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How many Cats?

Discussion in '2nd Gen. Tacomas' started by simonreale, Jun 13, 2009.

  1. Jun 13, 2009 at 4:16 PM
    #1
    simonreale

    simonreale [OP] Well-Known Member

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    Hey Guys,

    Just wondering, does the 4L V6 motor have 2 catalytic converters or 4?

    Thanks
     
  2. Jun 13, 2009 at 4:19 PM
    #2
    simonreale

    simonreale [OP] Well-Known Member

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    I thought so, so when upgrading, should we replace all 4 with hi flow cats or just 2?
     
  3. Jun 13, 2009 at 4:37 PM
    #3
    simonreale

    simonreale [OP] Well-Known Member

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    Myns got the TRD supercharger
     
  4. Jun 13, 2009 at 4:45 PM
    #4
    simonreale

    simonreale [OP] Well-Known Member

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    Nope, only if they are suspicious of something, and with a new truck they wont be.
     
  5. Jun 13, 2009 at 5:22 PM
    #5
    simonreale

    simonreale [OP] Well-Known Member

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    Ive already bought new headers, 2 new cats and muffler, I only realised now that theres actually 4 cats, instead of 2.

    So im just wondering, do people here replace all 4 or get rid of 4 and run just 2 aftermarket units?
     
  6. Jun 13, 2009 at 5:30 PM
    #6
    johnecon2001

    johnecon2001 Well-Known Member

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    Phoenix, AZ
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    Downey front skid, Trail Gear U-Bolt flip, Toytec AAL, Total Chaos UCA's, Bilstein 5100's x4 + Eibach adjustable coils, Doug Thorley Long Tube Headers, Custom Rear bumper, TRD OffRoad front tow hook, TRD Trail Team wheels, Federal Couragia M/T 265's, ARB rear locker + on board air (CKMA12), TRD shift knob, Alpine W205, TRD seat covers, Tom Woods 1 Piece drive shaft, Powermaster D2700, Stubbs HD-SKO Sliders.
    Skip swapping the front cats. Just get a set of Doug Thorley Long Tub headers.
     
  7. Jun 14, 2009 at 2:45 AM
    #7
    simonreale

    simonreale [OP] Well-Known Member

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    Ive already got the headers, any oppinions on what I should do?
     
  8. Jun 14, 2009 at 6:38 AM
    #8
    Janster

    Janster Old & Forgetful

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    A little off topic (maybe) - but the lower 2 cats.... One of mine has a metal shield around it and the other one doesn't?

    What's up with that? Or does one get hotter than the other prior to where the pipes combine (after the cats)?
     
  9. Jun 14, 2009 at 6:58 AM
    #9
    chris4x4

    chris4x4 With sufficient thrust, pigs fly just fine. Staff Member

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    Its my understanding that the driver side has the heat shield, as the fuel lines run down that side....I really never bothered to look into this. :)
     
  10. Jun 14, 2009 at 6:18 PM
    #10
    simonreale

    simonreale [OP] Well-Known Member

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    Both my lower cats have a heat shield, the 2 upper cats dont.
     
  11. Jun 14, 2009 at 6:34 PM
    #11
    98tacoma27

    98tacoma27 :POOPCORN: Staff Member

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    You can remove the rear 2 cats without harming anything.
     
  12. Jun 14, 2009 at 7:37 PM
    #12
    simonreale

    simonreale [OP] Well-Known Member

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    So I should replace the ones that come off the headers with Hi-flows, and ditch the second pair?
     
  13. Jun 14, 2009 at 7:45 PM
    #13
    98tacoma27

    98tacoma27 :POOPCORN: Staff Member

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    You can, but I am uncertain as to how the sensors will respond to the high flows. I have heard reports of ECU's not "liking" high flow CAT's. I mean you may throw a CEL (check engine light) code for a faulty CAT even though it will function properly. There is also a way around this though.

    Here is a possible scenario: You replace the front 2 CAT's (they are the only ones the ECU monitors) with the high flows. The ECU throws a P0420 (bad CAT code). This code will be genereated from the reading of the rear O2 sensor. It will register Bank 1, 2, or both.

    The correction: You can purchase an O2 simulator from URDUSA.com that will tell the ECU the CAT(s) are fine.
     
  14. Jun 14, 2009 at 7:47 PM
    #14
    simonreale

    simonreale [OP] Well-Known Member

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    Thanks heaps for your help, in Australia no one has modified there V6 exhaust really as they are all about D4D (diesel) power on there hiluxs.

    So this set up, with only 2 hi-flow cats should improve power through out the whole range?

    Thanks
     
  15. Jun 14, 2009 at 7:51 PM
    #15
    98tacoma27

    98tacoma27 :POOPCORN: Staff Member

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    If I were in your shoes using your ideas, this is how I would approach it. I would replace the front CAT's with the high flows and monitor the performance for at least four tank fills. If no negative effects are noticed (ie: CEL's, performance losses, etc), I would consider it a success.

    If the truck throws a CEL(s) for bad CAT's, I would purchase the O2 simulator.

    Keep the stock set-up in case you should have to go back to it at a later time. The second set of CAT's are unnecessary.
     
  16. Jun 14, 2009 at 7:54 PM
    #16
    98tacoma27

    98tacoma27 :POOPCORN: Staff Member

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    I cannot answer that question with certainty. I would suggest running a set of before and after dyno's to verify any performance change.
     
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