View Single Post
Old 06-01-2009, 08:56 PM   #26 (permalink)
Ultimate Fail
Cd's Avatar
Join Date: Feb 2008
Location: Austin,Texas
Posts: 3,497
Thanks: 2,814
Thanked 1,058 Times in 644 Posts
Originally Posted by Deezler View Post
Yep Cd, we definitely think alike. Thanks! I was actually just down in my garage pondering a decklid extension.

The car is already super low though dude. Probably about 3" of ground clearance under the skid plate.

I agree on the VGs too. Worth a try for 20 bucks and the cool look, imo. I think the reason you (and me) are confused is that while they often tuft test well, showing better attached flow right behind them, or on rear glass, etc, we still have no idea what is going on above the boundary layer or further downstream. And in those cases where they do add frontal area, well, that might be more explainable. One thing I don't get is how people recommend to place them on the rear slope of the car such that they don't add frontal area. This makes sense in general, but if the air flow over your car is still attached where you place them, don't they still present drag on a nearly full speed air flow and thus add "apparent" frontal area? Ok, so not full speed air flow, but the same boundary layer conditions as you have further forward on the car in area that would add frontal area....?
I'm not the sharpest tool in the shed, as the saying goes. I like to hang out on this forum and pretend I can hang with the smart guys, and I see your point about the frontal area problem. What I had imagined was that the VGs would 'somehow' reattach the airflow like you see here Browser Warning without adding to the frontal area of the car by mounting them low and in the turbulent flow.

Who knows where the airflow is detached !
It may be attached all the way down the back window. ( Air does strange things sometimes ! )
It would be really interesting and useful to several folks here , as well as yourself, if you ( or anyone else ) could do a simple tuft test on the back glass of your particular car.

I really like what you have done with the mirror blockoff. That is by far the most professional looking job I have seen. I can't wait to see what you come up with next.

I want to clone your car
  Reply With Quote