"Modifications include a variety of components that increase the amount of fuel entering the truck's engine. When there's so much fuel that it fails to combust properly, 'it leaves the engine as soot,' according to an article on , a website dedicated to diesel truck owners," Grenoble writes. "That soot, which coal rollers call "Prius repellent" in online videos and forums and on decals on their trucks, can then be channeled up through 'smoke stacks,' where it exits onto bystanders (or a Prius following too closely) in a thick, pollutant-heavy black cloud."
One seller of smoke stack kits told the Post, “I run into a lot of people that really don’t like Obama at all. If he’s into the environment, if he’s into this or that, we’re not. I hear a lot of that. To get a single stack on my truck—that’s my way of giving them the finger. You want clean air and a tiny carbon footprint? Well, screw you.” (Read more)