But remember it's not the pressure that matters. It's the molecules of air that matters. Pressure is a function of molecules of air at a temperature in a volume.
PV=nR T
P- pressure; V - volume; n- moles (molecules) gas; R - universal gas constant; T is temperature in K. If the temperature goes down and everything else is constant, the pressure goes down proportionally. Here you also have more volume but it's fairly minimal considering we approximate a steady state condition. Essentially the volume is tied to the rate of consumption of the engine which we assume to be roughly constant on two similar pulls.
This is why I'm dying to know what my turbo is going to do with the smaller hot side housing. There's a balance between choking it off and driving up egt's and making boost more efficiently. I have a feeling, the smaller housing may be better for driving empty and the bigger one might be better for loaded just because the foot will be closer to the floor loaded and it might start to choke with the smaller housing. But I'm also using the Banks up pipe which is t3 so that may choke it a bit too. We shall see I hope.