It was long held that "inertia fill", resulting from intake charge velocity after BDC, despite the fact that the piston is going the wrong way, will improve VE.
Vizard believes that this is more rare and less effective than supposed, and has little value compared to the same intake event beginning earlier (advanced).
Blair suggests using "charge mass" (weight of molecules) rather than volume to make the VE, CR and CCP effects more clear.
Indeed, the era of a build and the inherent limitations of components matter. Where cylinder head design and valve size is limiting, velocity stacks and a longer rod ratio can improve VE via inertial fill. Given a better flowing head & larger intake valves an earlier valve event may be in order (but then we need to be concerned with overlap and potential exhaust gas reversion diluting the charge.)
I am not familiar with Blair's work in particular but I have read others who approach the discussion from the perspective of stoichiometry with a concomitant focus on the mass of fuel and air. Is there a specific Blair article you can recommend?
