Check your cats...

[calbert1999]

Originally Posted by 69 Rebel

Let's all agree to disagree on why cats fail. The fact still remains they are failing. We need a solution, the people making the cats should do some R&D and find out exactly why they are failing and come up with a cat for high HP cars period. We obviously need them for emmissions, noise ,smell etc. and there is obviously a market for it.

Is it just us or is this really rocket science?

Make better CAT's, gut'ing or no CAT's is illegal........ is anyone (Kooks, DynaTech, Magnaflow, Corsa, Borla, et al) listening?

Funny how none of the manufacturers have anything to say on the topic.

[Blue70SS]

Will it be "Cat Protection Off"





"Broken Tuning Fork"




"Angel Cat on Cloud 9"




or my favorite..... "Cat Sleeping on my Shelf"




Cast your votes!!!!!!!!!!! I'm done

[Blue70SS]

Originally Posted by calbert1999

Is it just us or is this really rocket science?

Make better CAT's, gut'ing or no CAT's is illegal........ is anyone (Kooks, DynaTech, Magnaflow, Corsa, Borla, et al) listening?

Funny how none of the manufacturers have anything to say on the topic.

Okay..... now I'm done

[mikepage0007]

Originally Posted by calbert1999

Is it just us or is this really rocket science?

Make better CAT's, gut'ing or no CAT's is illegal........ is anyone (Kooks, DynaTech, Magnaflow, Corsa, Borla, et al) listening?

Funny how none of the manufacturers have anything to say on the topic.

i gotta agree...performance minded header companies , should be making performance cats...if there considered hi flow, .are these the same exhaust performance companies selling hi flow cats for the 638hp vette...or do none of these aftermarket companies sell headers and cats for the vettes...if they know we and the vettes are running 600+hp then they need to design cats that work with this hp.....period...or sell them with a "do not use above 500hp"..i never heard any vendor stating "do not use above 500hp"..its, obvious that there is a cat issue as time is starting to show there problems...have also seen this in other sites, so do not believe that camaro5 is isolated to this issue...imo..

[calbert1999]

Originally Posted by mikepage0007

i gotta agree...performance minded header companies , should be making performance cats...if there considered hi flow, .are these the same exhaust performance companies selling hi flow cats for the 638hp vette...or do none of these aftermarket companies sell headers and cats for the vettes...if they know we and the vettes are running 600+hp then they need to design cats that work with this hp.....period...or sell them with a "do not use above 500hp"..i never heard any vendor stating "do not use above 500hp"..its, obvious that there is a cat issue as time is starting to show there problems...have also seen this in other sites, so do not believe that camaro5 is isolated to this issue...imo..

[MarylandSpeed]

Originally Posted by calbert1999

Is it just us or is this really rocket science?

Make better CAT's, gut'ing or no CAT's is illegal........ is anyone (Kooks, DynaTech, Magnaflow, Corsa, Borla, et al) listening?

Funny how none of the manufacturers have anything to say on the topic.

It's all a matter of price. You can have anything you want if you are willing to pay for it. Kooks for instance has a new cat that will not throw codes...but it has not been rolled out yet because they cost almost $300 more than a normal cat. Are you willing to pay $700 for cats on top of what headers cost?

[4thGen427CI]

Originally Posted by MarylandSpeed

It's all a matter of price. You can have anything you want if you are willing to pay for it. Kooks for instance has a new cat that will not throw codes...but it has not been rolled out yet because they cost almost $300 more than a normal cat. Are you willing to pay $700 for cats on top of what headers cost?

Sounds like there is people that will pay cause they want to play without the codes. I will pay $700 for cats if they never melt. But we all know that won't happen without proper tuning. I'm just curious no one answered my question last time. Can a set of turbo's replace the cats?

[bluetorp]

Originally Posted by Caliman93230

Bluetrop I don't think people want to take the risk or be that one in 100 that had a cat failure and blew the engine, are you a manufacture of high flow cats? do you sell them.

Find me someone who's melted cat blew their engine. Where is this assumption that melted cats are blowing engines coming from?

EDIT: To clarify, I'm not saying a melted cat will never blow an engine. But as MarylandSpeed stated, one would have to ignore some pretty severe driveability issues for a significant time for a melted cat to result in an engine failure.

