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  1. #1
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    Default Anyone running cats?

    Have a stroked LS3 in my Camaro that runs rich. Cant seem to "tune" it out.
    Would running a cat help? Also, getting ready to run a 480HP LS3 in my truck so would apply there also. Thanks

  2. #2
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    I have thought about it a ton of times! I had my AFR dialed in pretty well on the dyno and you still smell exhaust. They have really good high flow cats, I just need to do it!

    Quote Originally Posted by sginphx View Post
    Have a stroked LS3 in my Camaro that runs rich. Cant seem to "tune" it out.
    Would running a cat help? Also, getting ready to run a 480HP LS3 in my truck so would apply there also. Thanks
    1970 Camaro/DSE build


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  3. #3
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    I've been running Walker highflow cats since about 2004-ish. I got tired of the exhaust smell getting on my clothes and crap like that. Also quieted down the exhaust a little which was an added benefit (at least I considered it a benefit... lol). Didn't notice any drop in power.
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  4. #4
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    Sep 2013
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    Default Dynatech metal-core cats

    I'm building a '72 Olds 442 convertible and decided to go with dual cats to minimize the exhaust smell with the top down. I chose DynaTech cats because they have a high-flow, metal core that won't melt down like a ceramic core if they get too hot. I called Dynatech support and the tech said the cores have 300 cells per inch and will flow 396cfm each. He also said the metal cores will light-off more quickly than a ceramic core too. Should be enough flow to support 455cid @ 6000rpm. Here's a link:

    https://www.dynatechheaders.com/stor...tic-converters
    Rodney Meyers
    72 Olds 442 Rest-mod clone

  5. #5
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    Quote Originally Posted by cdrod View Post
    I'm building a '72 Olds 442 convertible and decided to go with dual cats to minimize the exhaust smell with the top down. I chose DynaTech cats because they have a high-flow, metal core that won't melt down like a ceramic core if they get too hot. I called Dynatech support and the tech said the cores have 300 cells per inch and will flow 396cfm each. He also said the metal cores will light-off more quickly than a ceramic core too. Should be enough flow to support 455cid @ 6000rpm. Here's a link:

    https://www.dynatechheaders.com/stor...tic-converters
    Thanks for the link. I have been contemplating this for a few years. Those look like a great way to go.
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  6. #6
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    I've always thought they were a good idea , look at the power levels the manufacturers are chucking at us now , all with cats
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  7. #7
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    Feb 2007
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    Quote Originally Posted by sginphx View Post
    Have a stroked LS3 in my Camaro that runs rich. Cant seem to "tune" it out.
    Would running a cat help? Also, getting ready to run a 480HP LS3 in my truck so would apply there also. Thanks
    If it's actually running too rich, adding cats will not solve that problem. Also, if it's running very rich, the cats may not last long.

    Nick ~
    1969 Cutlass

  8. #8
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    Feb 2013
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    Do you have O2 sensors on both exhaust branches or just 1?

  9. #9
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    Quote Originally Posted by Mr Nick View Post
    If it's actually running too rich, adding cats will not solve that problem. Also, if it's running very rich, the cats may not last long.
    Agreed! I was told not to run cats with a carburetor because the AFR range is too wide with a carb; so I decided to go with a throttle body EFI system. The AFR has to be very consistent for cats to work properly and survive. If the mixture is too rich, the platinum core will overheat and melt, destroying the cat. Ceramic core cats are much more susceptible to damage from overly rich AFRs than are metal core cats.

    Rodney Meyers
    72 Olds 442 Rest-mod clone


  10. #10
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    Mar 2015
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    Yes..running 2 O2 sensors. If I do...I for sure would use metal core over ceramic. Hard to believe more people haven't used them for feedback. Thanks for all the responses so far!

  11. #11
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    I plan on adding cats, but my engine burns a little oil and I need to solve that problem before adding them. Burning oil isn't good for catalytic converters either.

    Nick ~
    1969 Cutlass

  12. #12
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    I really like the idea of running them. After I get my '55 dialed in and stable I will add them to it. I'm glad to hear that it's not that uncommon.
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  13. #13
    Join Date
    Aug 2007
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    200

    Default

    On my E36 LS swap I added the spun cats after a year of driving only to cut down on the exhaust noise. Don't think you are going to get a way from gas smell with the cats. My TJ LS Swap and 68 C10 LS swap don't smell but they had a good quality chassis dyno tune. Neither has cats.



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