This is ridiculous for so many reasons. If it’s fake, which I think it kind of seems like it might be, it’s really dumb. If it’s real, then the owner of this truck is the biggest asshole in the world- to himself. Maybe it’s a nice way of reminding himself to drive slow to conserve fuel, because nobody wants to get a face full of particulates every time they accelerate from a light.
I suspect that the stack is not real because how in the hell would that thing stay sealed? There must be some way to open the hood, but the pipe looks to be welded (very pooly) to the hood of the truck. I looked behind the truck and didn’t see any signs of an exhaust system back there either. And I’m sure it’s not an air intake, because of the flap.
I really don’t know what to think. In the end though, it’s your own vehicle and you can do whatever you want with it. I really just ought to be thankful that this guy driving this truck means there is one less person driving a 240sx with mustache print duct tape on it out there in the world.