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First time hearing about this and interested
Is this basically a cat delete? Are any codes thrown? Odors?
* Not really a traditional "cat delete" since the 2 MAIN cats (the large cats just aft of the exhaust manifolds) are left in-place and untouched. Only the 2 small, secondary 'pup' cats in the OEM X-pipe are removed when the aftermarket X-pipe is installed.
* Since the 'pup' cats in the C7's X-pipe are unmonitored (no sensors after the pup cats), no codes are thrown -- the car has no idea that they are gone.
* Since the main cats are still in place, no new odors should be noticed.
It is an attractive option, but for some, another reason to avoid it is the possible loss/voiding of the original powertrain warranty. It's a federally-protected piece of emissions hardware, so removing it is NOT the same warranty-neutral action as just replacing the muffler.
Last edited by Kent1999; Jan 24, 2017 at 03:14 PM.
So what would the stock exhaust sound like if we just gutted the 'pup' cats? Change the sound and open the flow appears to be a possibility!
Originally Posted by Kent1999
* Not really a traditional "cat delete" since the 2 MAIN cats (the large cats just aft of the exhaust manifolds) are left in-place and untouched. Only the 2 small, secondary 'pup' cats in the OEM X-pipe are removed when the aftermarket X-pipe is installed.
* Since the 'pup' cats in the C7's X-pipe are unmonitored (no sensors after the pup cats), no codes are thrown -- the car has no idea that they are gone.
* Since the main cats are still in place, no new odors should be noticed.
It is an attractive option, but for some, another reason to avoid it is the possible loss/voiding of the original powertrain warranty. It's a federally-protected piece of emissions hardware, so removing it is NOT the same warranty-neutral action as just replacing the muffler.
* Not really a traditional "cat delete" since the 2 MAIN cats (the large cats just aft of the exhaust manifolds) are left in-place and untouched. Only the 2 small, secondary 'pup' cats in the OEM X-pipe are removed when the aftermarket X-pipe is installed.
* Since the 'pup' cats in the C7's X-pipe are unmonitored (no sensors after the pup cats), no codes are thrown -- the car has no idea that they are gone.
* Since the main cats are still in place, no new odors should be noticed.
It is an attractive option, but for some, another reason to avoid it is the possible loss/voiding of the original powertrain warranty. It's a federally-protected piece of emissions hardware, so removing it is NOT the same warranty-neutral action as just replacing the muffler.
Thanks, was a bit confused as shown in the OP's 2nd pic, the OEM exhaust has an X pipe! It's not adding an X pipe it's removing the smaller secondary CATs as you note.
Found this pic in another post:
OEM exhaust with X pipe and small CATs left, Borla removed CATs and X pipe center (Corsa, double X right.)
SIDEBAR: I added an H pipe to my '88 Vette when installing lower restriction mufflers. It was frankly easier to cut holes in the existing pipes and weld in a small section of pipe between the spaced OEM pipes to make the H. Recall the key issue was where to install the H for max benefit, which could be determined by the temp hot spots in the pipes, not easily done! Looked up the difference and found this article in an old issue of a Super Chevy - here are some clips that may be of interest to some Forum members:
"A balance pipe serves two distinct functions. First off, it takes the left and right banks of an engine’s exhaust and provides a crossover point to equalize flow from side. Secondly, balance pipes smooth out uneven exhaust pulses. Any given engine generates low- and high-pressure exhaust pulses due to the effects of the firing order. As these low and high pulses move downstream through the exhaust piping, they travel at different speeds. Having an exhaust crossover helps draw these pulses out into a more balanced pattern, which ultimately improves engine output. A nice side benefit is that crossovers also decrease in-cabin exhaust drone.
In terms of both performance and price, balance pipes are so effective that GM has been installing them for years on Corvettes and more recently on fifth-gen Camaros.
Generally, the X-pipe will deliver a more high-pitched exhaust note, making a car sound more exotic, whereas an H-pipe gives a deeper tone with more of a traditional hot rod sound,” says George Rumore of Stainless Works. “As for the difference in power gain between the two, it is very minimal. The X-pipe will usually make anywhere from two to four more horsepower than an H-pipe. The slight horsepower difference comes from the way the X-pipe creates a venturi effect, which helps pull the exhaust gases out of the cylinder faster. Overall, the main difference is sound rather than performance, meaning there are no pros or cons. It’s simply a matter of personal preference.”
