Quote:
Originally Posted by KamperBob
In all science and engineering there is inherent risk of over simplifying something complex like aero down to a scalar number like Cd, especially without any tolerance such as measurement variation or confidence bounds. Reporting Cd = 0.25 +/- 0.1, for example, would be more useful. How many fellow EMers have spanked their EPA rating big time?  |
I couldn't have said it better, and I am an engineer! In addition to the confidence bounds issue, you also have to question the choice of measurement method. GM talks about a "new" method of measuring Cd. I think it is pretty safe to say that they will not have chosen a method which doesn't help separate them from their competition. I'm glad to have found at least one soul who agrees that published Cd numbers might not be as reliable as we have thought
Some of the "old" numbers have been proven wrong with more modern technology. How they got "wrong" we can all speculate, but I have my own personal explanation
