I try to log on windless days, but often there is still  a wind of a few mph.

Apparently even for my small car a 5mph head wind at 70 mph vehicle speed could take about 5HP (which is 4% to 5%) off the reported power.

Any chance of being able to input a head/tail wind speed which would be applied to the vehicle speed before calculating the aero drag.

I know that doing runs in both directions will more or less compensate for this, but the downside is that neither of the two resulting dyno plots is correct.  They will just show a ~10HP difference which needs to be split.

 
Many thanks.


see this calculator:

http://ecomodder.com/forum/tool-aero-rolling-resistance.php