Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - Aerohead's going to the wind tunnel! We're passing the hat to help with costs.

aerohead · 10-04-2014, 04:18 PM

Here are some mental ramblings considering wind tunnel data:
*GM reports Cd 0.28 for Chevy VOLT
*A2 wind tunnel reports Cd 0.28 for Chevy VOLT
*GM and A2 appear to come up with same Cd for same car.
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*Toyota reported Cd 0.25 for Prius III
*A2 reported Cd 0.26 for Prius III
*GM might be expected to report Cd 0.26 for Prius III
*Darko reported Cd 0.285 for Prius III
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*If Darko reported Cd 0.268 for Spirit of Ecomodder.com
*A2 and GM might have reported Cd 0.244
*Toyota might have reported Cd 0.235
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*Darko reported Cd 0.251 for folded mirrors
*GM and A2 might have reported Cd 0.228 with folded-mirrors
*Toyota might have reported Cd 0.220 with folded-mirrors
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*Darko reported an estimated Cd 0.24 for a mirror-delete
*GM/A2 might have reported Cd 0.219
*Toyota might have reported Cd 0.210
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*Toyota originally published Cd 0.44 for the T-100
*Darko might have reported Cd 0.501
*If so,this would indicate a 46.5% drag reduction.
*At 65-mph,this might equate to a 25.5% mpg increase(GM Labs,1963)
*or,31.393 mpg if the baseline was around 25-mpg 'naked.'
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*Since the average 65-mph trip results were 34.182 mpg (under poor conditions)
*and if the 25.5% allowance is valid
*Then the mpg difference might be attributed to:
> lower rolling resistance of the H-rated Hankook front tires
> and LRR Bridgestone rear tires
> and 'overdrive,rubber-gearing' of the oversize rear tires.
*Don't know.And I don't know how to find out.
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*As we learn of additional vehicles, wind tunnel-tested,we'll hopefully,see some additional 'overlap' in cars tested,with similar vehicles at different tunnels serving as 'calibration' models,as with the Prius III.
*One door closes and three new ones open!

10-04-2014, 04:18 PM	#128 (permalink)
aerohead Master EcoModder Join Date: Jan 2008 Location: Sanger,Texas,U.S.A. Posts: 16,272 Thanks: 24,394 Thanked 7,363 Times in 4,763 Posts	Thoughts on numbers Here are some mental ramblings considering wind tunnel data: GM reports Cd 0.28 for Chevy VOLT A2 wind tunnel reports Cd 0.28 for Chevy VOLT GM and A2 appear to come up with same Cd for same car. -------------------------------------------------------------------------- Toyota reported Cd 0.25 for Prius III A2 reported Cd 0.26 for Prius III GM might be expected to report Cd 0.26 for Prius III Darko reported Cd 0.285 for Prius III -------------------------------------------------------------------------- If Darko reported Cd 0.268 for Spirit of Ecomodder.com A2 and GM might have reported Cd 0.244 Toyota might have reported Cd 0.235 -------------------------------------------------------------------------- Darko reported Cd 0.251 for folded mirrors GM and A2 might have reported Cd 0.228 with folded-mirrors Toyota might have reported Cd 0.220 with folded-mirrors ------------------------------------------------------------------------- Darko reported an estimated Cd 0.24 for a mirror-delete GM/A2 might have reported Cd 0.219 Toyota might have reported Cd 0.210 ------------------------------------------------------------------------- Toyota originally published Cd 0.44 for the T-100 Darko might have reported Cd 0.501 If so,this would indicate a 46.5% drag reduction. At 65-mph,this might equate to a 25.5% mpg increase(GM Labs,1963) or,31.393 mpg if the baseline was around 25-mpg 'naked.' ------------------------------------------------------------------------- Since the average 65-mph trip results were 34.182 mpg (under poor conditions) and if the 25.5% allowance is valid Then the mpg difference might be attributed to: > lower rolling resistance of the H-rated Hankook front tires > and LRR Bridgestone rear tires > and 'overdrive,rubber-gearing' of the oversize rear tires. Don't know.And I don't know how to find out. ------------------------------------------------------------------------ As we learn of additional vehicles, wind tunnel-tested,we'll hopefully,see some additional 'overlap' in cars tested,with similar vehicles at different tunnels serving as 'calibration' models,as with the Prius III. *One door closes and three new ones open! __________________ Photobucket album: http://s1271.photobucket.com/albums/jj622/aerohead2/