So, after a week of having the new air dam on the car and several drives under my belt, some observations:
- I've scraped it on bumps & driveways maybe 3 or 4 times. That's much less than the one I had on the Civic (3.5 inches clearance vs. 5). Have you seen the OEM air dam height on the Chevy Volt? They must scrape a lot.
- My Extremely Scientific and Accurate Butt-o-Meter says the car coasts further and my Non-Confirmation Bias Seeking Eye says the ScanGauge seems to be reporting better MPG at steady speed.
I was able to make a MPG comparison of a pre-air dam vs. post-air dam round trip...
- 76.8 mpg US (no air dam) round trip (87 km / 54 miles)
- 82.5 mpg US (air dam) same round trip
And that was
with a 3.2 km/h (2 mph) higher average speed with the air dam on (low 30's avg mph; max of low 50's; cruising between 45-50). Similar weather & traffic conditions (mostly deserted country roads with more than a few stops & turns).
Big disclaimer: unfortunately I changed another major variable to confound these results because I
also put RE92 low rolling resistance tires on the car in between the two trips.
I think I may do an A-B-A of this air dam though. It seems like it may show up above the normal noise of testing variability.