Passing smog in CA (GT4)
#1
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Hi all,
I am new to CA and am considering buying an out of state 981 GT4 that has the below exhaust mods:
Thanks in advance.
I am new to CA and am considering buying an out of state 981 GT4 that has the below exhaust mods:
- Dundon Race Headers
- Dundon GT3 exhaust conversion with cats
- Dundon Cobb tune
Thanks in advance.
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Dirtygrid (04-15-2023)
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To answer your question:
Q.) Dundon Race Headers
A.) Contact Dundon. Find out if they have what is called a State of California "E.O." Number for the headers. If they do, there will be a metal tag or stamp somewhere on the Headers themselves. You will need to know where this is for whoever performs the SMOG Check.
Q.) Dundon GT3 exhaust conversion with cats.
A.) Generally anything after the Catalytic Converters in the exhaust stream is OK. They call them "Cat-Back" exhaust systems. However, if the Catalysts are aftermarket parts, there are none that are approved. Retailers can't sell them in California and I'd be surprised if a preexisting aftermarket catalyst on a car being brought into the state would pass muster.
Q.) Dundon Cobb tune
A.) If what this is, is a software "adjustment" to the computer software the answer is no. The machine/computer that is used to pass or fail a vehicle, among other things, reads a "Check Digit" that is a part of the original computer program. FWIW this machine/computer is connected live to the California DMV and all the vehicles and all the test data that it reads are recorded and associated with that vehicle. So just a heads up. If the "Cobb tune" damaged this "Check Digit", not only will the car fail the test, reversing the software to the original program will not usually restore the "Check Digit". The only solution at this point is to purchase a new computer from the vehicle manufacturer.
Q.) Dundon Race Headers
A.) Contact Dundon. Find out if they have what is called a State of California "E.O." Number for the headers. If they do, there will be a metal tag or stamp somewhere on the Headers themselves. You will need to know where this is for whoever performs the SMOG Check.
Q.) Dundon GT3 exhaust conversion with cats.
A.) Generally anything after the Catalytic Converters in the exhaust stream is OK. They call them "Cat-Back" exhaust systems. However, if the Catalysts are aftermarket parts, there are none that are approved. Retailers can't sell them in California and I'd be surprised if a preexisting aftermarket catalyst on a car being brought into the state would pass muster.
Q.) Dundon Cobb tune
A.) If what this is, is a software "adjustment" to the computer software the answer is no. The machine/computer that is used to pass or fail a vehicle, among other things, reads a "Check Digit" that is a part of the original computer program. FWIW this machine/computer is connected live to the California DMV and all the vehicles and all the test data that it reads are recorded and associated with that vehicle. So just a heads up. If the "Cobb tune" damaged this "Check Digit", not only will the car fail the test, reversing the software to the original program will not usually restore the "Check Digit". The only solution at this point is to purchase a new computer from the vehicle manufacturer.
Last edited by Bluehighways; 04-16-2023 at 12:47 AM.
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Dirtygrid (04-16-2023)
#6
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To answer your question:
Q.) Dundon Race Headers
A.) Contact Dundon. Find out if they have what is called a State of California "E.O." Number for the headers. If they do, there will be a metal tag or stamp somewhere on the Headers themselves. You will need to know where this is for whoever performs the SMOG Check.
Q.) Dundon GT3 exhaust conversion with cats.
A.) Generally anything after the Catalytic Converters in the exhaust stream is OK. They call them "Cat-Back" exhaust systems. However, if the Catalysts are aftermarket parts, there are none that are approved. Retailers can't sell them in California and I'd be surprised if a preexisting aftermarket catalyst on a car being brought into the state would pass muster.
Q.) Dundon Cobb tune
A.) If what this is, is a software "adjustment" to the computer software the answer is no. The machine/computer that is used to pass or fail a vehicle, among other things, reads a "Check Digit" in that is a part of the original computer program. FWIW this machine/computer is connected live to the California DMV and all the vehicles and all the test data that it reads are recorded and associated with that vehicle. So just a heads up. If the "Cobb tune" damaged this "Check Digit", not only will the car fail the test, reversing the software to the original program will not usually restore the "Check Digit". The only solution at this point is to purchase a new computer from the vehicle manufacturer.
Q.) Dundon Race Headers
A.) Contact Dundon. Find out if they have what is called a State of California "E.O." Number for the headers. If they do, there will be a metal tag or stamp somewhere on the Headers themselves. You will need to know where this is for whoever performs the SMOG Check.
Q.) Dundon GT3 exhaust conversion with cats.
A.) Generally anything after the Catalytic Converters in the exhaust stream is OK. They call them "Cat-Back" exhaust systems. However, if the Catalysts are aftermarket parts, there are none that are approved. Retailers can't sell them in California and I'd be surprised if a preexisting aftermarket catalyst on a car being brought into the state would pass muster.
