rear wing thingie?, does it do anything? Options

[shaggy]

ive seen a few pictures of 914's with this small rear spioler wing thing on the rear trunk lid

do those even create any down force?
is that down force that it would create necessary?

are they coustom made?
where would i go about getting one if they arent?
those things look pretty cool

[maf914]

Aerodynamic effects are not always easy to predict. Read a few books on auto aerodynamics and you will see that rear duct-tail spoilers mounted on a flat deck lid can do different things. The basic idea is to catch the airflow across the rear deck and generate a positive pressure over the rear deck which results in downforce. Within limits, the bigger the spoiler the greater the air presure. In the past before NASCAR went to common templates the Pontiac teams always complained that because their rear decks were shorter than the Chevys and Fords they ended up with less downforce for a given spoiler height. On cars where the rear airflow may be separating going over the rear roof and deck a rear spoiler can have the effect of raising the body work and allowing the air to remain attached, reducing drag. It all depends on what the air flow is doing with a particular car.

Wings are more efficient, but spoilers have been around since the sixties sports racers. If you look through some of the historical books on cars such as Chapparal, Ford GT, Shelby Cobras, or the Can-Am McLarens and Lolas you can see how the designers were trying to figure out how spoilers, front and rear, really worked. Modern sports racers like Audi R8s and Lola's don't use exagerated spoilers like they did in the past, because they try to find downforce in more efficient ways, but you can see Gurney flaps (small spoiler lips) used in many locations.