Reading some of the wind tunnel talk in another thread got me thinking about this story. I know it's been posted before but it's worth the read if you've got the time. I may be partial to the story as I'm from this general area and probably have been driving by this for many years without ever even knowing.
The secrets of Laurel Hill revealed - Chip's Secret
The rolling hills of Pennsylvania in the Northern United States hold a mysterious secret buried deep under Laurel Ridge. This highly classified test site is re-writing the textbooks on aerodynamic development.
The construction of the site took place in 2003 and rumours of existence first surfaced a year later.
Rumours of an abandoned highway tunnel being used by a racing team were the talk of the industry, but details were sketchy at best. Eventually Racecar Engineering managed to get hold of images of the tunnel in use which showed some intriguing modifications, including a large metal structure that has been added to the eastern end of the tunnel.
Tales recounted by hikers reveal a little more about what exactly is going on at Laurel Hill: ‘I had been hearing screaming burn outs and deep-tone V8s blasting through four gears clear from the top of the hill,’ claimed hiker Corey Shaulis, who took some of the pictures seen here. Discarded drums of Sunoco Supreme (a racing fuel developed for engines which operate between 7,000 and 10,000rpm and the official fuel of NASCAR) have also been photographed at the eastern end of the tunnel, and a new surface is clearly evident in some pictures, leading into and under the new structure. It all became clear somebody had built exactly what Paul Van Valkenburgh predicted in the March 1995 issue of RCE – a coastdown tunnel – a tool that combines the best elements of real world, straight-line testing and conventional wind tunnels.
Imagine being able to do limitless straight-line testing in perfect conditions – no wind, controlled temperatures and with a real, full-scale car. In the past this was impossible, but not any more.
read the rest here ==>
http://www.racecar-engineering.com/articles/nascar/the-secrets-of-laurel-hill/