Just for kicks, I was comparing the xD to the xB2 on the EPA's website, and noticed something striking.

The xB2, having lower gas mileage has a 17% higher carbon footprint than the xD. BUT, the xB2's pollution score is 6 (higher is better) while the xD's is 3. Upon further research, the xB2 meets ULEV-II requirements, but the xD only passes LEV-II. Side by side, the xD essentially pollutes 2-3x in some categories while equal with the xB2 in others. Overall, the xB2, despite being larger and using more gas, pollutes less than the xD.

Just interesting info.

 

hmm wonder why that is? Does the xd have two cats like we do?

 

woo xB2!!!!

 

the xB2 puts out more carbon dioxide but the xD emits more smog producing polutants. fueleconomy.gov has these ratings

 

Keep in mind it is most likely in regards to percentages, and obviously a smaller engine is going to put out less smog at any given percent than a larger engine, so yes, the percent on an xD might by higher than an xB2 but in the end, it might in fact be less. Who knows.

 

no it is not based on percentages. It has to do with the kind of emissions. Teh scale shown on fueleconomy.gov is used for all cars and it is not relative to the size of the car/engine. It is a rating of how it polutes compared to other cars. That is why the xB2 is ULEV and the xD is LEV. nothing to do with percentages.

The xD might emit less CO2 but its carborators do not trap as must of the smog causing particles. There was a thread about a guy in texas trading his old car in for a new car. Texas gives a tax credit if you go from a 10year old car to a new low emissions vehicle. The xD did not qualify but the xB did qualify as low emissions

 

I guarantee you that if you take two cars, with two different engine sizes that had the same exact smog output, I would be willing to bet $100 that the larger engine would put out more smog than the smaller engine. And by the way, the xD and xB2 are fuel injected, they don't use carbs. hehe

 

oops yeah i meant to say catalytic converter not carb.

The rating system called the EPA Air Pollution Score rates what comes out of the tail pipe. It doesnt pro-rate it for the engine size. Therefore is one car has a smaller engine and scores worse, it actually creates more smog forming polution than a car with a bigger engine. Here is what they have to say
http://www.fueleconomy.gov/feg/airpollution.html

Scion xD ranked at a 3 (worse) for air polution
Scion xB ranked at a 6 (better) for air polution
xD produced less greenhouse gases than the xB due to its smaller engine. But produces more smog.