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200-400% hasn't been my experience, but I'll give you maybe they should expand carb nationwide to increase the demand side of the curve, lowering costs overall.

200-400% hasn't been my experience, but I'll give you maybe they should expand carb nationwide to increase the demand side of the curve, lowering costs overall. >if the cat isn't working, the vehicle should fail its regular smog test. The vehicle ECU monitors the exhaust composition before and after the first catalyst. Downstream, the performance is not monitored by the computer. afiak the ECU doesn't have the capability to monitor nox and hydrocarons directly. The reason for this is that a cheap, reliable oxygen sensor is employed for monitoring. Maybe it's possible to add that regulation federally.

pengaru 5y ago
> 200-400% hasn't been my experience, but I'll give you maybe they should expand carb nationwide to increase the demand side of the curve, lowering costs overall. 49-state legal, direct-fit: $118 https://www.ebay.com/itm/253120020746 https://www.ebay.com/itm/253120020746 CA-legal, universal: $776 https://www.ebay.com/itm/304044103436 https://www.ebay.com/itm/304044103436 CA-legal direct-fit: $1048 (!) https://www.ebay.com/itm/174087409201 https://www.ebay.com/itm/174087409201 > The vehicle ECU monitors the exhaust composition before and after the first catalyst. Downstream, the performance is not monitored by the computer. afiak the ECU doesn't have the capability to monitor nox and hydrocarons directly. The reason for this is that a cheap, reliable oxygen sensor is employed for monitoring. I don't see what any of this has to do with smog tests, and it's not even accurate for all vehicles (pre obd2 has just a single narrow band o2 sensor before the cat) but this is completely off-topic. The tests shouldn't rely on the vehicle's systems for measuring emissions, it just creates more opportunities for fuckery. CA smog tests use their own emissions monitoring equipment and have already employed rolling roads to put the vehicles through varying loads during the test.
- cartoonworld 5y ago
  I gotcha, it's. 1994-97 miata and there aren't a lot of cats left. Such is the life of a classic car owner. >I don't see what any of this has to do with smog tests, and it's not even accurate for all vehicles (pre obd2 has just a single narrow band o2 sensor You mentioned the smog tests, saying if the vehicle can't measure them they aren't worth a damn >If the smog checks are worth a damn it shouldn't be necessary to certify the catalysts; if the cat isn't working, the vehicle should fail its regular smog test. Thats why it is not off-topic. No cars monitor for the smog gasses. That's why Cali uses a special sniffer and a dyno to run a load test. In order to accomplish their stated goal of reducing pbotochemical smog, they must employ a dyno to test under load to monitor the production of nox and hydrocarbons out the tail pipe. The oxygen sensors pre-obd2 were never used in any state for emissions, In my state we did a 2 speed idle test on a dyno which is being retired currently as all required vehicles are now exempt from this test. We still are running oxygen sensors for engine management in every car. They do not sense any smog gasses.
- rasz 5y ago
  the "49-state legal" one is empty inside, its a legal scam. Works because those 49 states dont actually test for CO, HC or NOx. They merely use ODB computer checking for - check engine light - fault codes - readiness monitors its a legislative joke. In EU even a 20 year old bmw e36 cat still goes for ~$1K, because we actually test emissions.
  - pengaru 5y ago
    Lies. I bought that ebay cat last year after my cat was destroyed in a U-joint failure when the prop shaft impacted it at speed. It is not empty, and the car passes a CA sniffer test with flying colors using it. It is pretty cheaply constructed though, thin walls, and the ID seemed a bit smaller than stock so not great for power.
    - cartoonworld 5y ago
      Sorry about your u-joint headaches. The cheap ones are less resilient as you noticed. When hydrocarbons (such as from blowby or imperfectly metered fuel) hit the substrate it works against the catalyst chemistry and the catalyst produces combustion clearing it up. But this skyrockets the temperatures, damages or melts the substrate reducing its effectiveness using up the substrate. There is a lot of expansion and contraction in a 1000-degree cat, failing ones can double that, so the poor bonding techniques will turn it into a rattle can fast. Thin walls, less substrate, and poor bonding lead them to fail prematurely. Good luck.

pengaru 5y ago

> 200-400% hasn't been my experience, but I'll give you maybe they should expand carb nationwide to increase the demand side of the curve, lowering costs overall. 49-state legal, direct-fit: $118 https://www.ebay.com/itm/253120020746 https://www.ebay.com/itm/253120020746 CA-legal, universal: $776 https://www.ebay.com/itm/304044103436 https://www.ebay.com/itm/304044103436 CA-legal direct-fit: $1048 (!) https://www.ebay.com/itm/174087409201 https://www.ebay.com/itm/174087409201 > The vehicle ECU monitors the exhaust composition before and after the first catalyst. Downstream, the performance is not monitored by the computer. afiak the ECU doesn't have the capability to monitor nox and hydrocarons directly. The reason for this is that a cheap, reliable oxygen sensor is employed for monitoring. I don't see what any of this has to do with smog tests, and it's not even accurate for all vehicles (pre obd2 has just a single narrow band o2 sensor before the cat) but this is completely off-topic. The tests shouldn't rely on the vehicle's systems for measuring emissions, it just creates more opportunities for fuckery. CA smog tests use their own emissions monitoring equipment and have already employed rolling roads to put the vehicles through varying loads during the test.

cartoonworld 5y ago
I gotcha, it's. 1994-97 miata and there aren't a lot of cats left. Such is the life of a classic car owner. >I don't see what any of this has to do with smog tests, and it's not even accurate for all vehicles (pre obd2 has just a single narrow band o2 sensor You mentioned the smog tests, saying if the vehicle can't measure them they aren't worth a damn >If the smog checks are worth a damn it shouldn't be necessary to certify the catalysts; if the cat isn't working, the vehicle should fail its regular smog test. Thats why it is not off-topic. No cars monitor for the smog gasses. That's why Cali uses a special sniffer and a dyno to run a load test. In order to accomplish their stated goal of reducing pbotochemical smog, they must employ a dyno to test under load to monitor the production of nox and hydrocarbons out the tail pipe. The oxygen sensors pre-obd2 were never used in any state for emissions, In my state we did a 2 speed idle test on a dyno which is being retired currently as all required vehicles are now exempt from this test. We still are running oxygen sensors for engine management in every car. They do not sense any smog gasses.
rasz 5y ago
the "49-state legal" one is empty inside, its a legal scam. Works because those 49 states dont actually test for CO, HC or NOx. They merely use ODB computer checking for - check engine light - fault codes - readiness monitors its a legislative joke. In EU even a 20 year old bmw e36 cat still goes for ~$1K, because we actually test emissions.
- pengaru 5y ago
  Lies. I bought that ebay cat last year after my cat was destroyed in a U-joint failure when the prop shaft impacted it at speed. It is not empty, and the car passes a CA sniffer test with flying colors using it. It is pretty cheaply constructed though, thin walls, and the ID seemed a bit smaller than stock so not great for power.
  - cartoonworld 5y ago
    Sorry about your u-joint headaches. The cheap ones are less resilient as you noticed. When hydrocarbons (such as from blowby or imperfectly metered fuel) hit the substrate it works against the catalyst chemistry and the catalyst produces combustion clearing it up. But this skyrockets the temperatures, damages or melts the substrate reducing its effectiveness using up the substrate. There is a lot of expansion and contraction in a 1000-degree cat, failing ones can double that, so the poor bonding techniques will turn it into a rattle can fast. Thin walls, less substrate, and poor bonding lead them to fail prematurely. Good luck.