Catalytic Converters cause performance reduction?

I just put a Flowmaster catback system on my '89 Formula. The car ran great for a couple month but now at least one of my dual catalytic converters has started to rattle. The guys at the shop say its the
heat shield. I've also noticed significant reduction in throttle response. The car idles fine, it just doesn't accelerate. Not knowing much about catalytic converters, I'd like to know if is it possible that the converters are causing this reduction in power or if I've developed another simulatenous problem?
Tom
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: I just put a Flowmaster catback system on my '89 Formula. The car ran : great for a couple month but now at least one of my dual catalytic : converters has started to rattle. The guys at the shop say its the : heat shield. I've also noticed significant reduction in throttle : response. The car idles fine, it just doesn't accelerate. Not : knowing much about catalytic converters, I'd like to know if is it : possible that the converters are causing this reduction in power or if : I've developed another simulatenous problem?
: Tom
Certainly a loose heat shield would not cause any acceleration problems.
The only time a converter causes problems is when it becomes blocked over time. Similar to if an old muffler becomes clogged with rust/crud.
Marshall G. Ward, III
1996 T/A, WS6, 6-Speed, Med Dk Green, Hardtop, T43 Spoiler, 10 Spk CD, Pwr Ant, Graphite cloth, Pwr seat, Keyless entry w/alarm, Leather Appointments Group MODS: !CAGS, K&N, Synthetic Engine/Trans/Diff fluid, Magna Flow Muffler Hotchkis 2 pt STB and SFC's, B&M Ripper shifter License Frame:"One of 2051/1996 Ram Air Trans Am" License Plate: "RAIR TA"
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A backpressure tester would work wonders here and any exhaust shop can do this check for you.
If the converters are stuffed up, there's a problem with the way the engine runs. In theory, cats last a long time, typically the life of the car if the engine is kept in tune.
Many people replace a cat with a new one only to have it stuff again. It's attacking the symptom, not the cause.
I've yet to change a converter on any of my GM cars and they are 20+ years old. Joe--ASE Certified Parts Specialist & 10th Ann.Club Tech Director '80 Carousel Red Turbo T/A, 26k orig. '79 "Y89" 400/4 speed 10th Ann. T/A, 57k orig '84 Olds 88 Royale Bgm 2 dr, 307 "Rocket" (lol), 141k and still going.... '80 T/A project car...
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long but worth the advice Okay you replace your exhaust. You notice a rattle at the same time you lose a noticable amount of power. You probably Got on your car right after the replacement to really enjoy the new sound, thus forcing more pressure into the stock cats, that alone could have caused the problem along with getting the old exhaust off can also require the assistance of a hammer. YOUR PROBLEM IS THIS.... Given one of the circumstances I just mentioned or both, the inside of your cat has become either loose or begun to crumble therefore causing the rattle youre hearing and since it is not a straight flow now you're getting significant backpressure to whatever side is blocked. You should change both cats so that there is even milage on both cats. Not changing it will cause massive heat build up to the head on the side that is cloged and possibly damge that as well. Take your car for a ride durring night time for 15-25 minutes then look under the car right after. if your clog i severe enough then one if not both of your cats will glow orange
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Get rid of the converters,,,,,,,,
lOn 15 Nov 2003 14:44:46 -0800, snipped-for-privacy@charter.net (MinnesotaFirebird) wrote:

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Depends where you live and your use for the car... wish it was that easy to do.
On Thu, 27 Nov 2003 03:26:10 GMT, DOXIE WALLSzzz

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Accomplishes nothing except telling this group how stupid you are.
You can get high-flow converters that will flow as good or BETTER than if you removed the converters alone.
With that being said, sounds like you drive a POS because you wouldn't know what to do with a good F body.
Bottom line: Emission controls are removed out of ignorance, not performance upgrades.
Joe--ASE Certified Parts Specialist & 10th Ann.Club Tech Director '80 Carousel Red Turbo T/A, 26k orig. '79 "Y89" 400/4 speed 10th Ann. T/A, 57k orig '84 Olds 88 Royale Bgm 2 dr, 307 "Rocket" (lol), 141k and still going.... '80 T/A project car...
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this post is one of the best put posts Ive seen to date. People just dont understand that these motors were designed to run with converters and all emissions equip'.... Putting better flowing aftermarket parts on it, will help flow and add some power but to remove them completely, now your working in reverse. The engines are designed to build power with the emissions equipment. Up gradeit dont remove it
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