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Old 06-13-2013, 04:32 AM   #15 (permalink)
Xist
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Chorizo - '00 Honda Civic HX, baby! :D
90 day: 35.35 mpg (US)

Mid-Life Crisis Fighter - '99 Honda Accord LX
90 day: 34.2 mpg (US)

Gramps - '04 Toyota Camry LE
90 day: 35.39 mpg (US)

Don't hit me bro - '05 Toyota Camry LE
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Quote:
Originally Posted by ennored View Post
Phil had posted some Cd reduction vs. template percentages somewhere. I copied them and other info into a spreadsheet. Assuming a three sided, flat bottom tail, the transom reduction doesn't follow the Cd reduction. And suggests even a short tail has the potential to make some pretty substantial improvements.

% Template Transom reduction Cd reduction
0 0 0.0%
10 2.1% 23.2%
20 6.2% 38.7%
30 14.3% 50.8%
40 25.8% 60.2%
50 40.0% 66.8%

Crude math, lots of assumptions, blah, blah, blah....
Ah right. That!

I guess that making the air detach cleanly is worth 11.6% better MPG, because the improvement is huge, compared to the transom reduction!

I love math, especially when I am supposed to be doing something else (I wonder if I already did this somewhere):

% Template Transom reduction Cd reduction Additional increase
per segment per segment per segment
10 2.1% 23.2% 23.2%
20 4.1% 15.5% 12.6%
30 8.1% 12.1% 8.7%
40 11.5% 9.4% 6.2%
50 14.2% 6.6% 4.1%

Those are some diminishing returns!
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