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Old 07-20-2013, 05:27 PM   #15 (permalink)
aerohead
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Polar moment of inertia

Quote:
Originally Posted by Honda View Post
Let say we hove 2 identical cars that weigh 3000 LBS, one has light rims and the other has heavy rims with rear seat delete or any other component to make it stay at 3000 LBS.
Will the fuel economy be affected comparing the 2 cars?
In the SAE HANDBOOK (4-volumes) they address your question in the paper dealing with coastdown testing.
They show how the values can be estimated and also the pendulum apparatus they use to actually measure the inertial effects as a contribution to overall dynamic mass.
All rotational mass should be accounted for including engine and gear train.
The SAE material is probably the best 'science' you're apt to find.
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