The top cowl piece has small winglets that are part of the aero package. The DeltaWing doesn't have a rear wing, perhaps the only race car in years not to have a rear wing!
The winglets are dual plane and are adjustable in pitch. They are mostly to fine tune the car's aero balance rather than to contribute a large share of downforce.
Here is another look of the BLAT vortex generators. You can see how they can generate and contain the strong side vortices.
The flat lower plane of the BLAT aero can create a lot of downforce with minimal drag. The BLAT effect really works well on a car with a narrow front like the DeltaWing, in fact the concept works a lot better in the DeltaWing than the original AAR Eagles. A funny note is that Dan Gurney made up the BLAT acronym because he thought it was funny like a fart noise.
The DeltaWing has progressed from a weird looking backmarker to a car that turns competitive lap times and has led several races. A couple of races that looked like sure podiums were prematurely ended by transmission failures.
The DeltaWing lead several laps at the LBGP.
Once the Elan team can solve the transmission issues, look for the DeltaWing to be on the top of the podium. We feel that this will happen sooner rather than later. With its success will the DeltaWing concept become the norm in race car design? Will less equal more?