Recall (Catalytic Converters/H Pipe)
09-21-2015, 02:16 PM
#22
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2012 and 2013 came stock with 4 cats. Two monitored and two unmonitored...I promptly removed the extra two unmonitored cats...( live in Texas)...
The HP rating for 2012/2013 were the same as previous years with only two cats, so I am guessing they tuned the car more aggressively to accommodate for the two extra green tree hugger restrictions...Perhaps they are just sticking you guys with the same tune....
Hmmm...my understanding of catalytic converters is that they typically last the life of the car, and if they are clogged or running below standard your ECU/ECM would throw a code up...so the probability is no one had a bad cat. The performance gain is either seat of pants/placebo ( like a intake) or GM is tuning the car more aggressively to accommodate for the restrictions. The driver than thinks due to these changes that his car has improved...again also placebo....or maybe I am wrong the tune is actually an improvement. But bad cats vs good cats and an improvement?...low probability of that... so dont send em any candy.
The HP rating for 2012/2013 were the same as previous years with only two cats, so I am guessing they tuned the car more aggressively to accommodate for the two extra green tree hugger restrictions...Perhaps they are just sticking you guys with the same tune....
Hmmm...my understanding of catalytic converters is that they typically last the life of the car, and if they are clogged or running below standard your ECU/ECM would throw a code up...so the probability is no one had a bad cat. The performance gain is either seat of pants/placebo ( like a intake) or GM is tuning the car more aggressively to accommodate for the restrictions. The driver than thinks due to these changes that his car has improved...again also placebo....or maybe I am wrong the tune is actually an improvement. But bad cats vs good cats and an improvement?...low probability of that... so dont send em any candy.
It's labeled an Emissions recall most likely because the 2 Original Cats were not cleaning the exhaust gases efficiently in combination with the original tune for the 2 Cat setup.
They replace the 2 Original Cats located just off the exhaust manifolds and add 2 "smaller" Cats after them just under the tunnel.
The 2 smaller cats are also now connected to a Different X pipe that is actually an Open flow X pipe unlike the Original X pipe which was 2 separate pipes welded together.
Now the exhaust gases can flow through either side of the pipe leading to the mufflers for less restriction.
The new Tune is done to work with all these new Cats and X pipe.
Whether or not this new setup adds more HP is debatable.
But I can tell you it Certainly does Not reduce the HP or the way the engine runs.
I was in the camp of no way I want to have this recall done,.." my car runs great the way it is".
And for all intent and purposes it did run just fine
But I've put over 2000 miles on since the recall was done and it definitely runs better now, than it did compared to the 1st 23,000 miles before the recall.
It's running a lot leaner and more responsive all the way up through the RPM range.
My exhaust tips have no where near as much soot as they used to have.
I still get on it as much I did before the recall and as I mentioned in post #7, my MPG has increased.
The exhaust note was definitely subdued for about the 1st 500 miles, but its now about 90% of the way it was before the recall.
Anyway , this has been MY experience since having the recall done.
YMMV
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ghellyer (10-17-2015)
09-22-2015, 08:54 PM
#23
Race Director
IMO it's not about "bad" or clogged Catalytic Converters.
It's labeled an Emissions recall most likely because the 2 Original Cats were not cleaning the exhaust gases efficiently in combination with the original tune for the 2 Cat setup.
They replace the 2 Original Cats located just off the exhaust manifolds and add 2 "smaller" Cats after them just under the tunnel.
The 2 smaller cats are also now connected to a Different X pipe that is actually an Open flow X pipe unlike the Original X pipe which was 2 separate pipes welded together.
Now the exhaust gases can flow through either side of the pipe leading to the mufflers for less restriction.
The new Tune is done to work with all these new Cats and X pipe.
Whether or not this new setup adds more HP is debatable.
But I can tell you it Certainly does Not reduce the HP or the way the engine runs.
I was in the camp of no way I want to have this recall done,.." my car runs great the way it is".
And for all intent and purposes it did run just fine
But I've put over 2000 miles on since the recall was done and it definitely runs better now, than it did compared to the 1st 23,000 miles before the recall.
