Online tool: shows aerodynamic drag, rolling resistance, power required & est. MPG

[steffen707]

Can you post up an excel file with the calculations? I would love to play around with comparing different vehicles and weights. I know I can just use the online one, but then i've got like 5 windows open and have to copy and paste the data to my excel file to side by side compare more easily.

Thanks.

[oldbeaver]

Dear Steffen707,

I have the spreadsheet but cannot open it myself. I ´don´t have the proper program.

I think I saved it with Open Office and then I erased the program.

Give me yr email and I will send it to you anyway.

OldBeaver

[steffen707]

email sent in pm

[MetroMPG]

Originally Posted by steffen707

Can you post up an excel file with the calculations?

Post 57 links to another forum with a spreadsheet available for download. I'm not sure if it's the same one oldbeaver used:

http://ecomodder.com/forum/showthrea...tml#post184492

[oldbeaver]

Dear MetroMPG,

I used the tools provided by ecomodder here:

Aerodynamic & rolling resistance, power & MPG calculator - EcoModder.com

Enter to FORUM, then look for GARAGE & TOOLS

Choose TOOLS and there you are...

Luck !

OldBeaver

[steffen707]

Originally Posted by MetroMPG

Post 57 links to another forum with a spreadsheet available for download. I'm not sure if it's the same one oldbeaver used:

http://ecomodder.com/forum/showthrea...tml#post184492

The spreadsheet discussed on post 51 isn't the same as the one on the tools section. It is a whole lot more complex, which isn't BAD, but i was hoping to get the simple version found on the tools section.

[XDotNet]

thank you!

[ERTW]

Fe vs road speed is an inverted bathtub. This spreadsheet is only useful within a small speed range (around 80kph).

[88'rolla]

Hello, Ive been a long time lurker here on this board - a search usually finds the information I'm interested in, so I haven't ever really needed to post.

I am trying to derive a simple (read: very simple - no Crr, Δm, a, etc.) mathematical model for the rate of fuel consumption with regards to air resistance only, assuming constant V and m.
So far I've gotten:

B=(BSFC/ρη)Fd

Where η, efficiency, Fd, drag force, and ρ, energy density, are known.
η=1/(BSFC*ρ) => BSFC=1/(η*ρ)
B=fuel consumption (which I'm ultimately trying to find in gal/100mi).

I figure this would be the correct thread. Am I on the right track? If not, any insight would be great.

Thanks, and nice to finally meet everyone!

[aerohead]

Originally Posted by 88'rolla

Hello, Ive been a long time lurker here on this board - a search usually finds the information I'm interested in, so I haven't ever really needed to post.

I am trying to derive a simple (read: very simple - no Crr, Δm, a, etc.) mathematical model for the rate of fuel consumption with regards to air resistance only, assuming constant V and m.
So far I've gotten:

B=(BSFC/ρη)Fd

Where η, efficiency, Fd, drag force, and ρ, energy density, are known.
η=1/(BSFC*ρ) => BSFC=1/(η*ρ)
B=fuel consumption (which I'm ultimately trying to find in gal/100mi).

I figure this would be the correct thread. Am I on the right track? If not, any insight would be great.

Thanks, and nice to finally meet everyone!

If you have a baseline mpg at a steady 55-mph,or 70-mph,and have made changes which affect only the drag coefficient,then the following relationships developed by General Motors, may be used with a high degree of confidence:
*A 10% drag reduction @ 55-mph will yield a 5% increase in mpg .
*A 10% drag reduction @ 70-mph will yield a 6% increase.
From here.you can convert into any useful unit of measure.
The relationship presumes a constant BSFC,and it has been reported by others that proper gear-matching is necessary to derive the full benefit of the drag reduction,but thermodynamically,the percentages are correct.