[bluetorp]

Originally Posted by Blue70SS

Higher potential for cat failure at higher boosted HP levels and harder to tune for should be the message. It's good to know that the tune can be the cause and tuners could be turning off cat protection, etc, etc. Those wanting to run cats under these conditions will now be better educated and hopefully wiser.

That's a fairly good summation. Potential for cat failure exists at all power levels, and is directly proportional to the amount of power you have, and how much you use that power. Less than optimal tuning then becomes much more likely to result in damage to the cat.

Originally Posted by Blue70SS

On another note (to all)... I called a cat manufacturer (to remain nameless for sake of argument not needed), and they thought cat failures on higher boosted engines was primarily happening not during boost, but on deceleration, but can be properly tuned. I asked what properly tuned was, in particular if they were finding too rich or too lean affected it more so. Response was, "it can be tuned for". A more helpfull "note to tuners: parameters that work best on our cats" sheet would be more helpful. "Tune" just seems to be the blanket statement still.

"Tune" has become a blanket statement because it is so vital for protecting the cat. Lets take a technical look at what we're talking about:

DISCLAIMER: This will be moderately technical, but everyone should be able to follow it. There will be a bunch of words. Deal with it, or TL;DR, as is your prerogative.

(Note for those with an understanding of thermodynamics: I'm appropriating terms and vastly simplifying. Don't crucify me. )

A catalytic converter, like any other substance, has a thermal mass (ability to resist changes in temperature, if you will) and a heat capacity (in this case, we'll consider the heat capacity to be the temperature threshold at which the cat material melts). Once there is enough thermal energy induced in the cat to override the ability of its thermal mass to keep its temperature within its heat capacity, the cat melts. Simple as that.

So, what induces this heat in the cat? Exhaust gasses.

Exhaust gas has a thermal force, which is simply it's ability to transfer its thermal energy (into the cat in this case). The thermal force of the exhaust gas is mainly a factor of HEAT and VOLUME. The greater the heat, the greater the thermal force. The greater the volume, the greater the thermal force. The goal is managing the thermal force of the exhaust gas so that it does not overcome the combined effects of the thermal mass and heat capacity of the cat.

When you increase power in an engine, you increase it's efficiency as an air pump, which means mainly that you're allowing it to flow more air. Adding compression to the intake charge with a supercharger/turbo, adding displacement, changing the cam, etc. all increase the amount of air moving through the engine. This increases the volume component of the thermal force of our exhaust gas. This we simply have to live with. But what about the other component of our thermal force, heat?

Broadly speaking, the leaner the AFR, the higher the heat of the exhaust gasses. This we can control. The first way we do this is by tuning an appropriate PE (performance enrichment - WOT essentially) AFR. But what about normal, closed-loop operation, where the PCM commands the stoichiometric AFR of 14.7:1 (or more correctly, what it thinks is stoich based on the narrowband O2 readings)? Here is where a tuner can get a bit exotic, or where we can let the COT protection settings run the show.

As a tuner, I can disable closed-loop operation altogether. This disables PCM control of the AFR based on O2 feedback, and means I can set the fueling to be whatever I want without the PCM mucking things up. Dedicated open-loop operation does require monitoring and periodic adjustment, though. I could also change the stoichiometric setting in the PCM. However, since the narrowband O2's are not accurate except at stoich, this would require me to use wideband O2's with a controller that allows me to sim a narrowband output, such as an LC-1.

Since GM is limited to running stoich due to emissions regulations, they use COT protection. All this does is richen the AFR when it determines that a certain temperature threshold has been reached. I do not know specifically how it does this- as far as I know no one has hacked into the code sufficiently to determine what the algorithm is and what inputs it is using (will have to research a bit), but looking at the stock settings it seems like the PCM is performing a calculation to estimate either EGT or temp in the cat itself. The variables we can see in COT protection are a master enable/disable, a "Max Enrichment" fuel/air multiplier of the current commanded AFR, and three separate temperature thresholds. Again, I don't think the information is available yet as to how it applies the max enrichment vs. the different temperature thresholds or what the enrichment hysteresis is, but we can easily see that as a tuner, I have the ability to disable COT protection, or make it more or less aggressive.

