Pre cats
Instructor
Joined: Nov 2015
Posts: 231
Likes: 32
From: Cumming Georgia
Normally there is a ceramic matrix, coated with Platinum & Palladium that heats up and helps to remove the nastys in the exhaust....But they can clog over time, which significantly reduces performance.
D.
D.
Melting Slicks
Joined: May 2018
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From: Question Government
https://www.magnaflow.com/catalytic-...ic-converters/
Racer
Joined: Apr 2017
Posts: 396
Likes: 58
From: Katy Texas
In my case "significantly reduces performance" meant the matrix fell apart and both dumped their contents downstream totally plugging the center main cat leaving me stranded. A local exhaust shop cleaned the center out, blew out the rest with the throttle and all was good. Car sounds better too. My 89 is old enough to not require emissions inspections in my state.
Drifting
Joined: Mar 2011
Posts: 1,693
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From: on Barnegat Bay Joisey
some folks call those small round cans "resonators". I removed them when I replaced the main cat. It changed the exhaust note to more of a rumble with a crackle sound when I backed off the throttle. Nice 
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Drifting
Joined: Feb 2008
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From: NE Ohio
2024 C4 of the Year Finalist - Unmodified
Drifting
Joined: Mar 2011
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From: on Barnegat Bay Joisey
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Drifting
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From: on Barnegat Bay Joisey
Team Owner
Joined: Sep 2001
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From: Athens AL
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Its a regular ceramic matrix, looks like a tiny grid.
Removing and replacing with a Catless front Y probably won't do any droning if youre not increasing pipe diameter. The main cat will tend to cancel it out. It will be more aggressive sounding but not crazy.
Removing and replacing with a Catless front Y probably won't do any droning if youre not increasing pipe diameter. The main cat will tend to cancel it out. It will be more aggressive sounding but not crazy.
