Originally Posted by Coyote Red
I lied when I said my thoughts and comments were over.
Now if I am reading what you posted correctly there will be a tipping point where the pollutant level of the VW will be equal or less than that of a Taurus. That point will only come when the fuel savings of a VW will be 5.5x greater than the Taurus.
From my SWAG numbers of MPG earlier and some calculations just now at no point will the VW pollute less since the difference in MPG is less than of 5.5X what the Taurus gets for MPG. I used 5.5 since that was what the highest difference between the two emission standards you posted. The only way for the VW to achieve that tipping point would be if the MPG was at least 110MPG. Correct in my thinking or no.
Well, sort of - and I'm not the guy to give you a 100% "yes or no" answer. Car's "emissions performance" is rated with a series of standardized tests that have been developed starting back in the early seventies. They have been updated and revised, but still don't reflect everyone's usage - so depending on the driver, these cars could perform quite differently than the emission standards they certify to.
Clear as mud?
I also have no idea what secondary pollutants are created while refining these fuels - so I can't speak to that.