As we increase the ability of our engines to impart more and more thermal force into the exhaust gasses via increased volume, we have to be more and more diligent about managing the heat of the exhaust gasses if we don't want to destroy catalytic converters.

Originally Posted by mikepage0007

if they know we and the vettes are running 600+hp then they need to design cats that work with this hp.....period...or sell them with a "do not use above 500hp"..i never heard any vendor stating "do not use above 500hp"..

They did design cats that work with this HP. At around 600 RWHP under anything but the most rigorous race usage, we're just not exceeding the capabilities of the current generation of high flow cats. If that was the case, everyone's cats would be failing at these power levels, not an isolated few. These isolated few can probably all be traceable to manufacturing defects, improper tuning, and extreme usage.

Can manufacturers design and produce a more resilient catalytic converter? Of course. Increasing thermal mass by increasing size, increasing heat dissipation via material selection and heat sinking, increasing heat capacity by changing catalytic material/metallurgy may all be viable solutions. They also increase form factor and cost to the manufacturer AND consumer, both of which serve to limit the potential market available to the manufacturer and thus increase the risk to the manufacturer of designing and bringing such a product to market.

[mikepage0007]

Originally Posted by bluetorp

That's a fairly good summation. Potential for cat failure exists at all power levels, and is directly proportional to the amount of power you have, and how much you use that power. Less than optimal tuning then becomes much more likely to result in damage to the cat.



"Tune" has become a blanket statement because it is so vital for protecting the cat. Lets take a technical look at what we're talking about:

DISCLAIMER: This will be moderately technical, but everyone should be able to follow it. There will be a bunch of words. Deal with it, or TL;DR, as is your prerogative.

(Note for those with an understanding of thermodynamics: I'm appropriating terms and vastly simplifying. Don't crucify me. )

A catalytic converter, like any other substance, has a thermal mass (ability to resist changes in temperature, if you will) and a heat capacity (in this case, we'll consider the heat capacity to be the temperature threshold at which the cat material melts). Once there is enough thermal energy induced in the cat to override the ability of its thermal mass to keep its temperature within its heat capacity, the cat melts. Simple as that.

So, what induces this heat in the cat? Exhaust gasses.

Exhaust gas has a thermal force, which is simply it's ability to transfer its thermal energy (into the cat in this case). The thermal force of the exhaust gas is mainly a factor of HEAT and VOLUME. The greater the heat, the greater the thermal force. The greater the volume, the greater the thermal force. The goal is managing the thermal force of the exhaust gas so that it does not overcome the combined effects of the thermal mass and heat capacity of the cat.

When you increase power in an engine, you increase it's efficiency as an air pump, which means mainly that you're allowing it to flow more air. Adding compression to the intake charge with a supercharger/turbo, adding displacement, changing the cam, etc. all increase the amount of air moving through the engine. This increases the volume component of the thermal force of our exhaust gas. This we simply have to live with. But what about the other component of our thermal force, heat?

Broadly speaking, the leaner the AFR, the higher the heat of the exhaust gasses. This we can control. The first way we do this is by tuning an appropriate PE (performance enrichment - WOT essentially) AFR. But what about normal, closed-loop operation, where the PCM commands the stoichiometric AFR of 14.7:1 (or more correctly, what it thinks is stoich based on the narrowband O2 readings)? Here is where a tuner can get a bit exotic, or where we can let the COT protection settings run the show.

As a tuner, I can disable closed-loop operation altogether. This disables PCM control of the AFR based on O2 feedback, and means I can set the fueling to be whatever I want without the PCM mucking things up. Dedicated open-loop operation does require monitoring and periodic adjustment, though. I could also change the stoichiometric setting in the PCM. However, since the narrowband O2's are not accurate except at stoich, this would require me to use wideband O2's with a controller that allows me to sim a narrowband output, such as an LC-1.

