[tom @ eas]

Originally Posted by GT3 Tim

This is exactly what it is. It is called "evaporative emissions" and all cars must meet certain criteria. Typically, California has the most stringent regulations, and cars are manufactured to meet those standards. California most definately has an evap emissions standard for new cars. CARB tests cars to ensure they meet the standards. They wil test new cars (even ones that are not released yet), and also pay people a few hundred bucks to test thier "old" cars too...to ensure they are complying with the emissions warranty as required under seperate regulation. I think the emissions warranty on cars is 7 year/100K. They can test cars anywhere within this range to make sure the manufactures are meeting the design and regulatory limits.

Most likely, because of the intake tract design, and large amount of airspace in the plenumn, gas vapors can make their way out of the intake when the car is off. Thus, they installed charcoal filter media to absorb any rogue gasoline vapors. This way, along with a number of other things, BMW can comply with the regulations.

Excellent post.