hw3__

I wanted to upgrade my stock NPP exhaust on my A6 GS so i purchased the Corsa Extreme... but come to find out my 2012 GS has 4 CATs (the 2 original CATs + 2 additional CATs attached to the X-PIPE)

Starting with my 4 CATd stock 2012 exhaust i had a quick install performed to upgrade to the axle-back Corsa Extreme and the sound is nowhere near as LOUD as i thought it would be enhanced to!!!

HELP!!! are those 2nd set of CATs on the stock X-PIPE my problem???

Thanks in advance for the help!

CATd X-Pipe


non-CATd Corsa X-Pipe


Stock CATd vs Corsa X-Pipe



Primary CATs Bolt-On

speedraider

leave them alone if you like the warrantee

Red Devil

If you are looking for volume you'd be best to go full exhaust using hiflow cats. You can also look at installing some headers for extra power and volume.

JCtx

Before anything else, exhaust changed in 2009, so scratch 2008. I have a 2011 X-pipe I bought from Jeremy Formato sitting in my house, but will wait for the swap when I change engine oil and all other fluids at the 3K-mile mark, since I'll have to put the car on the air in ramps and jack stands, and it's not an easy task. Jeremy said he put both on top of each other, and they're identical. However, it's possible the flanges are different (he hasn't reply to that message yet). I could still bolt it up, but would have to use bolts and nuts instead of the studs on the X-pipe. The spot-welded clamps at the rear look identical, so no issues there. The picture I saw was from a Z06, so it might be different. I won't know until I get under there, and scrutinize everything before touching my stock pipes. If everything is identical, I'd definitely do it. I could bet cash money 1 out of 20 dealers wouldn't even notice and/or know the difference. But if I have to use Home Depot bolts and nuts, it's not going to look OEM, and therefore, might sell the X-pipe and leave it alone. I want it to look 100% OEM. I'll report here if nobody else has done it when I get to do the swap. And more than volume and restriction, I'm doing it for the freaking extra heat those cats spew. And losing a few pounds wouldn't be bad either .

SDatl404

Does the exhaust in the 2012s rob power over the earlier years or does it just cause the car to be quieter?

hw3__

spoke with my local chevy dealer where i made purchase and they stated that anything CAT BACKWARDs is fine and will keep warranty intact

this setup is what i gradually want to migrate to when i find the urge to move to the dark side and get rid of my warranty.

thanks for the info... i will stay tuned!

i can't speak off of experience as i have not have my car dyno'd yet but i haven't heard any power reductions on the 2012 exhausts. i plan to get it dyno'd soon so i will try to revisit your question when i have facts.

as far as quieter YESSS because there are the 2 original CATs followed by 2 additional CATs located at the start of the X-PIPE which muffles the sound x4 instead of the original x2.

inner3

So to have a couple of the cats removed would add more sound and possibly relieve the exhaust?

MarkRx

sorry to bust your bubble, but even if you buy a pre-2012 x-pipe, it won't fit. the flange to the primary cat pipe is backwards. you have to replace the cats, at least on the 2012 Z06. here's a pic of a 2011 vs 2012 z06/zr1 x-pipe:

ScottJ03

Corsa X-pipe on 2012 GS CE A6 works. No problem. Z06 may be different.

kevakasper

Are they cats or resonators? No O2 bungs after, so did you look down the pipe for honeycomb? What would be the reason for additional cats down stream of the primary if they don't have any O2 info for the computer? seems like additionl unnecessary weight which they avoid like the plague. My Corsa touring system puts resonators in that exact spot.

KneeDragr

Wow that sucks.

MarkRx

interesting that the corsa fits, maybe it's just on the the 2.5" system. here's the cats in the 2012 z06 x-pipe. this design looks like the inlets on the donaldson powercore air filter. looks pretty high flow and yes it's post O2, why did you do this GM?

All2Easy

Yep, they are cats....no bungs afterward.

I have a Corsa X Pipe but have not installed it. I imagine it would make the system a little louder with it since you would be eliminating these two extra cats.

However, only concern I would have is that a dealership could claim you are messing with the emissions system since the stock X pipe does indeed include these two cats, and possibly deny your warranty. However, I am not speaking from experience on this point.

Richie Fazio

I'm pretty surprised that the corsa extreme isn't loud enough for you. I've heard it and think its really loud. Maybe you need another exhaust then if its not loud enough?

hw3__

same thing i said after i got my new vacuum cleaner!

thanks Scott... yeah i ordered the Corsa X-Pipe yesterday from WCC so we shall see if i get that volume upgrade (fingers crossed)

its not that per say... i actually witnessed both the sport and extreme in action and decided to go with the extreme because of its volume output. the setback in my endeavor is that i was unaware the 2012+ C6s have those 2ndary set of CATs on the stock x-pipe which i hope is what is causing the extreme system to be so much more muffled!!! even quieter than the stock NPP!!!

i can only speak for my case (you may want to call your local dealer and verify as well)... but i spoke to dealership while i was in search of the 2011 x-pipe part # and just happen to ask if i were to replace the stock x-pipe on my 2012 with the 2011 x-pipe would this have any affect on my warranty and he said NO... anything CAT BACKWARDs is fine!

haha i felt like i was on Wheel of Fortune when i first saw the CATd stock x-pipe.... VANNA can i get a YYYYYYYY!!!!!
so Mark in your discoveries that the flanges are diff for the Z x-pipes what is gonna be your next plan of action on your exhaust? ...btw what exhaust are you upgrading to?

SDatl404

What I am curious about is if changing the x-pipe on a 2012 makes a big difference in power...

Seeing as the the computer doesn't monitor these extra cats it shouldn't throw any lights on.

All2Easy

hw3-
I hear what you are saying, but the x-pipe does include cats. So it's really a matter of interpretation. Your dealer is saying cat backwards is fine. Does he indeed mean only the cats in the headers, or is he including these in his assessment?

Just be sure, that's all I am saying. And get it in writing if possible.....a service guy there today may not be there when you need something actually done.

MarkRx

my intents were to leave the car stock until i saw the cats in the new x pipe.... i have an oem zr1 x pipe hanging in the garage. so i jacked up the car and looked underneath figured it would be a plug and play. nope... i had to get some zr1 cat pipes and change those out, not only is the flange different, the length is different also. there's a thread in the z06 forums. so now the car is as loud as my 07Z was with the zr1 x-pipe and zr1 mufflers. the 2nd set of cats do tame it down just a touch, but still nothing like a stock 06-10 Z06.

hw3__

i totally get where you are coming from and thanks for the advice... NOTED!

i see... so on your 2012 Z you just upgraded from the primary CATs backwards or did you replace ALL CATS? with earlier year zr1 x-pipe and zr1 mufflers to achieve that sound upgrade you were looking for? direct bolt on???

could you paste the link to the aforementioned thread...

Richie Fazio

its not that per say... i actually witnessed both the sport and extreme in action and decided to go with the extreme because of its volume output. the setback in my endeavor is that i was unaware the 2012+ C6s have those 2ndary set of CATs on the stock x-pipe which i hope is what is causing the extreme system to be so much more muffled!!! even quieter than the stock NPP!!!


Sounds like that is the problem. I have corsa sport on my 09 and it is much louder then stock NPP. corsa extreme is even louder then my sport, so it has to be the changes that they made to the 2012+.