View Single Post
Old 05-30-2015, 10:51 AM   #20 (permalink)
BabyDiesel
Lean Burn Cruiser!
 
BabyDiesel's Avatar
 
Join Date: Dec 2012
Location: Johnston County, NC
Posts: 936

Big Blazin' - '88 Chevrolet K5 Blazer Silverado
SUV
90 day: 14.97 mpg (US)

Chili - '00 Honda Insight
Gen-1 Insights
Team Honda
House of Tudor
Team Streamliner
90 day: 72.29 mpg (US)
Thanks: 840
Thanked 491 Times in 310 Posts
Quote:
Originally Posted by Cd View Post
I'm not good at understanding math and such. I'm much more visual.
Even something as simple as your charts makes no sense to me.... but i wish i understood.
One thing i would like to know is if you started the test by adding in the factory quoted Cd figure.
If so, how do people know what variable to use when they don't know their cars original Cd ?
It would be interesting to see if a test would show the car as having the factory quoted Cd if you removed all your mods and retested.
I'm sorry that you are having a difficult time understanding the data, Cd. Is there anything I can do to help? I know you are not the only one who is having difficulty, you're just the only vocal one. I don't have an Education degree for nothing

I input my original Cd figure of 0.33 into the input location and it was waaayyy off. So I started going down: 0.3, 0.29, 0.28 and so on. I would watch the Sum of Errors^2. This showed the total deviation of the pink line in comparison to my data points, squared. When this was minimized as far as I could get it (0.005 something!), then I knew I was pretty spot on

I can used my points that were plotted from my coast-down test and input the old Cd number back in to show the difference. The pink line would show the 0.33 Cd deceleration compared to the 0.269 Cd plot points of now.
__________________



Remember, thank a fellow EM'er for a helpful post!!!
I hypermile better in my cowboy boots

Past threads:
ZX2 modding thread
Ecomodder's Top 10: How they do it!
ZX2 Aerodynamics: Shooting for 0.15 Cd
ZX2 coast-down testing for Cd & Crr

Last edited by BabyDiesel; 05-30-2015 at 10:56 AM..
  Reply With Quote