Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - Project: Geo Metro boat tail prototype

3-Wheeler · 01-06-2010, 11:09 PM

Hi Guys,

So if Metro had a fuel mileage efficiency gain of 15% with the boat tail, then according to what Aerohead has mentioned...

Metro would also have had a CdA reduction of 15% * 2 = 30%

So if Metro were to do a coast down test, his distance should improve by roughly 30% since he now has that much less aero drag (ignoring Crr for a moment).

Again I can't vouch for what Aerohead is saying, but if true, then above is accurate.

Not to belabor the point, but Metro would certainly want to do his mileage test on an almost calm day to make deciphering the data easier.

Fortunately he measured his fuel consumption going both directions on the road for A..B..A, so any change in air drag (wind speed and resultant fuel consumption) would show up.

Jim.

01-06-2010, 11:09 PM	#413 (permalink)
3-Wheeler Master EcoModder Join Date: Dec 2008 Location: Southern WI Posts: 829 AlienMobile - '00 Honda Insight Team Honda 90 day: 80.05 mpg (US) Thanks: 101 Thanked 560 Times in 191 Posts	Hi Guys, So if Metro had a fuel mileage efficiency gain of 15% with the boat tail, then according to what Aerohead has mentioned... Metro would also have had a CdA reduction of 15% * 2 = 30% So if Metro were to do a coast down test, his distance should improve by roughly 30% since he now has that much less aero drag (ignoring Crr for a moment). Again I can't vouch for what Aerohead is saying, but if true, then above is accurate. Not to belabor the point, but Metro would certainly want to do his mileage test on an almost calm day to make deciphering the data easier. Fortunately he measured his fuel consumption going both directions on the road for A..B..A, so any change in air drag (wind speed and resultant fuel consumption) would show up. Jim.