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Removing cats permanently - is a test pipe all I need?

Discussion in 'Gen 2 Prius Accessories & Modifications' started by Waco440, May 10, 2020.

  1. Waco440

    Waco440 Junior Member

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    I am going to be permanently removing the cats on my 2007 Prius. That being said, is there a direct bolt in replacement for this space or will a muffler shop have to fab up a straight pipe? I found "test pipes" online, are those pipes direct replacements of the cats?

    SM-G986U ?
     
  2. Mendel Leisk

    Mendel Leisk Senior Member

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    Welcome. Just joshing, this sounds like the quintessential cruelty to felines thread...

    If you need to get the car through an inspection, the lack of O2 sensors will maybe nix the plan?
     
  3. sam spade 2

    sam spade 2 Senior Member

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    AND in some (most?) states, a real muffler shop won't do that because it is technically illegal, even if that area does not have mandatory testing.
     
  4. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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  5. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Theoretically yes. They are made to be installed temporarily when performance-testing a car on a dynamometer or race track.

    The trouble is, I don't think you'll be likely to find one meant for your Prius, because not very many racers are operating a Prius. There's not much demand for a prefab specialty part like this.

    If you make one yourself and ignore the P0420 error light you'll probably do okay. In some states you might be able to get a muffler shop to fabricate one for you, but in other states they may decline the job due to state emissions law.
     
  6. Waco440

    Waco440 Junior Member

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  7. Waco440

    Waco440 Junior Member

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    I won't have a problem with that. Thanks

    SM-G986U ?
     
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  8. Mendel Leisk

    Mendel Leisk Senior Member

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    @JimboPalmer interesting link. But what's happening in the last sentence; maybe I should turn on the news:

    upload_2020-5-11_6-59-14.png
     
  9. ETC(SS)

    ETC(SS) The OTHER One Percenter.....

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    Answer to the question:
    No.
    In my 10 years with Priuses I've never heard of one.
    As mentioned above, "test pipes" are not commonly used on vehicles powered by a 4 cylinder Atkinson engine.

    As Jimbo pointed out It would probably be cheaper just to put a non-oem cat back on.

    If you're looking for performance or fuel economy improvements....getting rid of the cat isn't going to do it - especially on an 07, and there are less-restrictive cat-back options to give you the fart-can sound or other "benefits".....real or imagined that you might be looking for.
     
    #9 ETC(SS), May 11, 2020
    Last edited: May 11, 2020
  10. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    I am not sure exactly how you typo New York into Chile, but I suspect it takes the repeated application of alcohol.
     
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  11. fotomoto

    fotomoto Senior Member

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    Common modification the m/c world when chasing max hp gains from intake/exhaust mods and lowering weight. A straight pipe is welded inside the gutted cat which was cut opened from the top/unseen side. O2 sensor eliminators are needed for the CEL you'll get. Some muffler shops will do it for off-road/competition use or a welding shop will do it no questions asked.

    GOOD LUCK!
     
  12. fotomoto

    fotomoto Senior Member

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  13. Waco440

    Waco440 Junior Member

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    Waco is nearest big town to me. Thanks, I'll keep that for when my batteries go down the road.

    SM-G986U ?
     
  14. fotomoto

    fotomoto Senior Member

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    Matt offers several (common) repair services also. Remember, these are drive-to-you offers and you should be in his 150 mile service area.
     
  15. The Electric Me

    The Electric Me Go Speed Go!

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    When I read the headline, I thought I was going to have to report this thread to PETA or the Humane Society.
     
  16. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    In theory it bolts to the manifold and there is an included clamp to attach to the rest of the exhaust. I would consider welding it to the rest of the exhaust to reduce noise, but that is me.
     
  17. ydpplqbd

    ydpplqbd Active Member

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    If you go this route, you can likely avoid the P0420 CEL with a simple mod. On ebay, O2 extenders are sold with catalyst built in. IOW, catalyst only catalyzes air/fumes analyzed by the downstream O2 sensor which should avoid the P0420. Food for thought.
     
  18. dorifutoben

    dorifutoben New Member

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    My cat got stolen 4 nights ago.. Thinking of doing the same thing as OP. They can't steal a cat again if there isn't any O.O My question is how much louder would it be? Has anyone this? Replacing only the section from the flange up to the resonator?
     
  19. ETC(SS)

    ETC(SS) The OTHER One Percenter.....

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    P.C. Answer:
    You should always replace a cat with a cat. If you live where they make you pay a special tax for driving Priuses and you have to replace an OEM cat with an OEM cat, then you should do your part to save the planet, the whales, Toyota manufacturing, etc...etc...

    Real World Answer:
    If you live on free soil, you should consider replacing the OEM cat with an aftermarket unit, and keeping the O2 sensor where it is.
    Your car will run more efficiently and you'll still be doing your part to lower car emissions.

    However (comma!!) I can report that there are about 432,000 ways that you can bypass the cat and I can also report that a test pipe to the muffler will leave your car sounding much like it did before your cat was stolen (catnapped?)
    I mentioned the PC answer first NOT to curry favor with the eco-chic in the forum (NOTHING could accomplish THAT!) but rather because aftermarket catalytic converters are inexpensive enough to warrant putting a cat back into the car, although I would also consider clearly labeling it as a NON OEM unit to make it less attractive for thieves wanting to use it on the black market.

    Good Luck!
     
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  20. oldtechaa

    oldtechaa Active Member

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    Aftermarket cats really are quite cheap, it's illegal to remove the cat permanently no matter where in the US you may live (even though without inspections it won't really be discovered) and the benefits are immense. Please just put an aftermarket cat on. There's no downside to it. You could remove and sell the OEM cat, install an aftermarket cat, and make a profit on it. You haven't said why you want to remove it, though.
     
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