When modifying a vehicle, emissions compliance is a crucial factor, especially for our customers around the Salt Lake City area. Whether you’re boosting performance or upgrading for reliability, ignoring emissions regulations can lead to hefty fines, failed inspections, and major headaches. Here are key emissions-related aspects to consider:
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Catalytic Converter: Most aftermarket downpipes replace the stock catalytic converter. For our local customers, the catalytic converter is one of the most important emissions-related components. If your car originally has two catalytic converters and you replace them with just one, you may fail emissions testing, depending on your county's regulations. Additionally, aftermarket converters that lack CARB certification may result in failed visual or performance tests. We always recommend OE catalytic converters for the highest chance of passing emissions tests. A downpipe that uses a GESI catalytic converter with a CARB number is the next best option. Cobb Tuning offers the widest range of CARB-compliant downpipes on the market!
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Oxygen Sensors: Altering exhaust or intake systems can affect oxygen sensor readings, which regulate the air-fuel mixture. An improper balance can lead to increased emissions and poor performance. Always ensure sensors are properly positioned and functioning. We recommend using OE oxygen sensors for the most reliable results. Some may try using a defouler to trick the vehicle into avoiding a check engine light due to a poorly performing catalytic converter. However, in our region, this will result in an automatic visual fail during inspection.
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Exhaust Gas Recirculation (EGR): Some performance upgrades may interfere with the EGR system, which helps reduce nitrogen oxide (NOx) emissions. Make sure modifications don’t disable or hinder this system.
We always recommend OE units for EGR systems. -
Tuning and ECU Modifications: While tuning can unlock power, it may also affect emissions controls. Ensure that any ECU remapping is done by a reputable source and remains compliant with emissions standards. For those using a tuner solely to monitor vehicle parameters, be aware that it may still result in a visual fail during inspection. We recommend removing any cables, mounts, or tuning devices from the vehicle prior to testing.
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Venting to Atmosphere: Some common vehicle modifications may put you at risk of failing an emissions test. A simple rule of thumb: any air that enters the system should pass through a catalytic converter when it exits. Be cautious of VTA (vent-to-atmosphere) blow-off valves, catch cans with VTA, or divorced downpipes with an open dump for the wastegate, as these may lead to a failed test.
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Aftermarket Parts with CARB Certification: If you live in a state with strict emissions laws, look for parts with California Air Resources Board (CARB) certification. These parts are tested and approved to meet emissions standards.
We hope the insights we've shared from our extensive experience modifying cars while considering emissions compliance are helpful in guiding your decisions. We always recommend researching your local laws and regulations, as they can vary depending on your location. If you need advice on which parts will best suit your goals while keeping your vehicle emissions-friendly, please don't hesitate to reach out to us!