What is this I don't even....
Do you have a standard ECU in the car? or an aftermarket one?
Need more info, Greddy Plenum? turbo? etc
I cant see how you will lose power with a bigger throttle body...unless you have a standard ecu and it is having a fit.
I bet $50s that you're have a short running forward facing plenum
it is needed to keep the fuel flow linear(ish) to injector opening time, otherwise, say you have 45psi rail pressure and 45psi boost pressure, no fuel will flow out of the injector due to no pressure differential
yeah, I think titan was referring to you have to subtract the amount of pressure in the inlet, so 65psi rail pressure - 18psi boost pressure = 47psi effective rail pressure