Does e85 lower tailpipe emissions?
Would you see a diff if you swapped fuels, and did none of the above, probably but just as a FYI with some Roller Emissions testing stations here in the US. Is at some dealerships, other mechanics swapping fuel filter near the station have been known to throw off the machine so if you were to do it, I would suggest doing it farther away.
IMO too many varibles to say which would be lower. I do know throwing a bottle or 2 or rubbing alcohol will lower CO2 and HC and raise NOX a little but very helpful in passing these sometims PITA emission test.



