at 1:18 PM #10
    robmarrs

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    Well thats my knowledge well and truely corrected, interesting article, thanks for sharing the knowledge. 100 cell it is then.
     
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  11. 9 Nov 2018 at 1:25 PM #11
    wivvy 03

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    I've got 100cell Miltec cats on mine and it passes it's MOT no problem.
     
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  12. 9 Nov 2018 at 8:12 PM #12
    MWagon

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    100 cell twin cats should pass mot emissions easy. As long as map is good,healthy engine and the cats get properly hot you’ll get a pass no problem.
     
  13. 9 Nov 2018 at 8:16 PM #13
    DiM3ch

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    The csl uses thinner material for the whole exhaust (exhaust manifolds are the same on the regular M3 after 2004ish) so the internals are the same but weigh less. OEM cats are 200 cell
     
  14. 9 Nov 2018 at 11:09 PM #14
    Karl 04lsb

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    I’ve got a set of milltek/hjs motorsports 100 cell cats for sale if interested
     
  15. 10 Nov 2018 at 12:50 AM #15
    STAATS

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    I'm glad to hear that you can pass MOT with 100cell cats. Can I ask if anyone has passed with 100cell cats with a CF airbox and cams? (280/272 or 288/280)? I need to pass an emission test and I have just gone to CF airbox, 280/272, full supersprint sports exhaust with 100cell cats... so I am hoping I can pass... the engine is rebuilt and running rich at the moment but after i break it in I hope to get it tuned to something better.
     
  16. 10 Nov 2018 at 8:11 AM #16
    Martyn

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    US M3s have 400 cell cats as standard.
    Euro M3s all have 200 cell cats as standard.

    Unless you've changed your injectors then no tuner should be touching the part throttle / idle tables so the ECU should hold a steady 14.7:1 at idle / fast idle providing the following:

    - The fuel trim limits havent been exceeded.
    - There are no exhaust leaks pre-cat.
    - There cats are high quality and are up to temp
    - Your O2/Lambda sensors arent knackered.
     
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