It's running a lot leaner and more responsive all the way up through the RPM range.
My exhaust tips have no where near as much soot as they used to have.
I still get on it as much I did before the recall and as I mentioned in post #7, my MPG has increased.
The exhaust note was definitely subdued for about the 1st 500 miles, but its now about 90% of the way it was before the recall.
Anyway , this has been MY experience since having the recall done.
YMMV
It's labeled an Emissions recall most likely because the 2 Original Cats were not cleaning the exhaust gases efficiently in combination with the original tune for the 2 Cat setup.
They replace the 2 Original Cats located just off the exhaust manifolds and add 2 "smaller" Cats after them just under the tunnel.
The 2 smaller cats are also now connected to a Different X pipe that is actually an Open flow X pipe unlike the Original X pipe which was 2 separate pipes welded together.
Now the exhaust gases can flow through either side of the pipe leading to the mufflers for less restriction.
The new Tune is done to work with all these new Cats and X pipe.
Whether or not this new setup adds more HP is debatable.
But I can tell you it Certainly does Not reduce the HP or the way the engine runs.
I was in the camp of no way I want to have this recall done,.." my car runs great the way it is".
And for all intent and purposes it did run just fine
But I've put over 2000 miles on since the recall was done and it definitely runs better now, than it did compared to the 1st 23,000 miles before the recall.
It's running a lot leaner and more responsive all the way up through the RPM range.
My exhaust tips have no where near as much soot as they used to have.
I still get on it as much I did before the recall and as I mentioned in post #7, my MPG has increased.
The exhaust note was definitely subdued for about the 1st 500 miles, but its now about 90% of the way it was before the recall.
Anyway , this has been MY experience since having the recall done.
YMMV
Good to hear!
Thanks for the write up.
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Dif (09-22-2015)
09-22-2015, 09:02 PM
#24
Racer
09-22-2015, 09:05 PM
#25
Racer
My previous post
I just noticed my previous post did not list all the part numbers. 2008 intermediate part number was missing.
Part Number Description Quantity/Vehicle
25958404 Pipe, Catalytic Converter (Left) 1
25958405 Pipe, Catalytic Converter (Right) 1
23331680 Pipe (Underbody Converters, 2008 Only) 1
25958410 Pipe (Underbody Converters, 2009 Only) 1
21992620 Gasket, Exhaust Manifold Pipe 2
12555555 Seal, Exhaust Manifold Pipe 2
Part Number Description Quantity/Vehicle
25958404 Pipe, Catalytic Converter (Left) 1
25958405 Pipe, Catalytic Converter (Right) 1
23331680 Pipe (Underbody Converters, 2008 Only) 1
25958410 Pipe (Underbody Converters, 2009 Only) 1
21992620 Gasket, Exhaust Manifold Pipe 2
12555555 Seal, Exhaust Manifold Pipe 2
09-22-2015, 09:48 PM
#27
Instructor
IMO it's not about "bad" or clogged Catalytic Converters.
It's labeled an Emissions recall most likely because the 2 Original Cats were not cleaning the exhaust gases efficiently in combination with the original tune for the 2 Cat setup.
They replace the 2 Original Cats located just off the exhaust manifolds and add 2 "smaller" Cats after them just under the tunnel.
The 2 smaller cats are also now connected to a Different X pipe that is actually an Open flow X pipe unlike the Original X pipe which was 2 separate pipes welded together.
Now the exhaust gases can flow through either side of the pipe leading to the mufflers for less restriction.
The new Tune is done to work with all these new Cats and X pipe.
Whether or not this new setup adds more HP is debatable.
But I can tell you it Certainly does Not reduce the HP or the way the engine runs.
I was in the camp of no way I want to have this recall done,.." my car runs great the way it is".
And for all intent and purposes it did run just fine
But I've put over 2000 miles on since the recall was done and it definitely runs better now, than it did compared to the 1st 23,000 miles before the recall.
It's running a lot leaner and more responsive all the way up through the RPM range.
My exhaust tips have no where near as much soot as they used to have.
