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Old 06-09-2011, 02:58 PM   #5 (permalink)
California98Civic
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Join Date: Mar 2011
Location: Coastal Southern California
Posts: 6,299

Black and Green - '98 Honda Civic DX Coupe
Team Honda
90 day: 66.42 mpg (US)

Black and Red - '00 Nashbar Custom built eBike
90 day: 3671.43 mpg (US)
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Quote:
Originally Posted by euromodder View Post
On Volvo sedans (S60/S80/S40 Mk.2), you can see the higher trunk line toe in as it gets further aft, reducing the wake area of the upper half of the car.
At the same time the higher trunk line reduces the apparent rear angle, so it'll match the streamlining template closer.
Cd and euromodder, thanks for your comments. I made changes based on Cd's earlier ideas. Mostly changing to all coroplast and cutting a more contoured line to try and avoid drag. But I now think I might need to do more. Any ideas that don't involve tape to the body? The plan is to make it easily and quickly removable (magnets). I also plan to taper more now, based on these ideas from you, euromodder. Here is an update and a hope you and others might further advise:

I tested the below design (see pics) last night in a situation of low traffic but dropping ambient temps. My not-so-reliable results suggest a possible gain of .65mpg, or no gain at all, but no loss likely. I need to retest it, having learned not to test between 10pm and midnight. I found MetroMPG's old excellent tuft testing for his vortex generator experiment, and I plan to copy his spacing and length of tufts. I'll try and build this vertical tuft thing too, Cd. I'll take and post video.

But first how might I improve the tapering, the trailing edge, and other drag contributors. I should curve the ends of the "lip"?
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See my car's mod & maintenance thread and my electric bicycle's thread for ongoing projects. I will rebuild Black and Green over decades as parts die, until it becomes a different car of roughly the same shape and color. My minimum fuel economy goal is 55 mpg while averaging posted speed limits. I generally top 60 mpg. See also my Honda manual transmission specs thread.



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