Peter wrote:
> Except the high pressure areas are under the car (unless using 
> spoilers to prevent that) and in the shockwave behind obstacles, and 
> they are not flush with the body. The air scoop must be raised out of
>  the boundary layer to work well. Some F1 cars have a huge yacht-like
>  wind scoop air intake. That works well probably.

   Cowl induction hoods do stick up into the airstream (2"+).  NACA ducts
are the ones that don't.

   NACA duct: http://www.racerpartswholesale.com/naca.htm

   Cold air induction systems have been shown to pick up a few tenths of
a second in standing start quarter mile runs.  David Vizard [1] gives as
an example the factory installed cold-air ducting on certain early '80s
Z-28s as being good for about a two tenth of a second reduction over an
open element air cleaner.  Nothing fancy, just a few large tubes run up
to the front bumper area and plumbed into the air filter box.

   That's like putting the car on a ~200 pound diet so it's easy to see
why it might justify some experimentation.

Tad Anhalt
[1] Writer of various performance-oriented books:
"How to Modify your Mini"
http://www.aptfast.com/APT_Parts/Books/Book_Info/B-123_info.htm
"How to Build Horsepower"
http://www.amazon.com/exec/obidos/tg/detail/-/0931472245/ref%3Dpd%5Fsl%5Faw%5Falx-jeb-9-1%5Fbook%5F4676307%5F3/102-0536218-0752142
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