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Old 01-13-2021, 04:23 PM   #7 (permalink)
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Originally Posted by JulianEdgar View Post
So you actually have no points to your argument except "the technique fails to quantify the known unknowns".

1. What are the known unknowns that invalidate the test procedure?

2. How do these match with the actual results achieved when a known drag change is made?

3. How have you found the approach in actual use - or are you just theorising again?
Powertrain efficiency and BSFC are variable. BSFC dominates the scenario.
'The 'influence coefficient' is a sensitivity factor that relates a percentage change in independent variable to its corresponding percentage change dependent variable.'
'Changes in other vehicle factors may occur as a consequence of drag change, and these must be identified and considered.'
'A drag change causes the locus of the engine's operating points during the test to fall in a different region of the engine's performance map. This can alter the BSFC.'
' aerodynamic influence factor can easily deteriorate to only 60% of its potential value.'
Any load reduction
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