How much does taking off the catalytic converter help?? Also do you get a bunch of things like check engine and other problem lights that come on???

 

Here's my own personal experiences with this subject. I removed my cat during replacing the Y pipe for my headers. Just for laughs I had a test pipe made up to see what would happen. The exhaust sound is great. Deep and louder than before,almost like an LT1 with a Flowmaster. Performance improved as well. So much that I've been running without the cat since September of this year. When my yearly inspection comes up(March)I'll put a new one on for the test and take it back off the rest of the time. As for SES lights,I've always had the occassional light for code 32/EGR failure. This is due to lower than normal backpressure. TBI cars have always had this problem. As long as the car doesn't act different you have no problem.


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Mongoose-NCTGA-1990 Pontiac Formula/305 TBI-700R4 with Edelbrock Performer TBI intake,TES headers,and STB,K&N,MSD-6AL,Holley laser shot coil,Accel Extreme 9000 wires,Jet Stage 2 chip,TCI shift kit with corvette servo,Richmond 3.73 gear with Auburn 3 series posi,no cat,SLP 3" cat back,Eibach sportline springs,Energy Suspension poly throughout,Lakewood LCA and adjustable panhard bar package,SSM subframe connectors,IROC wonder bar,Tokico 5 way adjustable struts and shocks,Autometer electric fuel pressure gauge,Alpine,JL Audio,MB Quart,92 GTA taillights,92 GTA aero wing and hatch,Steve Spohn LCA relocater kit,MacEwen White face gauges,84 T/A cold air induction air cleaner.

 

I yanked my cat when I did my headers and just put a straight 3" pipe in its place. Loved the sound and the performance at the higher RPM's but I noticed a slight loss in torque in the bottom RPM's. Has to do something with backpressure I guess.

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Eric Natzke
91 Firebird 305 TBI (ZZ5 summer of "01")
ASCD Ram Air Hood-3" custom exaust-Flowmaster 80 Series-No Cat-Edelbrock TES Headers (coated)-March Pulleys-TBI Spacer-K&N Open ELement-TransGo Shift Kit-B&M Supercooler 28,000 GVW-Hypertech Thermomaster-160 Stat-3:42 GM Gears-Auburn Posi Unit-Edlebrock Strut Tower Brace-MSD Superconducters-MSD Cap & Rotor-MSD Blaster Coil-Rapidfire Plugs-265/50/R15 Tires-Emmison's all Gone
http://members.aol.com/j007golden/91firebird.html
For info on certain parts or mods go to the site below
http://members.aol.com/j007golden/modeval.html

 

I gutted my cat, I don't get any codes at all, and I gained Torque. I reccomend it.

 

Hey Magyver, what size exaust do u have?

Here is a link to a discussion about removing that cat.
https://www.thirdgen.org/messgboard/...ML/000430.html

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Eric Natzke
91 Firebird 305 TBI (ZZ5 summer of "01")
ASCD Ram Air Hood-3" custom exaust-Flowmaster 80 Series-No Cat-Edelbrock TES Headers (coated)-March Pulleys-TBI Spacer-K&N Open ELement-TransGo Shift Kit-B&M Supercooler 28,000 GVW-Hypertech Thermomaster-160 Stat-3:42 GM Gears-Auburn Posi Unit-Edlebrock Strut Tower Brace-MSD Superconducters-MSD Cap & Rotor-MSD Blaster Coil-Rapidfire Plugs-265/50/R15 Tires-Emmison's all Gone
http://members.aol.com/j007golden/91firebird.html
For info on certain parts or mods go to the site below
http://members.aol.com/j007golden/modeval.html

[This message has been edited by 91Bird305 (edited December 02, 2000).]