This is a set of fairings that attempt to reduce drag for the Gen 1 Nissan Leaf. It has two parts:

• A fairing for the rear suspension cross-bar under the vehicle, which is otherwise a high drag triangle shape that sticks into the airflow.
• fairings for the aft edges of the front and rear wheel wells, to encourage attached flow. I tested with yarn tufts, and they do reduce detached airflow a fair bit behind the wheel wells.

In drift-down testing on a windless night, it seemed the under-fairing, wheel well fairings, wheel inserts, and removing the front mudflaps combined reduced drag about 10%, but it's hard to be sure, as there's a lot of error without an actual wind tunnel.

It will also help to fair the wheels better. In the photos you can see the slots of the alloy wheels are filled in by 3d printed inserts. However that varies by the wheel type. Search the net for these file sets, and use whichever fits your vehicle:

"Birdbone's avatar Nissan Leaf Aero Plates"
"Nissan Leaf alloy rim aero inserts (Leaf Petals)"

The suspension fairing comes in six parts, which should be glued together with cyanoacrylate. They're meant to be attached with two zip ties chained together at at least 4 points, with holes provided.

The wheel well fairings attach using the existing screws on the vehicle that hold the wheel well inner wall to the body panels. A handle to make a stubby phillips screwdriver is included that will make it easier. For the front fairing, it's a good idea to use 3M double sided tape to help secure the top of it, near the inner tab. Be sure to clean the surface first.

For wheel well fairings and wheel inserts, they're exposed to the sun, so it's a good idea to spray paint them black, then a coat of clearcoat. Also, print with PLA+ to reduce sun warping.

All parts were printed using a 0.4mm nozzle, with 0.2mm line spacing, 3 line wall thickness, and 8% infill.