Headers and cats? can they coexist?
Thread Starter
Racer
Joined: Jan 2003
Posts: 270
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From: Erie pa
Headers and cats? can they coexist?
Can you use long tube headers and also use the cats? I want to put the EM long tubes on my 96 LT4, but can I also use the factory cats without trouble? My part of the state just got emission testing this year. Hooray! :smash:
Team Owner
Joined: Sep 2003
Posts: 25,295
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From: I'm the walkin dude I can see all of the world...
St. Jude Donor '03
Re: Headers and cats? can they coexist? (spinedoc)
No you cannot use the Stock Cats with LT headers. You can convert to bullit aftermarket Cats which will work. Some say you can have problems with the visual inspection tho. :nonod:
Instructor
Joined: Mar 2004
Posts: 130
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From: Atlanta GA
Re: Headers and cats? can they coexist? (VictorRussell'92)
Hi Vic, newbie here....Is there a way to open up the exhaust and still pass the smog test?........Atlanta Ga, L-98 no mods yet. I don't wanna put on aftermarket cats and still fail emissions. :confused:
Safety Car
Joined: Mar 2000
Posts: 3,581
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From: Springfield VA
Re: Headers and cats? can they coexist? (Metamando)
Depends on how clean your car is running. My 86 passed emissions (no visual but dyno sniffer) after being bored and stroked, no EGR, LT headers and a single Random Technologies hi-flow cat.
Large Impressive Member
Joined: Jul 2003
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
Re: Headers and cats? can they coexist? (spinedoc)
Hey, I finally figured out a way to use the stock cats on an LT1/4 with long tubes........... Put it on a 4WD chassis, real high in the air, then there' will be plenty of room! :lol: :lol: :lol:
Team Owner
Joined: Sep 2001
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From: Athens AL
C7 of the Year - Unmodified Finalist 2021
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Re: Headers and cats? can they coexist? (Metamando)
Hi Vic, newbie here....Is there a way to open up the exhaust and still pass the smog test?........Atlanta Ga, L-98 no mods yet. I don't wanna put on aftermarket cats and still fail emissions. :confused:
You can pass a sniffer with headers, but you really need a good main cat. Aftermarket cats are usually better at reducing emissions and yet flow better than original.
Le Mans Master
Joined: Jan 2003
Posts: 5,858
Likes: 7
From: Santa Maria CA
Re: Headers and cats? can they coexist? (96LT1)
Depends on how clean your car is running. My 86 passed emissions (no visual but dyno sniffer) after being bored and stroked, no EGR, LT headers and a single Random Technologies hi-flow cat.
My 86 Passed with long tubes, no-pre cats, and with just the main cat. The AIR Pump was disconnected from the exhaust, doing absolutely nothing. Still passed without a problem. Visual is another story though. I run a High Flow Random Tech cat, and have her tuned up nicely. :thumbs:
[Modified by 86PACER, 5:47 PM 3/9/2004]