I still get on it as much I did before the recall and as I mentioned in post #7, my MPG has increased.
The exhaust note was definitely subdued for about the 1st 500 miles, but its now about 90% of the way it was before the recall.
Anyway , this has been MY experience since having the recall done.
YMMV
It's labeled an Emissions recall most likely because the 2 Original Cats were not cleaning the exhaust gases efficiently in combination with the original tune for the 2 Cat setup.
They replace the 2 Original Cats located just off the exhaust manifolds and add 2 "smaller" Cats after them just under the tunnel.
The 2 smaller cats are also now connected to a Different X pipe that is actually an Open flow X pipe unlike the Original X pipe which was 2 separate pipes welded together.
Now the exhaust gases can flow through either side of the pipe leading to the mufflers for less restriction.
The new Tune is done to work with all these new Cats and X pipe.
Whether or not this new setup adds more HP is debatable.
But I can tell you it Certainly does Not reduce the HP or the way the engine runs.
I was in the camp of no way I want to have this recall done,.." my car runs great the way it is".
And for all intent and purposes it did run just fine
But I've put over 2000 miles on since the recall was done and it definitely runs better now, than it did compared to the 1st 23,000 miles before the recall.
It's running a lot leaner and more responsive all the way up through the RPM range.
My exhaust tips have no where near as much soot as they used to have.
I still get on it as much I did before the recall and as I mentioned in post #7, my MPG has increased.
The exhaust note was definitely subdued for about the 1st 500 miles, but its now about 90% of the way it was before the recall.
Anyway , this has been MY experience since having the recall done.
YMMV
09-24-2015, 11:13 AM
#28
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Member Since: Mar 2009
Location: Northeast MA & Mad Beach FL
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It runs about 6-10 degrees cooler highway driving and 5-8 degrees cooler in stop and go traffic.
Few weeks ago we were out all day in 99 degree weather.
Before the recall it would run between 210 - 215 in stop and go traffic before getting moving again.
Now it barely reaches 208 and didn't go over 210 all day.
09-24-2015, 05:45 PM
#29
Racer
Member Since: Mar 2013
Location: Cleveland Heights Ohio
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Got my '09 done, the car looks fine underneath and feels great to drive.
Since I got my car when it was 3 years old and through a dealer, I didn't realize that it had a tune done already. First clue was that now the 1-4 skip is back in force... So back to the factory tune- I guess if I want a tune at least I'll be able to decide what it'll be!
Since I got my car when it was 3 years old and through a dealer, I didn't realize that it had a tune done already. First clue was that now the 1-4 skip is back in force... So back to the factory tune- I guess if I want a tune at least I'll be able to decide what it'll be!
09-24-2015, 05:56 PM
#30
Instructor
I just picked up my '08 and, although I didn't have a chance to really open it up, it is definitely running smoother. It's also much quieter, but I'm hoping that will normalize like it did with a previous poster. Two cats, not four, were installed for what it's worth.
09-25-2015, 02:06 AM
#32
Intermediate
08 Cats
Just got my '08 back tonight, 4 cats replaced 2 on exhaust manifold
2 more cats on new mid pipe supplied. Running Corsa Sports,
Will drive more this weekend but definitely reduced the sweet Corsa sound. Some forum members have mentioned after 1000 miles or so, they were back to 90%; will see. "living with California's rules"
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ghellyer (10-17-2015)
09-25-2015, 08:33 AM
#33
Instructor
25958404 - pipe 3.685
25958404 - core return
25958405 - pipe 3.685
25958405 - core return
23331680 - pipe 3.609
23331680 - core return
21992620 - gasket 3.611 (2)
12555555 - seal 3.611 (2)
I've tried locating a description of 23331680, but I can't find any details on that specific part. Any insight?
I did drive the car to work this morning and when I got out, well, let's just say the smell was something less than pleasant.
Can't wait to get these burned in!
09-25-2015, 06:06 PM
#34
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Member Since: Mar 2013
Location: Cleveland Heights Ohio
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I asked the service writer if I now had 2 or 4 and, after looking at the parts list, he thought two. With that said, he didn't seem 100% certain. Here is the parts list from the receipt.
