2016 Duramax vs 2002 Duramax Mashup

I always wondered if it was better for the environment to place all these emission controls on a truck which forces it to use more fuel per mile than a truck with no controls that uses less fuel per mile. What is more harmful to the environment over the long haul ?

Probably a more accurate method of comparing fuel economy is put 10 gallons in a dry gas tank and run it till it quits and see how many miles you went.