Quote:
Originally Posted by MGB=MPG
its better than it was.
is that a linear calculation/formula ?
whats the figures for a .4 and the next goal a .25
my car looks slick and is only rated at .4 ; .3 +/- seems to be current industry standard ..
approach to theoretical perfection is asymptotic . effort to achieve each incremental gain increases at an increasing rate ,,
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MGB,it turns out the the difference is simply a percentage difference between wherever you 'are' and where you'd think of going,so its just an arithmetic change.
If you're at Cd 0.40 and you streamline down to Cd 0.25,then,
0.4/0.25 = 0.625,or,only 62.5% of your original drag remains,a 37.5 % drag reduction.
The horsepower necessary to overcome aero drag to maintain the same velocity would be reduced by 37.5 % also,freeing up some power for hill climbing,passing,etc..
If your engines BSFC map didn't move around do to the change ( a better bet today with EFI engines ) ,given rolling resistance as a constant,you'd pick up around 18.75 % better mpg at this speed.More at higher velocity.