I was thinking this morning - wouldn't this be a very easy mod that would pretty much ensure that any car would pass a smog check?
(I'm not suggesting doing this, it may or may not be legal, just curious if it would work)
1) Weld in a bung (like an oxygen sensor bung) in the exhaust system somewhere. Maybe right before the muffler.
2) In normal use, just have it plugged with a bolt. But for a smog test, hook up a hose to it, hooked up to a high volume electric fresh air pump.
It would seem that any fresh air pumped into the exhaust flow would pretty much reduce NOX and CO2 on a 1:1 basis, i.e., if the exhaust flows at 350 CFM and you "inject" fresh air at 350 CFM you'd cut down measured emissions in half.
Would it work?
