Not sure how far I'm going to take the aerodynamics on my Cavalier, but I'm sure it will be a lot more than if I hadn't seen this site and the work Basjoos has done.No shortage of imagination here I see. Of Course if I payed 50K for a prius I'd be a little slow about mods too. ( shock therapy is a little out dated anyway )
50k for a prius????
don't waste your time or time will waste you
My only questions are in regards to the underside of the boattail - have you tested with and without? With mpg meter or tuft testing? I'm not sure that an angle as extreme as that of the top will work (which it appears like it is, correct me if I'm wrong), because the air filling into the gap on the bottom must come from only the sides, as the bottom is road and not a whole atmospheres worth of air. Which is why you see that most solar cars have a flat bottom.
Like you I am noticing the difference in maintaining speed on coasts, increase in terminal velocity on particular hills, increased apparent power at higher speeds, lower throttle required to maintain speed. And I'm also noticing that I'll be about 100km past where I used to have to fill up.
My car also probably generates more conversation and stares than your average Ferrari. I gather this is the case for you too.
I went with a sharper than optimum angle on the bottom of the boattail for 2 reasons. I have a steep driveway entry angle and didn't want to drag the boattail bottom when entering it. Secondly I didn't want the boattail to extend more than 4 feet beyond the back axel to keep the tail from sticking out too far on the outside when making a sharp turn. If I went with a shallower bottom angle on the boattail, I would have had to extend the tail for another foot or two beyond its present length. The solar cars can get away with a flat bottomed boattail since they typically have very little body height to have to taper down from.
I typically get lots of gawkers and photos taken where ever I drive.