I was kinda thinking about it the other day, but say you set the fuel pressure at 40-45 psi, when you boost does the fuel pressure increase? If so, by how much? I know this is basically on what fuel pump, but say a average good one. Rp high flow for a start.

 

On a turbo car, the fuel pressure will increase one psi for every psi of boost (unless you are using an aftermarket rising rate regulator). The pump has nothing to do with the fuel pressure. The differences between fuel pumps is how much fuel the pump can flow at those higher pressures. Smaller flowing pumps will not be able to flow enough fuel at high pressures.