Q.) Dundon Cobb tune
A.) If what this is, is a software "adjustment" to the computer software the answer is no. The machine/computer that is used to pass or fail a vehicle, among other things, reads a "Check Digit" in that is a part of the original computer program. FWIW this machine/computer is connected live to the California DMV and all the vehicles and all the test data that it reads are recorded and associated with that vehicle. So just a heads up. If the "Cobb tune" damaged this "Check Digit", not only will the car fail the test, reversing the software to the original program will not usually restore the "Check Digit". The only solution at this point is to purchase a new computer from the vehicle manufacturer.
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If you frequent any of the Cars & Coffee type events, you may notice that there are a fair number of "special" cars that (for some reason) have Montana License Plates.
I'd probably want to make sure my insurance company knew where the car actually spent its life as that could be a problem at some point if you actually needed your insurance.
If you drive it frequently in any given area the CHP or local folks might notice that your "Montana" car seems to be a long term resident of California. Apparently, extended 4-season vacations for a vehicle are frowned on.
I'd probably want to make sure my insurance company knew where the car actually spent its life as that could be a problem at some point if you actually needed your insurance.
If you drive it frequently in any given area the CHP or local folks might notice that your "Montana" car seems to be a long term resident of California. Apparently, extended 4-season vacations for a vehicle are frowned on.
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#8
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If you frequent any of the Cars & Coffee type events, you may notice that there are a fair number of "special" cars that (for some reason) have Montana License Plates.
I'd probably want to make sure my insurance company knew where the car actually spent its life as that could be a problem at some point if you actually needed your insurance.
If you drive it frequently in any given area the CHP or local folks might notice that your "Montana" car seems to be a long term resident of California. Apparently, extended 4-season vacations for a vehicle are frowned on.
I'd probably want to make sure my insurance company knew where the car actually spent its life as that could be a problem at some point if you actually needed your insurance.
If you drive it frequently in any given area the CHP or local folks might notice that your "Montana" car seems to be a long term resident of California. Apparently, extended 4-season vacations for a vehicle are frowned on.
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You'd have to find someone that was willing to do a fraudulent SMOG Check. While there are ways that this can be done, it can generate real significant risk for the business doing this. The state keeps statistical data on each SMOG Station's activity. If a SMOG Station's test results fall outside the norm and/or are a bit to consistent, this will eventually invite unwanted scrutiny by the State; both for the business and the person performing the Tests.
#11
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The days of finding the "special" smog guy are about done...
Why? The fine they'd be liable for now is at minimum $10,000 and to what benefit is it to them to do this? Unless they are charging thousands to do so....The risk isn't worth the reward, and they'd lose their smog license.
Furthermore, the certificates (and test) are all electronic now, and go directly to DMV. This ain't the old days where things were hand written.
Also, Two fails and your car is flagged and then you have to go to the referee station. A royal PITA
Why? The fine they'd be liable for now is at minimum $10,000 and to what benefit is it to them to do this? Unless they are charging thousands to do so....The risk isn't worth the reward, and they'd lose their smog license.
Furthermore, the certificates (and test) are all electronic now, and go directly to DMV. This ain't the old days where things were hand written.
Also, Two fails and your car is flagged and then you have to go to the referee station. A royal PITA
Last edited by likes2drive911; 06-19-2023 at 10:23 PM.
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Kbasa (06-22-2023)
#13
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Dirty smog guys are harder to find… and more and more $ now. Plus, CA is now doing checksum scans of the ECU, so you have to completely remove the Cobb back to stock tune before you smog the car. Bring it in as is you’ll get flagged as tampered and get to visit a ref. The cats will fail a visual. Some shops are more or less detailed on the visual side.
Just not worth it… unless you register out of state these days.
Just not worth it… unless you register out of state these days.
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likes2drive911 (06-21-2023)
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What's the verdict on compliant GT4s passing a regular (no special sauce guys) smog in Cali? My car never had a tune and is running the factory exhaust manifolds so OE cats are intact. I was turned away from 3 smog shops in San Diego. The first two shops flat out said they don't do 981 or later since they can't complete the visual on the top of the motor. Third shop said to bring my car to the dealer to remove carpet and engine cover before bringing it back to complete the smog.
I can pull the carpet and top clamshell in my garage if necessary. I just want to have the correct bi-annual Cali requirement. This seems like a nightmare for GT4RS owners when the initial smog pops.
I can pull the carpet and top clamshell in my garage if necessary. I just want to have the correct bi-annual Cali requirement. This seems like a nightmare for GT4RS owners when the initial smog pops.
#15
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What's the verdict on compliant GT4s passing a regular (no special sauce guys) smog in Cali? My car never had a tune and is running the factory exhaust manifolds so OE cats are intact. I was turned away from 3 smog shops in San Diego. The first two shops flat out said they don't do 981 or later since they can't complete the visual on the top of the motor. Third shop said to bring my car to the dealer to remove carpet and engine cover before bringing it back to complete the smog.
I can pull the carpet and top clamshell in my garage if necessary. I just want to have the correct bi-annual Cali requirement. This seems like a nightmare for GT4RS owners when the initial smog pops.
I can pull the carpet and top clamshell in my garage if necessary. I just want to have the correct bi-annual Cali requirement. This seems like a nightmare for GT4RS owners when the initial smog pops.