LT1-LT4 Modifications 1993-97 Gen II Small Block V8

Adding a Cat

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Old Apr 6, 2010 | 09:07 PM
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Default Adding a Cat

I'm thinking about adding a high flow cat to my car to help tame the noise some and to reduce the raw fuel smell to make the car a little more liveable on a daily basis. with a decent size cam'd 383 (230/242 111LSA; 12:1+ CR) would there be any issues with this?

Last edited by myltwon; Apr 7, 2010 at 08:01 PM.
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Old Apr 6, 2010 | 11:12 PM
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I'm running dual Random Tech metal matrix converters in a custom y-pipe off of LPP's for the exact reasons you mentioned. While I'm running a pretty tame setup compared to you, I think they should work great for your setup as well. Give Random Tech a call if you have any questions.
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Old Apr 7, 2010 | 08:36 AM
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Yeah, my wife complained about the raw fuel smell, especially at startup, but I told her that was what car's used to smell like before the EPA got involved. Mine isn't a daily driver though so it's not that bad really.

I would be interested to know how much performance loss in associated with adding a cat though.
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Old Apr 7, 2010 | 09:33 AM
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Ya big weenie!!! Race cars are supposed to be loud.
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Old Apr 7, 2010 | 09:34 AM
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Originally Posted by joeZ96
I'm running dual Random Tech metal matrix converters in a custom y-pipe off of LPP's for the exact reasons you mentioned. While I'm running a pretty tame setup compared to you, I think they should work great for your setup as well. Give Random Tech a call if you have any questions.
^^X2.

I'm running a pair of 144-30000 converters. These are the 100-cell/in. race cats and completely got rid of my 'eyes-burning raw fuel' smell when I first completed my mods. The 7000 series are rated at 617cfm flow and are 300-cell/in. The race-only 100-cell/in. are rated IIRC to around 730cfm EACH.

Randoms are expensive (higher washcoat concentrations of rhodium, platinum and palladium) but they're the best if you need to run converters. The Magnaflows are an inexpensive choice ($95.00- $120.00 each) but I've heard of a lot of them telescoping their guts/ blowing out. I got my Randoms from Ray at Ultrarev in NJ. The 144s are new enough they likely get drop-shipped direct. Below is an internal view of a metal-matrix 300-cell/in. converter to give you an idea.
Attached Thumbnails Adding a Cat-metal-matrix.jpg  
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Old Apr 7, 2010 | 05:16 PM
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Originally Posted by garage_queen
Ya big weenie!!! Race cars are supposed to be loud.
lol shut up rick

if my car was faster I'd have no problem being a loud ******* but the whole dragging the exhaust/cop magnet thing gets old when it's just an 11 second car.
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Old Apr 7, 2010 | 05:46 PM
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any idea how much volume reduction 2 highflow cats would add?
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Old Apr 7, 2010 | 10:09 PM
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My car is close to stock so not much of a comparison... but, I had a hollowed out cat and i switched to a high flow magnaflow. It quieted it down some. Not alot. It felt like it had more torque on the low end and sounded better up top too.
But im still unhappy with the exhaust on my car. It has the Slp Lm1. Too raspy and i dont even have headers yet.
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Old Apr 7, 2010 | 10:12 PM
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yeah definately not a fan of the SLP LM1, I had one with stock manifolds and I thought it sounded decent (hell I paid $75 for it), added headers then it got pretty damn loud, added a cam then it was unbearable so ditched it asap
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Old Apr 7, 2010 | 10:18 PM
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Originally Posted by myltwon
yeah definately not a fan of the SLP LM1, I had one with stock manifolds and I thought it sounded decent (hell I paid $75 for it), added headers then it got pretty damn loud, added a cam then it was unbearable so ditched it asap
Yeah it was on the car when i got it. Plan to switch it up soon. Not sure what i wanna do yet. Saw a Borla catback on craigslist for 250 not too long ago shoulda jumped on it.
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Old Apr 8, 2010 | 02:11 PM
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Originally Posted by myltwon
lol shut up rick
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