Ok got an Idea I want 2 try
 

I see where Im probbably not getting much effect from rear spoiler due to sedan with a trunk.
How do yall feel about about a crescent shaped extension attached to and protruding from top of the trunk back about 15"+/- 2".
I can trim it out of 20 gage steel so it will be strong enough to not flex down or up while providing flow separation over pressure stream from vaccumed cavity behind and below the trunk.

The crescent shape is to keep the unaware from walking into it and being hurt and hopefully to first mix blended side and upper side pressure stream from window height into vaccume cavity behind car slightly b4 the over car decompressing Air stream further entangles it.
Im just trying to reduce the parachute effect slightly because of side skirts and front spoiler.
I really wish I would have just went with full belly pans.
I hope someone can actually understand my description.

I have seen inverted spoilers on stock cars doing a similar effect where it sorta starts at mid tire height on trunk and sweeps up and back for 1-2 feet for blanket separation .

anyone ever gone here?????

i have that simular on mine if understand you correctly. will look for a pic.

What you appear to be proposing is a roof spoiler.

I would suggest a roof wing which provides a leading edge air slot that directs air downward parallel to the rear windshield.

This air will be (because of the restriction) accelerated and of lower pressure than the air above.

The air above will be drawn down to fill the void below it.

I've done this to my pick-up truck cabin, and seen something similar on a Scion recently.

It is unconventional, but that's what this forum is all about, right?

Aerodynamics Photos by kach22i | Photobucket
http://i184.photobucket.com/albums/x...ps2aca4365.jpg

http://ecomodder.com/forum/showthrea...1-a-19525.html

hmm
 

I was really trying to be a cheap skate and avoid junk yard back glass type spoiler. where the translucent arrow point is at was about where I wanted to end the crescent shape just to be a stream continuation divider.
Are ya telling me it will be ineffective because it will overshoot b4 boundry layer even starts to recompress???
I think your probbably rite so please dont feel like im argueing I just wanted to get out cheap. I really do h8t this car and envision myself soon in new mustang. This darn thing dont die. just keeps rolling it breaks and usually results in me removing another 2-10 pounds of parts. LOL.
Yeah so ill look at u pull it this weekend.

Some drawings, diagrams or example projects other's have done will facilitate the discussion.

I have my mind on other things at the moment - sorry.

I interpreted your description as being a 'Bonnevile' spoiler. They lay flat instead of being angled upward to provide downforce (with it's aerodynamic cost).

http://ecomodder.com/forum/member-fr...studebaker.jpg

http://ecomodder.com/forum/member-fr...bonnevette.jpg

http://ecomodder.com/forum/member-fr...ture5476-9.jpg

Instead of a cresecent shape, endplates with diagonal day-glo orange stripes?

What about something like this?

http://i1289.photobucket.com/albums/...ps528a93d1.jpg
http://i1289.photobucket.com/albums/...ps86349721.jpg

But with the 'wing' protruding out further to direct flow towards the top of the trunk/spoiler.