changing cat converters out when changing muffler?

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BlueCollarTahoe

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looking to put a flowmaster 44 on the truck soon...was wondering is it worth changing the cats while im at it? theyre the factory ones and truck is at 112k miles. im in NYC so they have to pass the emissions test

2004 tahoe 5.3 v8 lt
 

swathdiver

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She's almost fifteen years old and the mileage is about when mine went bad. If you have the funds do it. Don't skimp out and get cheap no name brands, they'll choke your motor and do not last. I bought the Magnaflow Y-Pipe with cats for mine. Flowmaster 44s, you'll be hard of hearing soon enough if you're not already! Sound great though. You adding a resonator to kill the drone?
 

Doubeleive

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I would say no unless you have been driving the piss out of it for a good long time then the cat's should be fine, you will want to change the 02 sensors though (all of them) there only rated for 100k but could go longer
 
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BlueCollarTahoe

BlueCollarTahoe

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She's almost fifteen years old and the mileage is about when mine went bad. If you have the funds do it. Don't skimp out and get cheap no name brands, they'll choke your motor and do not last. I bought the Magnaflow Y-Pipe with cats for mine. Flowmaster 44s, you'll be hard of hearing soon enough if you're not already! Sound great though. You adding a resonator to kill the drone?

shes a strong old woman lol no resonator! lets hear the drone!!! you got a parts number for that set up? i was looking at whole setups from magnaflow and flowmaster. ill save up to get it done.

I would say no unless you have been driving the piss out of it for a good long time then the cat's should be fine, you will want to change the 02 sensors though (all of them) there only rated for 100k but could go longer

i changed the driver side 2 maybe 10k miles ago....the passenger side ones are the stock ones from the factory.
 

HoeRyder26

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I wouldn't bother. Unless you have a check engine light on for the efficiency or you feel like you have lost power, you would be wasting your money. You would be surprised how good the stock cats flow.
 
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BlueCollarTahoe

BlueCollarTahoe

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is there a full proof way to test their efficiency? even a test a diag shop can do? or is that what the 02 sensors are for?
 
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