Orciari Rear Spoiler

T

his had been sat in my home office for a couple of months, but right after a trip to California, I set about arranging to have it sprayed and fitted to Kermit.

Well what a project this turned out to be! The Orciari spoiler looks very stylish, in my opinion, but the unit is not quite a perfect fit to the Ka’s tailgate. And this meant that it took a lot longer than anticipated.

Not quite a perfect fit? Okay, so the fit is nothing like as good as it should be, and required a lot of hard work by myself and the bodyshop. The rear brake light doesn’t quite fit it properly, but at least the wiring works!

I’m also a perfectionist: I’ll know that the rear spoiler isn’t a perfect fit, so forever will I be seeing the faults, not the natty spoiler on the back of the Ka. However . . . I am also quite pleased with the result! It’s small enough and subtle enough that some people don’t see it at all, which keeps me happy.

Kermit’s Spoiler Position

If you have a good look at Kermit’s spoiler, you’ll see that it protrudes from the boot.

This was a deliberate thing: I wanted the spoiler to protrude ever so slightly so as to actually do something else rather than simply hold our high level brake light.

A proper spoiler is designed to either produce or relocate a pocket of turbulence. Turbulence is a “swirl” of air that reduces aerodynamic efficiency by sucking at the back of the object. It’s turbulence that causes water to be sucked on to the rear windscreen when driving along a wet motorway.

Fluid dynamics show that the most efficient shape for a small car is to have as straight a back as possible – think Fiat Cinquecento – since this produces a pocket of turbulence right behind the car, where it has the least impact. If the object has a curvy bottom, the turbulence created is rather larger and it has a greater area to act upon.

By positioning the spoiler slightly higher than the edge of the boot, I’m forcing the turbulence slightly higher and away from the rear windscreen. The theory behind this is that it would reduce the amount of water being sucked back on to the windscreen of the Ka when driving along on a wet motorway – and it works!

Standard rear spoiler positioning on modern hatches is more about looks than anything else, but if you study cars such as the mark two Fiesta XR2 you’ll see that the rear spoiler has a lip that sticks up at the trailing edge.