Ziay!

tomchi

Or is it mostly for styling?

Nick N

On the bug, the spoiler really serves two purposes:

1) Visually differentiates the turbo model in a low key way

2) By disrupting laminar flow over the roof of the car, reduces the lift (rather than increasing downforce) generated by bernoulli's principle. It also keeps water off the rear window.

Joey is right in his assessment of most spoilers. You have to have a pretty big one to have any effect. My Evo's spoiler is a good example of a functional piece (it is homologated as a racing aero part). It's about a foot tall and has a flat airfoil. Even with a wing that size you don't really see an effect until around 60-70 mph, which is useful on a track but not really on the street. I make my spoiler useful by driving it on a track .

Useful aero pieces on production cars usually take two forms, either a tiny lip on the trailing edge of a car (reduces drag and lift), or a giant wing (which should be flat, curved wings are not as effective), which increases downforce but also increases drag. The Beetle's spoiler is really more of a lip than a spoiler.

NickName

For the majority of mainstream cars, spoilers end up being mostly for show. However, if you're a bit of a lead foot, they can actually do some good. Depending on the type of spoiler, its size and the placement of it on the car, it could help a bit with handling and, although very minutely, could also improve gas mileage in the long run. Spoilers create downforce by directing the airstream the flows over your car at speed. The higher your speed, the more downforce is created. Typically, spoilers don't really do much benefit at speeds lower than 55-60 mph (Always observe posted speed limits!).

I don't claim to be an expert but I have been an avid car fan for 20 years. Hope that helps.