Exhaust Question and Cat vs. No Cat
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From: St. John's
Exhaust Question and Cat vs. No Cat
Alright heres the deal some people might remember my help thread with the stage 3 installation, got that all taken care of thanks for the help people. 
Now since I've been having fun with the newfound power my exhaust started to sound terrible, at first it was just a little rattle that started going WOT on the highway in 3rd, thought it was the belt assembly at first but everything is perfect so I moved onto the exhaust. It rattles kinda when the car is under load but not yet into boost, well I guess it does it when its in boost as well but I cant hear it because of the supercharger whine. Anyway I have a bad mab header, stock DP and borla catback, first I started with the header all bolts are tight and torqued to spec, looked under the car with it going no sign of exhaust leak but there is kind of a rattling metal on metal noise at idle before the car is warmed up coming from the cat. I'm pretty sure its coming from the cat anyway and as well when I stop the car I can smell like exhaust but it smells like its mixed with burnt rubber or some other bad smell. So I searched the forums and it said if the cat was bad it should be boosting more but I'm right around 15 to 16 PSI which is where I assume I should be with a 2.9 pulley. So to the people with experience does this sound like a toasted cat? And if it is a toasted cat, I'm not sure what to do, so does catless really sound that bad that I should go with a hi flow cat? or am I just better off with no cat. I have the GM stage 3 computer which I believe has the rear O2 delete so I shouldent throw any codes catless, thanks for the help again
Now since I've been having fun with the newfound power my exhaust started to sound terrible, at first it was just a little rattle that started going WOT on the highway in 3rd, thought it was the belt assembly at first but everything is perfect so I moved onto the exhaust. It rattles kinda when the car is under load but not yet into boost, well I guess it does it when its in boost as well but I cant hear it because of the supercharger whine. Anyway I have a bad mab header, stock DP and borla catback, first I started with the header all bolts are tight and torqued to spec, looked under the car with it going no sign of exhaust leak but there is kind of a rattling metal on metal noise at idle before the car is warmed up coming from the cat. I'm pretty sure its coming from the cat anyway and as well when I stop the car I can smell like exhaust but it smells like its mixed with burnt rubber or some other bad smell. So I searched the forums and it said if the cat was bad it should be boosting more but I'm right around 15 to 16 PSI which is where I assume I should be with a 2.9 pulley. So to the people with experience does this sound like a toasted cat? And if it is a toasted cat, I'm not sure what to do, so does catless really sound that bad that I should go with a hi flow cat? or am I just better off with no cat. I have the GM stage 3 computer which I believe has the rear O2 delete so I shouldent throw any codes catless, thanks for the help again
If you think this sounds like crap..get a cat..personally I like my exhaust setup an it cost 1/5th of what most ppl pay to make their cars sound "good"
Stage WTF Cobalt SS/SC Flyby - YouTube
Stage WTF Cobalt SS/SC Flyby - YouTube
mine was wore out so figured I would take it off to see what it sounded like and wala lol
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