Npp
Thread Starter
Pro
Joined: Nov 2012
Posts: 585
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From: FL
Thank you. However, I'm not talking about the flapper valves in the mufflers. The NPP exhaust I received from the salvage yard revealed a honey cone baffle in the inlet side of the exhaust pipe on the right (passenger) side, the left (drivers) side was open. I'm looking to confirm that GM in fact does installed this honey cone baffle.
My car runs and sounds just like my previous '10 GS that had the NPP option, Thanks again.
My car runs and sounds just like my previous '10 GS that had the NPP option, Thanks again.
thing knower
Joined: Mar 2017
Posts: 3,404
Likes: 942
From: wpb
Thread Starter
Pro
Joined: Nov 2012
Posts: 585
Likes: 39
From: FL
Yes, that's what it looked like - but it was in the right exhaust pipe before the axle - maybe it had broken loose from the CAT on the previous car. I did poke around at it with a screwdriver but didn't know if it should be there or not so I left it alone and then I forgot about mentioning it to my shop prior to installation. Like I mentioned I don't hear or notice any performance difference from the NPP optionI had on '10 GS. However, now knowing from your post above I wished I had of dug it out of the pipe before installation. Thank you for your reply.
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Melting Slicks
Joined: Apr 2002
Posts: 2,397
Likes: 55
From: Dove Mountain, AZ
Who ever had the car probably tried to remove it from the mid pipe and pushed it back into the pipe and it worked its way back.
I would get it out, it might get sideways and block the flow. The problem is, they are made of metal not ceramic and can be a pain to get out.. (I have been told)
I would get it out, it might get sideways and block the flow. The problem is, they are made of metal not ceramic and can be a pain to get out.. (I have been told)
Last edited by TXSTICK; Jul 14, 2021 at 09:15 AM.
thing knower
Joined: Mar 2017
Posts: 3,404
Likes: 942
From: wpb
thats where i got the little trophy in my pic... my buddy thought his motor was dying, so i hit each cat with a rubber mallet... found the rattle, cut, extract, reweld....
Thread Starter
Pro
Joined: Nov 2012
Posts: 585
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From: FL
I agree about trying to get it out - my baffle piece is six inched deep inside the right axle back pipe (left side was clear) and did not budge when poking at it with a screwdriver so I just left it alone. My thought at the time was that it is a factory GM installed baffle and is supposed to be there. In any event after some spirited driving it's probably packed in there a little tighter now.
thing knower
Joined: Mar 2017
Posts: 3,404
Likes: 942
From: wpb
I agree about trying to get it out - my baffle piece is six inched deep inside the right axle back pipe (left side was clear) and did not budge when poking at it with a screwdriver so I just left it alone. My thought at the time was that it is a factory GM installed baffle and is supposed to be there. In any event after some spirited driving it's probably packed in there a little tighter now.
ahh, it will probably wind up working its way to the muffler and rattle, if its stuck in place NOW.... its a really great time to take the effort to remove it....
even busting it in half will release it and you can pull it out.... catalytic material is very fragile, so its not going to take too much effort to break up if you can still see it with your eyes (not a borescope)...
CAN you leave it? sure.... is it a good idea? depends... if it eventually winds up jarring loose, its going to end up in the muffler....
its also forcing exhaust gas to flow out one muffler instead of both (well more on one side at least)... so one will wind up "sootier" than the other... also, there's a performance hit as you are effectively restricting exhaust gas flow from the motor... (remember the motor is just an air pump... air in... air out)...
personally, i would make the effort to get it broken up and removed.... at least now you know what it is....
Last edited by drewz06; Jul 14, 2021 at 10:03 AM.