How To Buy A Catalytic Converter

What is a Catalytic Converter?

A Catalytic Converter is an emissions control device that converts harmful pollutants into less harmful emissions before leaving a vehicle’s exhaust. Buying the right catalytic converter is essential for your vehicle to be legally registered and driven on public roads.
When buying a catalytic converter, there are several things to consider:

    Converter Grade

    For 49-state (non-California) vehicles manufactured since 1996 (OBD II), there are two choices: HM (Heavy Metal) or OEM-grade. 

      • HM Converters are intended for 49-state vehicles with a federal or EPA certification.
      • OEM-grade Converters are intended for CARB-certified (California Air Resources Board) registered outside of California.

      For California OBD II vehicles, there is only one choice: a CARB-approved catalytic converter.

      For 1995 and older (pre-OBD II) vehicles registered outside of California (49-state):
        • Check the emissions tag in the engine compartment, which should be located on the underside of the hood, on the radiator core support or on one of the strut towers.
        • The emissions tag specifies the type of converter on your vehicle: two-way, three-way plus air or three-way.
        • Engine size and gross vehicle weight are also found on the emissions tag.
        • Use the emissions tag information to guide you through the Shop by Vehicle tool on

      For pre-OBD II vehicles registered in California:
        • Year, make and model of the vehicle are used to select the appropriate catalytic converter.
        • The Shop by Vehicle tool on will help you make the right selection.


      Selecting the right converter

      Step 1

      Locate your "Vehicle Emissions Control Information" (VECI) tag on or near one of three locations:
        1. The underside of the hood
        2. Suspension Tower
        3. Radiator Shroud


        Step 2

        Depending on if your vehicle is registered inside or outside the state of CA, NY or ME will determine which of the following information you will need. You should choose from the two options below.
        • Option 1: For OBDII vehicles registered and operated INSIDE of the state of CA, NY, ME or CO:
          • Locate the EFN (Engine Family Displacement) Code
        • Option 2: For OBDII vehicles registered and operated OUTSIDE the state of CA, NY, ME or CO:
          • Determine the Emissions Level



          Step 3

          Using all information gathered, you can shop all available Catalytic Converters online for your Car, Truck, or SUV by entering your vehicle details on our Shop by Vehicle tool.

          All MagnaFlow catalytic converters are backed by a limited 5-year/50,000 mile construction warranty and a limited 25,000-mile emissions warranty.


          Have questions? Give us a call at 1-800-990-0905. You can also refer to MagnaFlow’s 49-state and California MagnaFlow catalogs.