View Single Post
Old 11-04-2010, 02:53 PM   #266 (permalink)
Master EcoModder
3-Wheeler's Avatar
Join Date: Dec 2008
Location: Southern WI
Posts: 827

AlienMobile - '00 Honda Insight
Team Honda
90 day: 80.05 mpg (US)
Thanks: 101
Thanked 558 Times in 191 Posts
Originally Posted by 3-Wheeler View Post
Hi Darin,

....Besides the ongoing coast down tests, I have two tanks of gas that say the increase in efficiency due to the tail is small for the Insight. Of course we can always take this with a grain of salt, as the ambient conditions are not the same now as they were last spring, when I stopped driving the car, but check the figures during the same months last year, and there is a slight increase, but not 10%.....
Whoops, the above statement while being true is a little misleading... Let me explain....

I typically drive on old crusty backroads to work, and my "high" average speed is about 45 mph or less.

At this slow speed, think about how much (or little) the tail will help. Not much because the air load on the car is so low, probably lower than the rolling drag.

And for this reason, the gas mileage figures are not going to show much benefit of the tail, no matter how nicely it is designed.

I felt kind of silly today, after figuring this out. Some higher speed gas usage tests will show more of a difference, just not at the speeds I typically drive.


Last edited by 3-Wheeler; 11-04-2010 at 02:58 PM..
  Reply With Quote