[aerohead]

Some points to ponder:
* Axle lube viscosity can vary 95% during 'warmup'
* Axle mechanical efficiency can vary 14% during 'warmup'
* Axle-related power absorption can vary by 0.8- kW during 'warmup'
* Low-temperature testing in the past has revealed 8-mpg @ 4-miles range
.................................................. ..................... 11-mpg @ 15-miles range
.................................................. ..................... 13-mpg @ 30-miles range
* An 18-mph headwind has shown a 16.4% mpg penalty @ 50-mph
* An 18-mph crosswind has shown a 2.15% mpg penalty @ 50-mph
* A 10-degree-yaw crosswind increases drag by Cd 0.055
* A 12-degree-yaw crosswind lowered the Cd of the Arrivett Brother's NHRA Top Fuel Streamliner dragster, from 0.20, to 0.18
* An 18-mph tailwind has shown a 19.42% mpg improvement @ 50-mph
* An 18-mph quartering wind is an unknown quantity
* Pumping losses are higher @ light load
* Pumping losses vary as the square of engine rpm
* 45- minutes @ 55-mph warmup has demonstrated data 'repeatability' for the USEPA
* 'Cold' tires, @ ambient temperature demonstrate 40% higher rolling-resistance than when fully-warmed
* Electronic engine management relies upon ALL 'normal', real-time sensor signal participation in order for the ECU to perform minute, asynchronous EFI and ESA optimization commands, otherwise, A/F ratio and Spark advance will experience excursions, even precipitating loss of 'closed-loop' function, allowing the engine BSFC map to fall to a less efficient island of operation, sacrificing optimum performance.
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* Any 'assumption' of steady-state performance is extremely dubious.
* Without baseline testing, which happens to capture performance spectra at any 'new' velocity experienced during the course of testing after aerodynamic modifications are accomplished, any success in parsing out the actual contribution of a specific aerodynamic modification could be lost in the signal-to-noise of the uncontrolled engine, and performance variability of an 'un-warmed' test vehicle; easily exceeding any 'signal' from the aerodynamics.
Simply allowing engine speed to increase from 2,400-rpm, to 2,450-rpm introduces a 4.2% increase in pumping losses.