I thought the percentage of harmful emissions coming from the draft-tube were/was higher than that.pdq67 wrote:EPA found out that about 34 to 35 percent of car smog emissions produced came from the draft tube with the rest coming from the tailpipe and the carb. and gas tank filler cap.
Any way I look at it, PCV was the best thing that ever happened to the automotive engine. Less internal contamination, longer bearing and oil life, less harmful emissions, safer roads (not oil-slick from draft-tube residue.)
I'm old enough to remember concrete roads that were absolutely black between the typical wheel paths. And Driver's Training hammered into the students about slick roads at the start of a rain shower--the rain would lift the oil from the center of the road, spreading it into the tire tracks.