Hatch Wing on 2009 Toyota Matrix
 

http://image.motortrend.com/f/photo_...+rear_view.jpg
http://www.motortrend.com/roadtests/.../photo_01.html


Is this little rear wing going to help or hurt the cd?

It looks like the spoiler is higher than the roof. If this is the case then it is bad for aero.

If you look at the 03-07 Matrix you can see that the spoiler on it follows and extends the taper of the roof line. That type of spoiler helps aero.

Very true, but this one is aweful for FE:

http://www.polyshineauto.com/GRAPHIC...atrix-2003.jpg

The hatch on the new Matrix is more sloped than previous years. A spoiler like this probably helps since it break the airflow away from the body in a straighter line. That usually helps Cd.

hurt

It would probably help if the spoiler was slightly modified so that its angle would slope downward as the same angle of the rooftop.

upswept rear wing
 

Hurt.

So far, the 'Hurt' vote seems to indicate that Toyota made a mistake on this one.

To this total novice aero DIYer, that looks like a wing for putting down pressure on the rear wheels. At the cost of a lot of drag.

edit:
Good news. I checked their site, and the "Hatch-mounted roof end spoiler" is not standard on the less expensive versions..

drag
 

The Matrix body type does not generate lift.So since the up-kick on the wing would generate downforce,that type of wing becomes a solution for a problem the Matrix doesn't have.My guess is that it's a "Rally-inspired" concession to styling.If they make one ( as others have mentioned already ) that follows the original roof and side contour,that would be the one to go with.

How do you know for sure it doesn't generate any lift? The profile resembles a wing shape to me. Anyway, the problem here is the perspective of the photo. It's shot from ground level giving the appearance that the spoiler tilts up. The rear edge actually winds up horizontal, or parallel to the road surface; which is what you want when breaking airflow away from the body to reduce drag.