Quote:
Originally Posted by AeroMcAeroFace
2-3) I think they will be a linear thing and can be all integrated into "rolling resistance"
4) Mechanical resistance is maybe 5% of the total drag, even if it changes by an extreme 10% it is only 5.5% of total drag and so while not irrelevant it is not a huge difference.
5) BSFC if it does change will be tiny and I believe will be negligible over the few percent increase/decrease in engine speed.
6) Wind, well nothing can change that, but on a calm day I see no problem with multiple bidirectional averaged runs a-b-a-b-a-b as a minimum. So, just don't do it on a particularly windy day, unless you are specifically testing crosswind drag.
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2) engine accessory power absorption would be linear if belt driven
3) rolling resistance would be linear all the way to standing wave, beyond the performance envelope of the vehicle
4) I have 8% powertrain loss for an overdrive, manual transaxle powertrain, like the gen-I Insight. It's not as significant as BSFC, although, rates #2 in Sovran's research.
5) A BSFC map for the specific test vehicle would be welcome. This is the #1 bone of contention in Sovran's SAE Paper. It must be known in order to sort out any actual benefit of an aerodynamic modification, lacking gear-matching
6) Wind is really problematic. Datalogging would be imperative if one were to undertake testing during wind.