Anybody know the difference between a 2-pipe air injection vs a 1-pipe air injection? 10-15 years ago I chucked a bunch of 2-pipe air injection stuff I never thought I’d need... this was a mistake. In Colorado, the full air injection system is a visual requirement for registration. I found part of a 1-pipe system now. Wondering if I should rebuild the 2-pipe version of go forward with what I found locally. Thanks.

 

MYTH/FUD, ;-)
It's not a state requirement it's based on your residential location (county, and even that has some fudge factor)..

I digress!

The two path system is older tech than the single path, unless I've missed something, so your vector with the smog.tech is "I'm using newer tech/system than is required by my Vin date."