Since GM is limited to running stoich due to emissions regulations, they use COT protection. All this does is richen the AFR when it determines that a certain temperature threshold has been reached. I do not know specifically how it does this- as far as I know no one has hacked into the code sufficiently to determine what the algorithm is and what inputs it is using (will have to research a bit), but looking at the stock settings it seems like the PCM is performing a calculation to estimate either EGT or temp in the cat itself. The variables we can see in COT protection are a master enable/disable, a "Max Enrichment" fuel/air multiplier of the current commanded AFR, and three separate temperature thresholds. Again, I don't think the information is available yet as to how it applies the max enrichment vs. the different temperature thresholds or what the enrichment hysteresis is, but we can easily see that as a tuner, I have the ability to disable COT protection, or make it more or less aggressive.

As we increase the ability of our engines to impart more and more thermal force into the exhaust gasses via increased volume, we have to be more and more diligent about managing the heat of the exhaust gasses if we don't want to destroy catalytic converters.



They did design cats that work with this HP. At around 600 RWHP under anything but the most rigorous race usage, we're just not exceeding the capabilities of the current generation of high flow cats. If that was the case, everyone's cats would be failing at these power levels, not an isolated few. These isolated few can probably all be traceable to manufacturing defects, improper tuning, and extreme usage.

Can manufacturers design and produce a more resilient catalytic converter? Of course. Increasing thermal mass by increasing size, increasing heat dissipation via material selection and heat sinking, increasing heat capacity by changing catalytic material/metallurgy may all be viable solutions. They also increase form factor and cost to the manufacturer AND consumer, both of which serve to limit the potential market available to the manufacturer and thus increase the risk to the manufacturer of designing and bringing such a product to market.

good write up.it seems that the real issues come from fi engines, this is where header companies should step up and make you aware { disclaimer} that due to much higher heat -cat breakdown could occur..i am in procees of dropping in a 427lsx with whipple , and there is no way that i am gonna put cats on...i would like to, but if its gonna fail ...why bother..for every 10k miles of dd , it might see a half doizen track passes...but at 15psi, i don,t believe the cats will hold up..

[bluetorp]

Originally Posted by mikepage0007

good write up.it seems that the real issues come from fi engines, this is where header companies should step up and make you aware { disclaimer} that due to much higher heat -cat breakdown could occur..i am in procees of dropping in a 427lsx with whipple , and there is no way that i am gonna put cats on...i would like to, but if its gonna fail ...why bother..for every 10k miles of dd , it might see a half doizen track passes...but at 15psi, i don,t believe the cats will hold up..

I've seen cats survive behind similar setups. I wouldn't assume that if you put cats on that they would be doomed to fail. But, lacking a specific reason to need/want cats installed, there really isn't a downside to not putting them on in the first place.

[JANNETTYRACING]

Originally Posted by bluetorp

That's a fairly good summation. Potential for cat failure exists at all power levels, and is directly proportional to the amount of power you have, and how much you use that power. Less than optimal tuning then becomes much more likely to result in damage to the cat.



"Tune" has become a blanket statement because it is so vital for protecting the cat. Lets take a technical look at what we're talking about:

DISCLAIMER: This will be moderately technical, but everyone should be able to follow it. There will be a bunch of words. Deal with it, or TL;DR, as is your prerogative.

(Note for those with an understanding of thermodynamics: I'm appropriating terms and vastly simplifying. Don't crucify me. )

A catalytic converter, like any other substance, has a thermal mass (ability to resist changes in temperature, if you will) and a heat capacity (in this case, we'll consider the heat capacity to be the temperature threshold at which the cat material melts). Once there is enough thermal energy induced in the cat to override the ability of its thermal mass to keep its temperature within its heat capacity, the cat melts. Simple as that.

So, what induces this heat in the cat? Exhaust gasses.

Exhaust gas has a thermal force, which is simply it's ability to transfer its thermal energy (into the cat in this case). The thermal force of the exhaust gas is mainly a factor of HEAT and VOLUME. The greater the heat, the greater the thermal force. The greater the volume, the greater the thermal force. The goal is managing the thermal force of the exhaust gas so that it does not overcome the combined effects of the thermal mass and heat capacity of the cat.

When you increase power in an engine, you increase it's efficiency as an air pump, which means mainly that you're allowing it to flow more air. Adding compression to the intake charge with a supercharger/turbo, adding displacement, changing the cam, etc. all increase the amount of air moving through the engine. This increases the volume component of the thermal force of our exhaust gas. This we simply have to live with. But what about the other component of our thermal force, heat?