Thanks, was a bit confused as shown in the OP's 2nd pic, the OEM exhaust has an X pipe! It's not adding an X pipe it's removing the smaller secondary CATs as you note.
Found this pic in another post:
OEM exhaust with X pipe and small CATs left, Borla removed CATs and X pipe center (Corsa, double X right.)
SIDEBAR: I added an H pipe to my '88 Vette when installing lower restriction mufflers. It was frankly easier to cut holes in the existing pipes and weld in a small section of pipe between the spaced OEM pipes to make the H. Recall the key issue was where to install the H for max benefit, which could be determined by the temp hot spots in the pipes, not easily done! Looked up the difference and found this article in an old issue of a Super Chevy - here are some clips that may be of interest to some Forum members:
"A balance pipe serves two distinct functions. First off, it takes the left and right banks of an engine’s exhaust and provides a crossover point to equalize flow from side. Secondly, balance pipes smooth out uneven exhaust pulses. Any given engine generates low- and high-pressure exhaust pulses due to the effects of the firing order. As these low and high pulses move downstream through the exhaust piping, they travel at different speeds. Having an exhaust crossover helps draw these pulses out into a more balanced pattern, which ultimately improves engine output. A nice side benefit is that crossovers also decrease in-cabin exhaust drone.
In terms of both performance and price, balance pipes are so effective that GM has been installing them for years on Corvettes and more recently on fifth-gen Camaros.
Generally, the X-pipe will deliver a more high-pitched exhaust note, making a car sound more exotic, whereas an H-pipe gives a deeper tone with more of a traditional hot rod sound,” says George Rumore of Stainless Works. “As for the difference in power gain between the two, it is very minimal. The X-pipe will usually make anywhere from two to four more horsepower than an H-pipe. The slight horsepower difference comes from the way the X-pipe creates a venturi effect, which helps pull the exhaust gases out of the cylinder faster. Overall, the main difference is sound rather than performance, meaning there are no pros or cons. It’s simply a matter of personal preference.”
so what you are saying, one can just cut the cats out and slide a connector in there and good to go, get the same results with better sound ?
so what you are saying, one can just cut the cats out and slide a connector in there and good to go, get the same results with better sound ?
That is what it looks like to me. Probably 409 stainless like the mufflers so would need the proper size pipe sections and a fixture to keep the flames square.
Does anyone know for sure on the factory warranty? I had a new exhaust planned for my new GS just after the break in period. It included this Borla X Pipe...
Does anyone know for sure on the factory warranty? I had a new exhaust planned for my new GS just after the break in period. It included this Borla X Pipe...
I'm confident in defending mods that I can argue have no effect on engine performance. Would believe you could be successful with a muffler change being acceptable.
However removing the small catalytic converters would not be one I would be comfortable defending! As noted it is not just a different X pipe than the one the OEM exhaust already has as have some prior Vettes. It is the elimination of the secondary catalytic converters. It certainly has an effect on exhaust restriction. Perhaps not as "bad" as headers that do require a reprogram of the fuel/air map but it might be argued by GM it could push it in a lean condition in some conditions.
I'm confident in defending mods that I can argue have no effect on engine performance. Would believe you could be successful with a muffler change being acceptable.
However removing the small catalytic converters would not be one I would be comfortable defending! As noted it is not just a different X pipe than the one the OEM exhaust already has as have some prior Vettes. It is the elimination of the secondary catalytic converters. It certainly has an effect on exhaust restriction. Perhaps not as "bad" as headers that do require a reprogram of the fuel/air map but it might be argued by GM it could push it in a lean condition in some conditions.
Just Sayn'.
I'm pretty confident that GM would feel an illegal powertrain mod would be solid grounds for claim denial on said powertrain, as the owner would be foolish in the extreme to try to take GM to court and ADMIT to a judge, under oath, that he had committed an act prohibited by Federal law, punishable by fines of thousands of dollars.
Warranties don't work the way they're being addressed in this thread. The Moss Magnusson Act, among other protections, protects against unfair denial of warranty claim. The manufacturer, not the owner, must prove that the modification was a direct cause of the failure. These cats, downstrean of the O2 sensors, can do absolutely nothing to damage the motor if removed. Cats are to burn off excess unburned fuel to reduce emissions, the primary ones upstream of the Xpipe are monitored by O2 sensors. There is no way for the manufacturer to link these secondary cats being removed to any causation of powertrain failure in the C7. If a dealer were to tell you anything else, start pushing back. This is a perfectly warranty friendly mod.
