Performance intakes and exhausts are popular upgrades, but in California the rules for emissions-related parts are stricter than in most states. Check before you buy.
CARB Executive Order (EO) numbers
Aftermarket parts that can affect emissions – including many cold-air intakes, headers and some exhaust components – are only legal for street use on a California-registered vehicle if they carry a CARB Executive Order number for your specific vehicle. Parts sold “for off-road or racing use only” are not street-legal here.
- Look for the EO number on the product listing or packaging.
- Keep the paperwork (and any EO label) with the vehicle.
- You can look up an EO on the California Air Resources Board website.
Smog checks
During a smog check, the inspector looks for modifications. Parts without a valid EO can cause a visual-inspection failure.
Exhaust sound
California limits exhaust noise, and a muffler is required. Cat-back systems (everything behind the catalytic converter) are the common choice – choose one that is legal for your vehicle and within the sound limit.
Catalytic converters
Replacement converters in California must be CARB-approved for your vehicle.
Off-road recovery
Traction boards, recovery straps and shackles are for recovering a stuck vehicle – use rated gear, attach only to recovery points and keep bystanders well back.
Questions about a part? call the parts counter at (909) 623-3151.