View Single Post
Old 04-27-2012, 02:46 PM   #6 (permalink)
3-Wheeler
Master EcoModder
 
3-Wheeler's Avatar
 
Join Date: Dec 2008
Location: Southern WI
Posts: 829

AlienMobile - '00 Honda Insight
Team Honda
90 day: 80.05 mpg (US)
Thanks: 101
Thanked 563 Times in 191 Posts
Quote:
Originally Posted by Sven7 View Post
MPG % increase is half of aero % increase.
And it's nice to explain in more detail why this is....

I have done numerous coast down tests with the Insight and Crr and Cd are about equal at 35 mph or so.

This means if you change the aero of your car and make it 100% more slippery to the wind, it will gain you 50% more gas savings, because while the aero part improved 100%, the Crr part stayed the same. Then when you add the new Cd and the old Crr, you have a 50% net gain.

Jim.
  Reply With Quote