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aerohead · 05-19-2010, 05:54 PM

A back door for us is the relationship between mpg and Cd and it is based in scientific investigation and was reported in 1963 in a SAE paper.
For any vehicle,with an established mpg baseline,determined during constant speed evaluation,a 10% change to Cd will yield
5 % change to mpg at 55-mph
6 % change to mpg at 70-mph
8.5 % change to mpg at 80-mpg ( my value,reverse-engineered from data presented by Chrysler,1941 )
The first two values were verified as still valid as of 1991,in a telephone conversation with General Motors Aerodynamics Laboratory.
There is no reason why we cannot use these relationships.

05-19-2010, 05:54 PM	#8 (permalink)
aerohead Master EcoModder Join Date: Jan 2008 Location: Sanger,Texas,U.S.A. Posts: 16,312 Thanks: 24,439 Thanked 7,386 Times in 4,783 Posts	Delta-mpg=Delta-Cd A back door for us is the relationship between mpg and Cd and it is based in scientific investigation and was reported in 1963 in a SAE paper. For any vehicle,with an established mpg baseline,determined during constant speed evaluation,a 10% change to Cd will yield 5 % change to mpg at 55-mph 6 % change to mpg at 70-mph 8.5 % change to mpg at 80-mpg ( my value,reverse-engineered from data presented by Chrysler,1941 ) The first two values were verified as still valid as of 1991,in a telephone conversation with General Motors Aerodynamics Laboratory. There is no reason why we cannot use these relationships.