If I'm correct in how I read that then different valve curtain areas would need a different lobe designs to create the vacuum necessary to maintain vacuum profile to suit the fuel being used in relation to piston speed and cylinder fill time.
I take it that low loads means Isothermal Compression and high loads are Adiabatic so how would you have to balance out those demands with intake closing and rpm ranges.
I remember Bruce saying this about it:
The time spent in isothermal compression is critical to the vaporization level of the chamber. When you close the intake valve earlier you increase the time of isothermal compression, thus the engine gains low down power, however the trade off is as you rev it faster the valve closing goes straight into adiabatic and the vaporization suffers and the engine looses power. What ever the temperature of the air in the chamber at the point where it crosses to adiabatic will be the temperature until it drops back out of adiabatic somewhere as the piston slows in the top half of the stroke.
So now can anyone see why I say what I keep saying?
Hint, if you decrease droplet size you will increase vaporization at all points especially in the zones where its inhibited by the type of compression
That’s what carby sizing does too. The whole intake system is a vital part of the vaporization.