5S-FE Stock FPR, Correct me if I'm wrong but... Options

[Syaoran]

... our stock unit is already a Rising Rate FPR, with a static base pressure of 43.5psi correct?

[Smaay]

you bring up a good question. i never monitored the stock fuel pressure. lets look at this from an aftermarket perspective. yes you feed a vacuum line to the FPR. that tells me that when you are idling and there is vacuum in the manifold. it actually lowers the fuel pressure, but then as you throttle up the pressure rises.

That being said, lets say you add some boost to the system, will the stock FPR continue to raise the fuel pressure like an aftermarket one? and what is the rate that it does raise the pressure. 1:1? multiplier? I just dont know.

the stock FPR in the 3S-GTE looks very similar to the one in the 5S-FE and i believe it is a 1:1 rising rate. Im going to guess that the 5S-FE regulator is a rising type but is limited to what it can do. Meaning once it reached a certain pressure, it wont raise it any more.