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Old 08-29-2014, 01:54 AM   #13 (permalink)
2000mc
herp derp Apprentice
 
Join Date: Oct 2008
Location: Lawrence, KS
Posts: 1,049

Saturn-sold - '99 saturn sc1
Team Saturn
90 day: 28.28 mpg (US)

Yukon - '03 GMC Yukon Denali
90 day: 13.74 mpg (US)
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Quote:
Originally Posted by cowmeat View Post
You can make them lower, bro! They probably don't cover enough real estate to do much as-is. Black Widow's are fully horizontal, and they come within a half inch of the rear tires. The trick is to flare them out ever so slightly at the bottom, which is accomplished when you attach the front and rear lowest screws/clips.unfortunately the length is a limitation i do want to impose on myself. i'm pretty sure i'll be able to take the tire off without removing the skirt at this height. i also thought it was near the height used on the ev1, so i was hoping it would be good enough for a sc1

I would test them for a full tank, that'll give you a better idea if they are going to be worth permanently installing. If you're questioning your instant read-outs, there's nothing like a full tank's mpgs to average all the conditions out. i just dont have consistent enough tanks for this

I don't have any instrumentation, but in all honesty mine really don't make much of a difference, maybe because my wheel wells are smaller than the average car's. They definitely get people talking about the car, though! My installation is on here somewhere if you want to see how to NOT do it, lol!


Quote:
Originally Posted by oldtamiyaphile View Post
If SG testing isn't conclusive, it's time to move to coast down tests.
im thinking that will have to be my method next time around. if nothing else, it requires less fuel

Quote:
Originally Posted by RedDevil View Post
The skirts need to be really stiff to work right.
The cardboard does not look very rigid, esp. those 2 vertical folds. If it deforms or vibrates that will reduce its effect big time.

Cardboard is usually much stiffer in one direction than the other.
The central layer forms a wave shape between the outer layers, creating channels in between. It bends easily parallel to those channels, not so across them.
I suspect you used it in vertical orientation (the folds seem smooth, like they'd be when folded parallel with the channels)

If you do a rerun with horizontally oriented cardboard skirts that may show better results. Make it a double layer just to be sure.

Even if it works I'd expect a reduction in fuel consumption of about 1 - 1.5 %.
It will be hard to prove it does make a difference.
i had thought about this when making them, and the channels within the cardboard are horizontal. the 2 vertical folds are because its the top and bottom flaps of the box they were made from. the skirts were 31" long, so they were the best chunks i had around. i thought they were actually surprisingly stiff on the car, i think the most helpful thing was overlapping them onto the body 1 1/2 - 2". i dont know if i would have been able to tell if they were flapping or vibrating during the run, but with just some standard masking tape holding them on i would have thought i woulda lost one, or have one atleast come loose on the end after roughly 20miles at 65mph


so my current idea moving forward is that maybe there is alot of air moving out through the wheel well, and that from the view of the car from the underside, my rear wheel wells are more like parachutes now. to try to fix that im thinking to try rear wheel spats, that depending on what things look like from the underside of the car, might extend a bit further inward to try to keep air from blowing up into the wheel wells.... if they help, then adding the skirts back might show a greater benefit
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