1. Consult your owner's manual: This will likely have the information you are looking for.
2. Look up your engine code: You can find this on your engine block or on your vehicle's registration papers. Once you have the engine code, you can search online for information about that specific engine, including the cam type.
3. Contact a BMW dealer or mechanic: They will be able to provide you with the correct information.
Please note that cam types can vary depending on the specific engine in your 2005 BMW X3.