I have been visiting this topic in my head for many years.
If I could run an engine in a hypothetical lab condition eliminating outside influences such as road conditions, terrain, humidity, temperature, wind, drag, etc. With these parameters set, I record fuel economy over a range of engine loads and speeds with oil "x". Now, with oil x completely flushed, I now run oil "y". Oil y shows an average MPG better than oil x.
Would the increase of average MPG of oil y be due to the oils reduction of mechanical friction in the engine or the reduced hydrodynamic drag of the oil? Or would both contribute.
Facts please. No speculation please. References to publications would be extremely helpful.
If I could run an engine in a hypothetical lab condition eliminating outside influences such as road conditions, terrain, humidity, temperature, wind, drag, etc. With these parameters set, I record fuel economy over a range of engine loads and speeds with oil "x". Now, with oil x completely flushed, I now run oil "y". Oil y shows an average MPG better than oil x.
Would the increase of average MPG of oil y be due to the oils reduction of mechanical friction in the engine or the reduced hydrodynamic drag of the oil? Or would both contribute.
Facts please. No speculation please. References to publications would be extremely helpful.