pdq,

What type of cam is on your bow? Typically solo and hatchet type twin cams run around 1.45 or so for an SE/PDF ratio, but this depends also on ATA of the bow in some degree. See if you can find any test reports in Bowhunting World magazine

A bow with lower virtual mass is more efficient. Norb Mullaney uses the virtual mass concept as a way to roll-up all of the inefficiencies in a bow.

The basic idea of virtual mass is if the bow were 100% efficient you could take the KE= 1/2mv^2 equation and solve for velocity directly. What Norb does is say what mass would I have to add to the arrow to make this true. He does this by taking several data points and averaging the result.

At this point you can take the Stored Energy(SE) and plug into the KE equation;

velocity = square root(2 * SE/ mass arrow + virtual mass)