25958404 - pipe 3.685
25958404 - core return
25958405 - pipe 3.685
25958405 - core return
23331680 - pipe 3.609
23331680 - core return
21992620 - gasket 3.611 (2)
12555555 - seal 3.611 (2)
I've tried locating a description of 23331680, but I can't find any details on that specific part. Any insight?
I did drive the car to work this morning and when I got out, well, let's just say the smell was something less than pleasant. Can't wait to get these burned in!
25958404 - pipe 3.685
25958404 - core return
25958405 - pipe 3.685
25958405 - core return
23331680 - pipe 3.609
23331680 - core return
21992620 - gasket 3.611 (2)
12555555 - seal 3.611 (2)
I've tried locating a description of 23331680, but I can't find any details on that specific part. Any insight?
I did drive the car to work this morning and when I got out, well, let's just say the smell was something less than pleasant.
Can't wait to get these burned in!
09-25-2015, 07:25 PM
#36
Instructor
They definitely removed the two old ones and replaced them. It seems that several have confirmed the '09s got four new cats, but there seems to be conflicting information on various threads here about the '08s getting the two existing cats replaced vs getting four new ones. Unfortunately, I don't have a way to get under the car to look. What I can tell you is that it looks like I need to go back to the dealership because of a loose heat shield. 
09-25-2015, 07:37 PM
#37
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I asked the service writer if I now had 2 or 4 and, after looking at the parts list, he thought two. With that said, he didn't seem 100% certain. Here is the parts list from the receipt.
25958404 - pipe 3.685
25958404 - core return
25958405 - pipe 3.685
25958405 - core return
23331680 - pipe 3.609
23331680 - core return
21992620 - gasket 3.611 (2)
12555555 - seal 3.611 (2)
I've tried locating a description of 23331680, but I can't find any details on that specific part. Any insight?
I did drive the car to work this morning and when I got out, well, let's just say the smell was something less than pleasant. Can't wait to get these burned in!
25958404 - pipe 3.685
25958404 - core return
25958405 - pipe 3.685
25958405 - core return
23331680 - pipe 3.609
23331680 - core return
21992620 - gasket 3.611 (2)
12555555 - seal 3.611 (2)
I've tried locating a description of 23331680, but I can't find any details on that specific part. Any insight?
I did drive the car to work this morning and when I got out, well, let's just say the smell was something less than pleasant.
Can't wait to get these burned in!You either have 2 new Cats and a New X pipe.
Or, 4 News Cats and New X pipe.
Anything listed as a "pipe" is a Catalytic Converter ... that is why it's confusing.
Picture is my parts list when they ordered them for my 2009.
If you compare the part #'s, ... 2 part #'s are the same as mine and the one you can't find info on is a * different part #.
25958404 - pipe 3.685 = one of the Original Cats = replaced
25958405 - pipe 3.685 = one of the Original Cats = replaced
* 23331680 - pipe 3.609 = possibly "Only" the new X pipe = replaced
--- On mine, part # 25958410 = a One piece 2 new smaller Cats combination X pipe ..
So if you look under your car and do not see 2 extra Cats in the tunnel area ,... ?
IMO they only replaced your 2 Original Cats and the X pipe, and "maybe" that's why that one part # is different.
Get back to us when you look under your car
09-25-2015, 07:40 PM
#38
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They definitely removed the two old ones and replaced them. It seems that several have confirmed the '09s got four new cats, but there seems to be conflicting information on various threads here about the '08s getting the two existing cats replaced vs getting four new ones. Unfortunately, I don't have a way to get under the car to look. What I can tell you is that it looks like I need to go back to the dealership because of a loose heat shield.
I was typing while you were posting.You can see if there's 2 new Cats or not, in the Tunnel area by laying on the ground and looking under from there
09-25-2015, 11:06 PM
#39
Instructor
09-26-2015, 12:29 AM
#40
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The other 2 that replaced the Original ones are at the rear of the motor.
They hang down (connected) from the rear of the exhaust manifolds.
One on each side