would hondas smaller displacment motors beat an HF at the gas milage game just because they are smaller ?

 

possibly if they were also in a smaller car, though the hf has the advantage of being designed specifically for mileage with the egr, 8 valve head and cam and all that...

 

Please place technical questions directly into the thread title whenever possible -- Title edited.

 

I'm not sure about this exact motor, but I know that when BMW designed the motor for the 325e in the eighties, they reduced the number of cam journals, used lower tension springs, and other items to help the engine be more efficient.

Motors are not necessarily more fuel efficient just because they are smaller. Additionally, you must figure in thermal efficiency of the motor too, as you want the heat of the ignition to stay in the combustion gasses and not escape into the cylinder walls and head. One of the key factors to this is the surface area/volume for the cylinder wall (lower is better for efficiency) which goes up as the cylinders get smaller. Also, different materials will lead to different heat transfer rates. Lastly, don't forget about the age and tune of the engine; older engines are likely to have "slop" in them and older engines run different computers (less efficient) than modern engines. Lots of factors here... Ultimately, the lighter the load and the greatest load/rpm (ie, for the same load, a lower rpm will require less fuel) will generally net the greatest efficiency.