I read an interesting article the other day about what BMW did with one of their automotive engines.
Cooling the air going into the combustion chamber is beneficial with any internal combustion engine.
This is one of the reasons why we are so strong on recommending External Breather Systems (EBS), it is also why there is a huge market for cold air intakes. BMW has taken cooling the Intake Air Temperature (IAT) a step further...and given some #'s to show how effective it is.
Those of you with a Power Vision may find it interesting to monitor your IAT with the gauge cluster of your PV. It might surprise you how hot it is.
I don't think any of us will be copying BMW on our Harley's, but the type of Air Cleaner, and whether one uses and EBS can have a significant impact on IAT, which in turn will improve power & economy.
Kevin