Good news and bad news.
I've had Honda MTF in the transmission for almost two weeks and all my morning driveway coast-downs have shown a marked improvement.
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Unfortunately, I pronounced my air dam dead on Tuesday. Back to the stock bumper - which looks awful to me now, aesthetically as well as aerodynamically. The little bit of snow plowing the air dam did at the end of last week pushed it over the edge, I had multiple new fractures around the forward bracing and multiple fractures at the side anchors.
I think the key problem is that
PMMA EDIT: PETG has no business working as an air dam. Maybe it was okay in the summer, but I noticed it is way more brittle in cold weather. Also, I learned that the ABS air dam that I was inspired by (AndrewJ) was destroyed by 2009
http://ecomodder.com/forum/showthrea...tml#post105163.
I do think that my general approach in the end was not bad, with stiff material on top and more pliable material below. Quick thoughts on what would make this work better:
- Cut rigid material higher. 15 degree approach angle, or basically equal to the bottom of the bumper. Many cars can just use the bumper, it just depends on how backwards the slope of the bumper is aerodynamically.
- More durable stiff material, probably aluminum or steel sheet, but I think ABS would be fine if a 15 degree approach is observed.
- More comprehensive strip framing.
- More durable pliable material. Lawn edging does not stand up to repeated ground scraping, and I doubt that coroplast is a ton better. Conveyor belting seems like the way to go.
- The alternative to pliable material on bottom is a movable air dam. There's some verbiage in our state safety inspection that makes me think it would be an issue though.