[aerohead]

Originally Posted by Tygen1

So heres the results.

Spoiler was set to 30 degrees, with an angle of interception to the roof of approximately 13-14 degrees

Conditions: 30 degrees F, 30.17 Baro, 33% Humidity, Winds NNW 9mph.
No wind on route, unless noted, road is surounded by trees. Starting Speed Was 70mph, then coasted down to 30mph. Runs were started in the same place, unless noted, going each direction, road is not flat. All runs ended in approximatly the same place as well.

First Coast Down Run going West with Spoiler:
West, 53.7 sec.
East, 1.00.2
West, 54.6
East, 1.00.3
West, 59.6
East, 1.00.2
West, 57.4

Now without spoiler going East to start:
East, 101.1 sec.
West, 102.2 (tailwind, enough to blow a flag by the road)
East, 101.5
West, run spoiled by someone deciding to park in the road
East, 103.4
West, 59.4
East, 102.6
West, 55.0 (started and ended in a different spot due to "traffic")

Now with Spoiler again.....wait....whats that sound, thats the sound of the spoiler getting ripped off at 65mph, should have put on more tape! Made two runs without knowing it was off, then drove under a street light and noticed it wasn't there. The next half hour was spent in the dark looking for it. Ran out of time and couldn't finish. Either way, these next two numbers are without bias, because I thought the spoiler was there and it was not, but I did have a lot of flapping tape
East, 1.00.1
West, 55.7 (started in the same place as noted above)

With some creative droping of highs and lows to account for the inconsistancies I get 58.06 sec. with Spoiler and 60.41 without spoiler. It would seem the spoiler did not help in this configuration.

Edit: Some notes after some pondering.... I believe the West bound times are as inconsistant as they are because I did not have land mark to reach 70mph by and therefore had an inconsistant start point and because it was a bit hilly, the ending point on the West Bound coast down was an up hill. So we could just drop out those times and just look at the East Bound times. If we do that we get a 1.5 longer coast down time with the spoiler vs. 2.35 as I calculated it before.
I also noticed that quite a bit of dust had accumulated under the spoiler, in just one hour of driving. So this leads me to believe that it just increased the size of the wake.

I believe the next steps will be some tuft testing to see what the air is doing on the trunk lid and I'd like to try a horizontal extention to see what effect that has. Also need to try and find a better road to test on.

waiting on some feedback from you fellas...

Tygen1,I know you're working with what you've got and we all appreciate you testing and sharing .
And not to create work for you but let me throw out the following and see what you think.
First,your temps are just within bounds for what SAE would recommend so that's okay.
Second,SAE recommends that the rest road have no more than 0.50% grade.I think those hills are beating you up!
Third,if you will "start" your paired return run in the opposite direction where you "finished" the original pass,you'll be covering the same surface for both E-W runs and "cancel" any uphill/downhill the car might have seen.

The dust behind the spoiler is a GOOD sign! It means that the separation is behind it.Your original wake is as high as your roof.
Your tuft test should NOT indicate attached flow in front of the spoiler.There will only be an attached vortex trapped between the back edge of the spoiler and the top of the roof with a sideways tornado spinning in between.
It's this vortex which is giving you the drag reduction.