[California98Civic]

I tested my spoiler on a 6.2 mile stretch of freeway this evening. I got to speed (55/56mph) and throttle position (16.5) before pressing reset on each run. I held 16.5 throttle throughout, allowing speed to fluctuate on hills.

I made A-B-A-B runs. Each "A" and each "B" includes a trip 6.2 miles north and another south. Average of all "A and all "B" runs:

A (no mod) = 49.55
B (modded) = 50.15

Attached below is what the spoiler looked like during the test.

PROBLEMS: The test was not ideal. A modest crosswind kicked up in the middle of my runs, and I seemed to attract trucks like a giant magnet on a few runs, forcing me to eliminate an outlier run completely and repeat it. Also, despite being on the freeway, hills and my throttle position meant that my speeds dipped to 45mph once in each direction. Often I was driving 52/53 mph. Those are speeds not much better than my earlier 52mph quickie tests. But I was often in the 60-65 range too. Lastly, a small part of the underside support (seen resting on the bumper in the photo below) got ripped-off by wind on the last run, which makes me wonder about vortices and such *under* the spoiler. Who knows...

These results largely confirm my quickie tests on previous nights, and even suggest that higher speeds would still mean greater benefits for FE. But this is a big, long spoiler! Two feet extension. Seems like a too-marginal gain for such a conspicuous mod.

I want to try a smaller design, with a mild, upward angle of a few degrees. I don't think I want to build anything more permanent in this form, for these gains.