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  1. #1
    Tourney3p0
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    Default Removing the cats (88 Vette)

    Hello,

    I just ordered a Power Effects exhaust system for my 88, so I'll be having some exhaust work done in the near future.

    My front two precats have a rattling sound coming from them, and there's some gold dust coming out of the left one. I think this means they're on their way out, so I'm faced with the option of replacing or removing them.

    I was also told that if this was the case, it's probably killed my main cat as well. At 104k miles, it's probably due for a cat change anyway.

    I live in Tennessee, where there is no smog testing. I'm wondering if I'd be able to remove the 2 precats and the main cat, and replace it with a straight pipe. What are my chances of throwing an engine code? Will it hurt or help anything? Or should I simply throw 500 bucks (or more) into a couple of new precats and a main cat?

    I appreciate any help.

  2. #2
    Member -=Jeff=-'s Avatar
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    Corvette(s)
    1990 ZR-1

    Default Re: Removing the cats (88 Vette)

    Originally posted by Tourney3p0
    Hello,

    I just ordered a Power Effects exhaust system for my 88, so I'll be having some exhaust work done in the near future.

    My front two precats have a rattling sound coming from them, and there's some gold dust coming out of the left one. I think this means they're on their way out, so I'm faced with the option of replacing or removing them.

    I was also told that if this was the case, it's probably killed my main cat as well. At 104k miles, it's probably due for a cat change anyway.

    I live in Tennessee, where there is no smog testing. I'm wondering if I'd be able to remove the 2 precats and the main cat, and replace it with a straight pipe. What are my chances of throwing an engine code? Will it hurt or help anything? Or should I simply throw 500 bucks (or more) into a couple of new precats and a main cat?

    I appreciate any help.
    I don't think you will thorw any codes with no cats.. you can try it but back pressure may be too low and cause you to lose power. if so just get a new Main Cat
    -=Jeff=-
    1990 ZR-1 #1051
    ----------------------------------------
    NCM Lifetime Member #978
    ----------------------------------------

  3. #3
    Member Edmond's Avatar
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    Louisiana
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    Corvette(s)
    2003 Z06

    Default

    Places like Ecklers have the front y-pipes without cats. I think going with one of those and a high flow cat would do wonders.

    If my memory serves me well, they're not that expensive (at least compared to other parts).
    Edmond.

    Contact me for the best prices on Amsoil.

  4. #4
    Vettelt193's Avatar
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    Corvette(s)
    none right now :(

    Default

    FYI: Taking out the cats is illegal, and I think it something like a $30,000 fine to the shop that takes them out per cat removed.... so to make a long story short, it may be hard to find a muffler shop that will do the work for you

  5. #5
    Member Edmond's Avatar
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    2003 Z06

    Default

    I do believe that having the front y-pipe is legal, why else would Ecklers sell them? Now, the question is the main cat. Is that legal? Probably not, so people "gut" them.
    Edmond.

    Contact me for the best prices on Amsoil.

  6. #6
    Member
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    Cross Roads, Texas, U.S.
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    Corvette(s)
    '89 dk red coupe

    Default

    Pull the cats; all you have to lose is time - in the quarter mile!
    Reduced backpressure won't "lose horsepower" for you, increased airflow without increased fuel does.
    But you've got a MAF sensor that picks up on things like increased airflow, and adjusts accordingly.
    You stand to gain on the order of 20 - 25 HP; maybe not enough to notice in the seat, but enough to measure at the strip.

    As far as muffler shops not doing this job for you: that's what Sears tools are for. After careful study, you gingerly pick one up...

    And as far as the feds catching you: when was the last time you saw an FBI agent crouched down, peering under a car?

    Besides, nothing's happening in a cat you see "gold powder" coming out of.

    In the off chance that you DO "set a code" after removing the cats, it'll be because there's insufficient exhaust heat to fire up the O2 sensor and get it reading. So you replace them with a heated (3-wire) O2 sensor. In fact, you can do that anyway and improve your fuel economy by getting your system operating "closed loop" quicker.

    - R

  7. #7
    Member
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    Nov 2001
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    Savannah, GA, USA
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    Corvette(s)
    87 Silver Coupe Way over 200k miles

    Default

    A bent 3ft long piece of 1/2 inch iron pipe will break out the pre cats and a straight piece will clean out the main cat.
    Didn't cause any problems on an 87. It made a BIG difference in sound.
    Take the cat loose at the rear Y pipe and the front off at the manifolds.

    JS

  8. #8
    New Member
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    Oct 2002
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    ohio
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    Corvette(s)
    1988 COUPE

    Default pup cats

    I removed the front smaller two cats on my 88 and replaced them with a straight through y-pipe and left only the main cat. Car runs great and passed the emissions test for ohio (cleveland region).

  9. #9
    Member
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    Corvette(s)
    '89 dk red coupe

    Default Re: pup cats

    Originally posted by Len Imbrogno
    I removed the front smaller two cats on my 88 and replaced them with a straight through y-pipe and left only the main cat. Car runs great and passed the emissions test for ohio (cleveland region).
    That's because the pups are just "lightoff" cats and aren't needed once the car is warmed-up and the underbody cat is working.
    - R

  10. #10
    Member Edmond's Avatar
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    Default

    Redbob,

    What that means is that the pup cats only disrupt air flow once the big cat is warmed up?

    If you fail emissions, it doesn't have anything to do with the pup cats because the car will pass with just the big cat working properly?
    Edmond.

    Contact me for the best prices on Amsoil.

  11. #11
    Member
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    Corvette(s)
    '89 dk red coupe

    Default

    Originally posted by Edmond
    Redbob,

    What that means is that the pup cats only disrupt air flow once the big cat is warmed up?

    If you fail emissions, it doesn't have anything to do with the pup cats because the car will pass with just the big cat working properly?
    Exactly.

  12. #12
    johnny
    Guest

    Default i removed the cats

    I removed the cats, and installed a 1 3/4" tpis headers and a 2,5 " B&B tri-flow system, there is no muffler in the middle, only the two mufflers at the rearend.

    What happend (first of all the sound is awsome) the engine had some fuell loss in the range till 2000 rmp, I have a 86 vette and as far I know, there is no chip for it.

    Now I have a sequential DTA race system installed and the problem is solved. I think you should first inform yourself if the is a right chip. I recomend TPIS.

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