[19bonestock88]

I did vortex generators on the Malibu that I had and water tested the back glass before and after... I copied the formula from the Evo, and had them about 4” above the glass... beforehand, there was flow separation in the center of the glass, that showed itself in water(dew in the morning) taking forever to run off if at all on my commute... after I added the vortex generators all the water run off as soon as I got up to 50mph, but I couldn’t detect any net improvement in drag... it took the same(or within a window of error) throttle/load to hold 55mph on flat ground as it did beforehand... now I never did a true coastdown test to produce more accurate data than just engine load at cruise, but eventually I removed them(after two tanks I think) both because I didn’t think they were helping and because my then wife was starting to refuse to ride in the car...

The visor isn’t a half bad idea(might use on my build), and they can be found for $30-50 for the Civic... a shame I can’t get one made specifically for my car, I’d have to cut up one for a Corolla or something... like mentioned earlier, cut a slot near the leading edge(about 2” wide(est.) and almost as long as the whole visor) to allow an air fence and I’d really think of using thin Plexiglass to extend the trailing edge to about where the trunk lid comes up to when open... if you follow the template shape, it *should* help