Headers And Ory Installed.. Major Problems!!!
Thread Starter
Staging Lane
Joined: Sep 2005
Posts: 83
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Headers And Ory Installed.. Major Problems!!! I had the loudmouth modular catback put on over a year ago and loved the sound. I've since put on my pacesetter lts and a texas speed ory, but the car was ridiculously loud and raspy with the loudmouth resonator so I put a magnaflow straight through muffler on it which has quieted it down a bit but it still really raspy especially when downshifting. Another thing I noticed is that I seemed to have lost alot of low end power. A couple of guys at my job said that by getting rid of the cats and having no restrictions, you lose backpressure and low end power as well as having alot of drone/rasp. I'm also noticing that when I step on the gas and let off around 2500 rpm there's like a coughing/crunching sound underneath the car which wasn't present before. I had all the work done at an exhaust shop, and from underneath there doesn't appear to be any leaks. I'm almost ready to put some cats on there cuz the car is running and sounding like sh*t. An ASE master certified mechanic also told me that the rear O2 sensors do more than just tell the PCM that the cats are working which is contrary to what people have said on here.. They are both responsible for monitoring air fuel ratios and adjusting long term fuel trims, which makes sense because my car is also running very poorly since removing the rear O2s.. Any advice you guys could give me would be appreciated.. thanks..
Well, the ASE Master Certified Garunteed Super Duper Mechanic is wrong on this one. 
I'd bet money the lack of power is either due to something not buttoned up right (ie plugs, wires, loose ground, etc.), your AFR being off, or knock retard. I had a stock-internals motor running through a free-flowing set of 3" true duals (even less backpressure than your system) and when I switched to a Magnaflow catback, it slowed down some. Your torque curve might move around a little, but I have yet to see any physical proof of less backpressure equaling a slower car. Even my buddies big-block T/A runs better with open headers at the track.
Chances are, you're running too lean and possibly causing some knock. Then, the knock sensors are picking up the pinging sound and pulling timing. Get your car tuned for your setup or better yet, buy some software & a WBO2 and tune it yourself. Then, tell your mechanic how wrong he was about the stock rear O2's contribution to the LTFT's.
I'd bet money the lack of power is either due to something not buttoned up right (ie plugs, wires, loose ground, etc.), your AFR being off, or knock retard. I had a stock-internals motor running through a free-flowing set of 3" true duals (even less backpressure than your system) and when I switched to a Magnaflow catback, it slowed down some. Your torque curve might move around a little, but I have yet to see any physical proof of less backpressure equaling a slower car. Even my buddies big-block T/A runs better with open headers at the track.
Chances are, you're running too lean and possibly causing some knock. Then, the knock sensors are picking up the pinging sound and pulling timing. Get your car tuned for your setup or better yet, buy some software & a WBO2 and tune it yourself. Then, tell your mechanic how wrong he was about the stock rear O2's contribution to the LTFT's.
Last edited by SSpdDmon; Mar 5, 2007 at 07:24 PM.
I agree, the mechanic is wrong. Now I would give it a few days, about 200-250 miles for the computer to relearn itself before you get worried. Although I would check for loose connections and stuff.
Thread Starter
Staging Lane
Joined: Sep 2005
Posts: 83
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Originally Posted by 11SECSS
Did you install some 02 sims or have your rear 02's deleted from your PCM. If you just put them back into the ORY pipe then that be your problem.
Thread Starter
Staging Lane
Joined: Sep 2005
Posts: 83
Likes: 0
Originally Posted by SSpdDmon
Well, the ASE Master Certified Garunteed Super Duper Mechanic is wrong on this one.
I'd bet money the lack of power is either due to something not buttoned up right (ie plugs, wires, loose ground, etc.), your AFR being off, or knock retard. I had a stock-internals motor running through a free-flowing set of 3" true duals (even less backpressure than your system) and when I switched to a Magnaflow catback, it slowed down some. Your torque curve might move around a little, but I have yet to see any physical proof of less backpressure equaling a slower car. Even my buddies big-block T/A runs better with open headers at the track.
Chances are, you're running too lean and possibly causing some knock. Then, the knock sensors are picking up the pinging sound and pulling timing. Get your car tuned for your setup or better yet, buy some software & a WBO2 and tune it yourself. Then, tell your mechanic how wrong he was about the stock rear O2's contribution to the LTFT's.
I'd bet money the lack of power is either due to something not buttoned up right (ie plugs, wires, loose ground, etc.), your AFR being off, or knock retard. I had a stock-internals motor running through a free-flowing set of 3" true duals (even less backpressure than your system) and when I switched to a Magnaflow catback, it slowed down some. Your torque curve might move around a little, but I have yet to see any physical proof of less backpressure equaling a slower car. Even my buddies big-block T/A runs better with open headers at the track.
Chances are, you're running too lean and possibly causing some knock. Then, the knock sensors are picking up the pinging sound and pulling timing. Get your car tuned for your setup or better yet, buy some software & a WBO2 and tune it yourself. Then, tell your mechanic how wrong he was about the stock rear O2's contribution to the LTFT's.
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If the y is hitting the floor board then that is your problem. It is setting your knock sensor. I had the same proplem with a pos ory pipe. I just put on the duals and I thought I stole someones car. The knock sensors are very sensitive.
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12 Second Club
Joined: Jul 2006
Posts: 799
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From: Pittsburgh,PA
thats strange that it feels like you lost low end power. i have to agree with you on the loudmouth bein too loud and raspy but if it bothers you that much, i'd get a diff exhaust. thats what im doin...
the y pipe hitting the floor is really annoying...i need to do somethin about that too
the y pipe hitting the floor is really annoying...i need to do somethin about that too
Originally Posted by RiceEatingWS6
I just got rid of the rear O2s since theres no place to put them with the ORY setup.
You either need to get the rear O2s tuned out or get simms. I bet thats your problem there.
Thread Starter
Staging Lane
Joined: Sep 2005
Posts: 83
Likes: 0
Originally Posted by Studytime
polyurethane mounts for the win...
Ben T.
Ben T.
Thread Starter
Staging Lane
Joined: Sep 2005
Posts: 83
Likes: 0
Originally Posted by 00slowredz
thats strange that it feels like you lost low end power. i have to agree with you on the loudmouth bein too loud and raspy but if it bothers you that much, i'd get a diff exhaust. thats what im doin...
the y pipe hitting the floor is really annoying...i need to do somethin about that too
the y pipe hitting the floor is really annoying...i need to do somethin about that too
