Headers And Ory Installed.. Major Problems!!!
03-05-2007, 05:58 PM
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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..
03-05-2007, 06:17 PM
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Losing noticeable low end power without cats is a myth. Saying that there doesnt appear to be a leak is pretty far from scientific. Do you hear any ticking? Did you use quality band clamps? What year is the car? Did you also remove the AIR system? Did the shop use new plugs and install them AFTER the headers? Doing a search over these topics can give you a good place to start. It could be a ton of stuff....thats why its always best to go to a reputable shop or do the work yourself.
03-06-2007, 12:21 PM
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When you remove the rear 02 sensors, you have to have the codes removed from the computer or run sims, I'm assuming you did that. You then have to drive it a while for the computer to "relearn" the settings.
During low rpms or decel, you might be hearing the exhaust backfiring. If you hear popping and crackling that is it. That is normal when you remove the cats. Means you are running a bit rich. Nothing dangerous but a tune would cure that.
You could weld in a real muffler in place of your resonator. That would quiet it down a bit, and also remove some of the rasp you have.
During low rpms or decel, you might be hearing the exhaust backfiring. If you hear popping and crackling that is it. That is normal when you remove the cats. Means you are running a bit rich. Nothing dangerous but a tune would cure that.
You could weld in a real muffler in place of your resonator. That would quiet it down a bit, and also remove some of the rasp you have.
03-16-2007, 10:16 PM
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Originally Posted by lsx24
When you remove the rear 02 sensors, you have to have the codes removed from the computer or run sims, I'm assuming you did that. You then have to drive it a while for the computer to "relearn" the settings.
During low rpms or decel, you might be hearing the exhaust backfiring. If you hear popping and crackling that is it. That is normal when you remove the cats. Means you are running a bit rich. Nothing dangerous but a tune would cure that.
You could weld in a real muffler in place of your resonator. That would quiet it down a bit, and also remove some of the rasp you have.
During low rpms or decel, you might be hearing the exhaust backfiring. If you hear popping and crackling that is it. That is normal when you remove the cats. Means you are running a bit rich. Nothing dangerous but a tune would cure that.
You could weld in a real muffler in place of your resonator. That would quiet it down a bit, and also remove some of the rasp you have.
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03-19-2007, 09:16 AM
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Originally Posted by RiceEatingWS6
I had them removed but haven't had it tuned yet to remove the codes, I also haven't had time to entirely remove the AIR system I just pulled the relay so it wouldn't turn on. Will not having the codes tuned out cause it to run poorly? I put a straight through magnaflow muffler in place of the resonator and it is quieter, but still super raspy and full of drone around 2500k and when downshifting..
ORY is inherently raspy, that is the nature of the beast. What kind of straight through muffler from Magnaflow did you put on there? The larger the better. If it's a bullet type muffler, it prob won't cure the rasp very much.
I would get the car on a dyno. Then you will see the hp curve, and what your air/fuel ratio really is. Should be about $65 for a couple of pulls. That will tell alot.
To cure rasp, you can either 1) get a full size magnaflow catback, or 2) weld some cats onto your ypipe.
On a small chance, you could have more codes that are being thrown. You could get a code reader, or have the 02 codes tuned out and see what's left. That will help diagnose the performance problem.
