Knocking out the CAT's
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Joined: May 2003
Posts: 116
From: Seymour Johnson AFB, NC
Knocking out the CAT's
I am curious to what drawbacks could occur from replacing my cat's with just a straight pipe.. or just knocking the stuffing out of them. I know it's not the leagle thing to do.. or anything like that.. but I know alot of people who have done them and alot say yeah.. and some say they lost power. I have also heard that the O2 could give a permanent "Lean Reading" due to way to much airflow. I'm just curious to what side effects that I might encounter if I decide to do this or I might just go with a high flow cat.... does anyone know where to get those cheap? Thanks for the help. Also by the way I am running BBK shorty headders and a SLP Loudmouth exhaust if any of that makes a difference.
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Joined: May 2000
Posts: 406
From: Haverhill MA
I for one wish I didnt hollow out my cat. There is no differance to me, except its more annoying/loud. I didnt see any performace gain at all. You have duel cats ? If you change your mind later it will cost you a few bills to buy a dual cat setup. Just my 2 cents.
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Joined: Dec 1999
Posts: 825
From: Houston, TX
You will pick up a few horsepower if you gut the cats, but not very much. The reason you hear people say they lost power is because often times the power curve shifts, in other words you might lose a small amount of low end torque, but will make up for it with a few more hp in the top end. As for the O2's giving a permanent lean reading, I've never heard of that. Gutting the cats will have no effect on the front O2 sensor readings, but you will have to get O2 sims for the rear O2 sensors.
Aside from having to get O2 sims, you may run into the OBDII backpressure problem. By gutting the cats, often times the exhaust doesn't provide enough backpressure for the EGR to function properly, as a result you'll get an SES light for the EGR.
Overall, I'd say it's not worth it. You'd have to spend $90 on some O2 sims and run the risk of the EGR problem, all this for ~5 hp.
Just my .02
Aside from having to get O2 sims, you may run into the OBDII backpressure problem. By gutting the cats, often times the exhaust doesn't provide enough backpressure for the EGR to function properly, as a result you'll get an SES light for the EGR.
Overall, I'd say it's not worth it. You'd have to spend $90 on some O2 sims and run the risk of the EGR problem, all this for ~5 hp.
Just my .02
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Joined: May 2003
Posts: 116
From: Seymour Johnson AFB, NC
Thanks for all of the advice... once again proving it is better to ask before doing! Thanks again!
One last question.. would free flow cats help outand still give me back pressure.. they are just so expensive!
One last question.. would free flow cats help outand still give me back pressure.. they are just so expensive!
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