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^^^^The stock LC 500 has two sets of catalytic Converters. The Primary and the Secondary. There are before and after measurements for the primary cats, but not the secondary cats. The primary set (one on each side) is integral to the stock manifold. When that manifold is removed, as in your case, and replaced with headers, there needs to a device put in the aft fitting to fool the ECU. That can either be mechanical or electrical. In your case, with the PPE headers, it was mechanical. See attachment.
Thanks for the reply. That’s makes sense in regards to the O2 sensor placement. Now, In regards to the catalytic converter placed after that sensor, what is the purpose? Noise reduction/modification? Helps with the exhaust smell? I know a lot of people have the second cats deleted. I was just wondering if there is any benefit to keeping the second cats?
As I said above, the Primary cats are deleted with the removal of the factory exhaust manifolds. The cats in the mid pipes of the PPE exhaust system are the only catalytic converters in your exhaust system.
Note: The cats are an optional add-on to the PPE exhaust system. See Optional Price schedule from PPE's web site:
Lou
Last edited by flowrider; Nov 7, 2019 at 10:20 AM.
The reason I ask is because my new midpipe from Novel has 200 cell catalytic converters. My current PPE midpipe does not. Other than environmental benefits I was unsure if there were any other reasons to keep the secondary cats.
^^^^For me the purpose was being a good citizen. The catalytic converter reduces pollutants that damage the atmosphere. Wikipedia describes it as:
As I said above, the Primary cats are deleted with the removal of the factory exhaust manifolds. The cats in the mid pipes of the PPE exhaust system are the only catalytic converters in your exhaust system.
Note: The cats are an optional add-on to the PPE exhaust system. See Optional Price schedule from PPE's web site:
Lou
I would love to hear your new exhaust with the resonators. My current set up from PPE is without resonators and without cats, and I have wondered how much different it would sound with resonators.
^^^^Some folks notice a gas smell without cats, some do not. I wasn't aware your PPE system was sans options And no, environmental reasons is the reason cars have cats installed. And if Kentucky ever requires a smog check, your car won't pass without cats.
The reason I ask is because my new midpipe from Novel has 200 cell catalytic converters. My current PPE midpipe does not. Other than environmental benefits I was unsure if there were any other reasons to keep the secondary cats.
Congrats on that Novel midpipe. I know they don't come cheap! I'm curious to know the result - would love to hear a sound clip once installed plz!
Congrats on that Novel midpipe. I know they don't come cheap! I'm curious to know the result - would love to hear a sound clip once installed plz!
I will have it installed in the next week or so. I just installed the Quantum Solenoid and I plan to get the car back on the dyno next Friday to see what the solenoid did for my car. After that I’ll swap out the midpipe, and then get it back on the dyno to see if there is any difference in power. Theoretically an X pipe should make more power compared to an H pipe, like on the PPE midpipe. But the catalytic converter on the novel system will likely reduce flow and therefore reduce power some. We shall see! Regardless, it will sound different.
And no, environmental reasons is the reason cars have cats installed. And if Kentucky ever requires a smog check, your car won't pass without cats.
