Better Fuel Economy at Freeway Speed

The question relates to extension of the rear wing. The manual states the rear wing automatically extends at 75 mph presumably to optimize the handling of the car at this and higher speeds. The rear wing probably acts as a spoiler I guess which should reduce the drag caused by turbulence in the airflow at the rear of the car. Would manually extending the wing improve drag at 65-70 mph which is the posted speed at most freeways?

Not sure it reduces drag so much as it creates a downforce. In fact it may actually increase drag as a compromise for improved handling, hence the reason it is not up all the time.

I agree, it probably increases fuel consumption if anything due to higher drag.

Once you go above 75 it will stay up till 50. Very rarely is the freeways moving below 75 around here. As to drag I would say that keeping it down would be the best. Remember more downforce more drag. But I would just leave it alone and let it do its thing. You would also probable need a wind tunnel to see any difference at MPH.

In terms of aerodynamics, it looks like it's very similar to the Audi TT. Apparently, I've read about the TT and the 911 (without the wing,) in that since their profiles are very much like airfoils, without a wing and at speed, what happens is that when they brake hard, the front end dips down and the car actually lifts a little bit having nor rear traction. Now imagine doing that before a turn, and I've read in past articles that these cars could "lose it" if there were no wing. One of the reasons why the 911 has the whale tail, the Audi TT comes standard now with a spoiler, and I'm guessing, the Cayman has the retracting wing.

No, I think I read the "wing" on the CS acts as a true wing with measured downforce in so many pounds ... ~45/50? On the other hand the wing on the Boxster S IS a spoiler that breaks up the air stream. There is a difference.

From the way the parts are configured, when down, the wing acts as a true spoiler, reducing turbulence producing some down force - when it's up, together they become a two-stage spoiler and wing arrangement adding additional down force. I can't find the material, but I thought I read someplace that the down force isn't all that much - somewhere in the 40-60 lb. range - but enough to help the rear end stay on the road better at high speeds. More down force = more drag, which = less gas mileage. brad

I've read this multiple times, its a true wing when up and not a spoiler like the Boxster while researching for the FAQ. I believe its about 50 pounds where the Exige is somewhere around 75/80 pounds. Not clear what its doing when down, at least from the literature. At the rear this strong downforce is mainly a result of the new split wing moving up approximately 80 millimetres or 3.15” as soon as the car exceeds a speed of 120 km/h or 75 mph. Contrary to a spoiler of the type to be found in the Boxster, a split wing of this kind keeps air resistance to a minimum while generating powerful downforce through the specific angle of the wing. http://www.seriouswheels.com/cars/top-2006-Porsche-Cayman-S-Production.htm "... at the rear, the Cayman S has a pop-up wing instead of a spoiler. Because it is specially shaped and is higher – 3 inches above the body - it gives more downforce, http://www.coolsupercars.com/2006-porsche-cayman-s-2/

Whats the difference between a wing and a spoiler?

A wing allows air flow under it and looks in profile like an airplane wing. A spoiler is connected to the body all the way, think of a NASCAR car.

I see! What are the benefits and negatives of each? Dont want to further hijack the thread,ill pm you busman.