Originally Posted by Kent1999
I'm pretty confident that GM would feel an illegal powertrain mod would be solid grounds for claim denial on said powertrain, as the owner would be foolish in the extreme to try to take GM to court and ADMIT to a judge, under oath, that he had committed an act prohibited by Federal law, punishable by fines of thousands of dollars.
Warranties don't work the way they're being addressed in this thread. The Moss Magnusson Act, among other protections, protects against unfair denial of warranty claim. The manufacturer, not the owner, must prove that the modification was a direct cause of the failure. These cats, downstrean of the O2 sensors, can do absolutely nothing to damage the motor if removed. Cats are to burn off excess unburned fuel to reduce emissions, the primary ones upstream of the Xpipe are monitored by O2 sensors. There is no way for the manufacturer to link these secondary cats being removed to any causation of powertrain failure in the C7. If a dealer were to tell you anything else, start pushing back. This is a perfectly warranty friendly mod.
Yes, indeed push back. In theory, what you've described is the way it should work. If it ended there, it would be great. However, the financial and legal realities are far from that simple.
Unfortunately, if GM resists, and decides to block a warranty claim, it takes a lot more than mentioning the magical phrase "Magnuson-Moss!" to get that decision reversed -- often next step would involve threat of legal action to compel GM to perform the warranty service.
GM has taken the stance that it doesn't have to prove direct causation -- it just has to prove that the mod created a non-certified powertrain state. See the literally dozens of threads on aftermarket tunes -- to my knowledge, not ONE of these people have prevailed against GM blocking warranty claims, despite claims that GM has to 'prove' causation. Did GM have to 'prove' the aftermarket tune caused the failure in all those cases? Did any of those plaintiffs prevail?
When you break federal emissions law with a mod, and GM's position is that the illegal mod created a non-certified and illegal powertrain state, thus it is not covered under its warranty, what will your stance be in a court of law? That your vehicle powertrain, that is now in an illegal configuration by your own unlawful acts, should still be required to be repaired under warranty? I would not want to be the one trying to convince a judge of that position.
Again, removing cats is not a legal act, such as replacing a muffler with a non-OEM unit would be (replacing OEM parts with functionally equivalent aftermarket parts *is* protected).
Last edited by Kent1999; Jan 25, 2017 at 08:06 PM.
Realistically, a tune is much easier to prove causation of engine damage. Changing timing, requested AFR, shift points in A8s, removing or raising rev limiter...those are all things with a potential for engine damage and I can see why denial of warranty is sometimes justified for a custom tune. Removing these secondary cats is a benign mod that won't/can't cause any problems. I would hope a GM engineer would have enough integrity to not try and blame an engine issue on a catless X pipe.
Originally Posted by Kent1999
Yes, indeed push back. In theory, what you've described is the way it should work. If it ended there, it would be great. However, the financial and legal realities are far from that simple.
Unfortunately, if GM resists, and decides to block a warranty claim, it takes a lot more than mentioning the magical phrase "Magnuson-Moss!" to get that decision reversed -- often next step would involve threat of legal action to compel GM to perform the warranty service.
GM has taken the stance that it doesn't have to prove direct causation -- it just has to prove that the mod created a non-certified powertrain state. See the literally dozens of threads on aftermarket tunes -- to my knowledge, not ONE of these people have prevailed against GM blocking warranty claims, despite claims that GM has to 'prove' causation. Did GM have to 'prove' the aftermarket tune caused the failure in all those cases? Did any of those plaintiffs prevail?
When you break federal emissions law with a mod, and GM's position is that the illegal mod created a non-certified and illegal powertrain state, thus it is not covered under its warranty, what will your stance be in a court of law? That your vehicle powertrain, that is now in an illegal configuration by your own unlawful acts, should still be required to be repaired under warranty? I would not want to be the one trying to convince a judge of that position.
Again, removing cats is not a legal act, such as replacing a muffler with a non-OEM unit would be (replacing OEM parts with functionally equivalent aftermarket parts *is* protected).
I talked to my local dealer about adding headers and warranty.He said to me if any codes were thrown after adding headers then I would need to pay out of pocket to remedy the
Problem.So I say If you do something that interferes throwing codes etc,be prepared to spend some money.
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