Rear kammback spoiler

[California98Civic]

The black plastic, or blackened glass in some cases, is just the exterior where the back pillar is. For some reason, it is in plastic or glass instead of steel. Maybe for glass replacement ease. Anyway, you are right, it makes a convenient mounting point. I wonder if the plastic mouldings could be removed and their mounting points used for a spoiler. I wonder if substntial amounts of double sided trim tape could be part of a mount to glass.

[JulianEdgar]

Originally Posted by eagle

also, here is a rear windscreen from a renault scenic with -a quite big - side spoiler which also has these...uhm....holes?

It looks like a normal separation edge. If the holes are real, they may be for the cabin ventilation outlets.

[freebeard]

Speaking purely from a speculative point of view; that appears to be a perfect location for a Coanda nozzle: