[aerohead]

Originally Posted by ijames

In the GM patent (https://www.google.com/patents/US457...ed=0CB4Q6AEwAA) they show that adding the partition wall hurts performance several percent, but lets you have an enclosed lockable "trunk" - your choice.

I did a linear interpolation from a photo-enlargement of GM's drag table.
It looks like,that without the partition,the 50% cover gave a -Cd 0.0434 reduction.
With the partition,-Cd 0.0395 reduction,almost 10% difference.