This weekend I mostly spent time "finishing" or redoing previous aero projects:
- New coroplast upper grille block. Painted glossy black, it looks pretty cool, even if very imperfect. Hella better than the cellophane!
- New coroplast lower grille block. Improvement upon duck tape.
- Accessible tire valves (!)
- Plugged the tunnel under the spoiler with thin acrylic.
- Underside wheel well dam
The most important mod was obviously the tire valves. I finally pumped up my tires, which were 10% low!
The upper grille block is nice. But now that I'm no longer covering the whole front with a piece of cellophane, it's much more leaky than it was. I might try some black caulking around the edges, which could also help the looks by covering the coroplast edges. Eventually though I'd like to upgrade to something that looks nicer to begin with, like ABS.
The lower grille block is taped on with "double-duck" and folded under with zip ties. I think it may be adding drag, because I had a lot of difficulty curving it around flush with the bumper, and I ran out of anchors for the zips.
The accessible tire valves are basically the same as on
Concrete's pizza wheels. To get enough protrusion to be usable, I had to stack two extenders on top of each other. I have to wonder how much turbulence is added by having those valves revolving at high speed. I might consider instead making the hole bigger but leaving them under the wheel covers.
The clear spoiler-tunnel wall seemed sturdy enough on the drive, despite being only 1/8" thick. I don't think there's a lot of air trying to scoot under the spoiler, which probably means this won't make any difference. I made it out of one 7-dollar 18x24" sheet, with a 24" center section and wings on either side.
The underside wheel well dams are an experiment - though obviously not a very scientific one - trying to prevent air from getting into the huge wheel wells from below. Because the wheel has to turn, it's not easy to make the belly screen any closer to the wheels. So with some spare coroplast, I made a front dam under the car, mostly above the lower line of the bumper. I have no idea what kind of effect to expect from this mod.
Performance: No great news to report. On my morning commute the ScanGauge told me 30.1 on a new calibration that is giving a slightly low error in miles-driven, and suggests a 30.6mpg commute. I can't yet confirm that my beginning-of-the-week readings are low, because there have been anomalies. I am sure, though, that the car is taking longer to warm up in the morning, and my getting-out-of-town marks are lower - but I haven't kept track of that well enough to know how much.
I did however expect more of a jump after the cab and bed mods, especially now that I pumped my tires. There's probably something dragging. I look forward to the day when I can finally do some science and sort out the effects of all this stuff.