determining ball park parasitic loads is not too hard with instrumentation
I just pulled the serpentine and watched the scan gauge
(I really love that thing)
~.1 GPH difference without any belt (from 900-3000 RPM pretty flat)
~.1 GPH difference A/C on and off (idle)
~.12 GPH difference steering wheel still to loaded against the stops (idle)
~.01 GPH difference head lights on and off (maybe)
I think the power steering pump should watch it's back
it is not worth .12 gph to me
for the hyper-miler with manual everything & EOC this may be insignificant
for my truck (and probably the average vehicle) this is significant
during the test my unloaded consumption was ~.46 GPH
parasitic load can be 70% of my idle load and 10-20% of my cruise load
a parasitic input might help folks determine what their "conveniences" cost
just a thought