Broadly speaking, the leaner the AFR, the higher the heat of the exhaust gasses. This we can control. The first way we do this is by tuning an appropriate PE (performance enrichment - WOT essentially) AFR. But what about normal, closed-loop operation, where the PCM commands the stoichiometric AFR of 14.7:1 (or more correctly, what it thinks is stoich based on the narrowband O2 readings)? Here is where a tuner can get a bit exotic, or where we can let the COT protection settings run the show.

As a tuner, I can disable closed-loop operation altogether. This disables PCM control of the AFR based on O2 feedback, and means I can set the fueling to be whatever I want without the PCM mucking things up. Dedicated open-loop operation does require monitoring and periodic adjustment, though. I could also change the stoichiometric setting in the PCM. However, since the narrowband O2's are not accurate except at stoich, this would require me to use wideband O2's with a controller that allows me to sim a narrowband output, such as an LC-1.

Since GM is limited to running stoich due to emissions regulations, they use COT protection. All this does is richen the AFR when it determines that a certain temperature threshold has been reached. I do not know specifically how it does this- as far as I know no one has hacked into the code sufficiently to determine what the algorithm is and what inputs it is using (will have to research a bit), but looking at the stock settings it seems like the PCM is performing a calculation to estimate either EGT or temp in the cat itself. The variables we can see in COT protection are a master enable/disable, a "Max Enrichment" fuel/air multiplier of the current commanded AFR, and three separate temperature thresholds. Again, I don't think the information is available yet as to how it applies the max enrichment vs. the different temperature thresholds or what the enrichment hysteresis is, but we can easily see that as a tuner, I have the ability to disable COT protection, or make it more or less aggressive.

As we increase the ability of our engines to impart more and more thermal force into the exhaust gasses via increased volume, we have to be more and more diligent about managing the heat of the exhaust gasses if we don't want to destroy catalytic converters.



They did design cats that work with this HP. At around 600 RWHP under anything but the most rigorous race usage, we're just not exceeding the capabilities of the current generation of high flow cats. If that was the case, everyone's cats would be failing at these power levels, not an isolated few. These isolated few can probably all be traceable to manufacturing defects, improper tuning, and extreme usage.

Can manufacturers design and produce a more resilient catalytic converter? Of course. Increasing thermal mass by increasing size, increasing heat dissipation via material selection and heat sinking, increasing heat capacity by changing catalytic material/metallurgy may all be viable solutions. They also increase form factor and cost to the manufacturer AND consumer, both of which serve to limit the potential market available to the manufacturer and thus increase the risk to the manufacturer of designing and bringing such a product to market.

Well Written and right on Target.

[Blue70SS]

Originally Posted by MarylandSpeed

It's all a matter of price. You can have anything you want if you are willing to pay for it. Kooks for instance has a new cat that will not throw codes...but it has not been rolled out yet because they cost almost $300 more than a normal cat. Are you willing to pay $700 for cats on top of what headers cost?

If they're proven to survive and no quibble guarantee longer than 2 years, HECK YES!
....and Ditto what Calbert1999 said below!

..... and very good writeup Bluetorp!

Specific settings or ranges affecting COT would be helpful from the Cat manufacturer - not that the average person should make the changes themselves, but provide it to the tuner and take an active role in ensuring things are safe. I for one, like to see and compare why the tune is changed and understand the process. Definitely makes me appreciate what a good tuner does.

[calbert1999]

Originally Posted by MarylandSpeed

It's all a matter of price. You can have anything you want if you are willing to pay for it. Kooks for instance has a new cat that will not throw codes...but it has not been rolled out yet because they cost almost $300 more than a normal cat. Are you willing to pay $700 for cats on top of what headers cost?

I could be over-thinking this; By trade I'm trained to be risk adverse. So, I'd think in the grand scheme of things $300 to manage the risk is a drop in the bucket to avert:

1. Need for a new engine
2. Loss of use
3. Rental of vehicle
4. Loss of other investments in parts (for example gut'ting CAT's is a waste of money to begin with)
5. Legalities (tickets)
6. Challenges passing ride clean tests (re-install / un-install CAT's every 2yrs.) = additional labour costs.
7. Time loss, et al.

Just seems like a very logical choice to me.