Is there any info available on how much VW TDI pollutes compared to less efficient gas SUVs?

msfranw

Trying to comprehend how much I'll be polluting if I keep my Jetta TDI wagon without fixing vs selling back and buying less fuel efficient gas Subaru Forrester or Outback.

kyfdx

It's a simple math problem, if you can agree on some assumptions.

Assumptions
1) Gas and diesel engines that meet EPA requirements emit the same amount of pollutants per gallon of fuel used.
2) The "bad" TDIs emit 10 times the pollutants allowed by regulation
3) The TDI achieves 50% better fuel mileage than a Forester.

To keep it simple, let's assume 90 miles of use, and MPGs of 45 and 30 for the TDI and Forester

The Forester will use 3 gallons of fuel, at a base emission level of 1, for a score of 3 emission points
The TDI will use 2 gallons of fuel, at a base emission level of 10, for a score of 20 emission points.

The result: The TDI will emit 6.67 times the amount of pollutants as the Forester, for the same distance driven.

Tweak those assumptions however you wish. Unless you can assume that the TDI is just a little worse than regulations allow, it's going to be polluting a lot more.

Then again, if you listen to the news it's all about lawn mowers and cows, anyway..

msfranw

Thanks for your response. Makes sense. However, what still is an unknown (to me anyway) is assumption #2. It is true that the Nox is at some multiple greater than that allowed. But it isn't the only component of the emissions, which begs the question whether, in total, the pollutants place the Jetta at 10x or more per gallon excess emissions or a smaller percent effect as a portion of the whole emission. I have yet to see any discussion on this factor from VW, regulators and/or industry analysts.

kyfdx

Yeah... I only know the math part. That's why I called them assumptions.
It still puts out less methane than a cow, I bet.

I bet you really like that vehicle. It's a shame how this all turned out.