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Old 06-14-2018, 02:24 PM   #97 (permalink)
Easter McoModder
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Join Date: Mar 2010
Location: West Texas, US
Posts: 363

'99 Subaru OLL 2.5L - '99 Subaru Outback Legacy Limited
90 day: 22.57 mpg (US)

Rabbit - '08 VW Rabbit S
90 day: 32.93 mpg (US)
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Originally Posted by MetroMPG View Post
Aerodynamic & rolling resistance calculator -

Back in the day, krousdb made a spreadsheet to calculate aero & rolling resistance forces against his del Sol, their respective power requirements, and effect on fuel consumption at various speeds.

I've ported/expanded the spreadsheet into an online tool which asks you to enter or accept default values for...
- vehicle weight
- Crr (coefficient of rolling resistance - .008 represents a low rolling resistance tire on a smooth surface - see Wikipedia for other sample values)
- Cd
- Frontal Area
- Fuel energy density (in Watt hours / US gallon)
- Engine efficiency
- Air density (rho)
... and it spits out a table showing resistance force values, estimated power requirements and fuel consumption across a range of speeds.

It's online at EM here: Aerodynamic & rolling resistance calculator -

It's not perfect (e.g. engine efficiency changes with load in real life, but remains fixed at the value you supply for all speeds in the calculations for fuel consumption).

Discussion, questions, suggestions welcome.
Is there some kind of a database that offers this information for all make and models? Thanks!
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