Did you look at th least picture I posted it has the conditions in the dyno.. They are all right around a 2 degree difference for the dyno.run 2 years ago and last weekend

Perhaps it has to do with some rotational inertia forces as well. I am not a physics expect, so it starts to hurt my brain when getting into the finer details of these matters.

But due to a 4:1 ratio allowing the engines rotational mass and drivetrain mass to accelerate much more quickly, perhaps this is consuming more energy. If this is the case, than it would apply to even when we make pure HP additions... we are used to seeing only the power gained without considering the losses to inertia... where with a gearing change you have not actually gained engine power but by increasing acceleration, inertia losses still climb, and the dyno will highlight the inertial losses when not concealed by (packaged with) additional engine power..

<shrug> sounds good to me?