sideways danny wrote:why do you all change the FPR? I'm still running a stock one with 18psi on a GT28RS. I can't see that there's any reason to need a different one except if you need more fuel pressure because the injectors are maxed. if you have bigger injectors than standard anyway you don't need that.
Because here in the US we've got to change out the stock fuel pump. It's only good to maybe 200hp.
Most of us get the Walbro 255lph. That pumps extra flow volume and pressure ability cause it to overrun the stock fuel pressure regulator, which of course makes it run rich. The other problem is that, at least in my case, it wasn't a predictable overrun. My fuel pressures were all over the place and made tuning next to impossible.
Static fuel pressure is supposed to be 36psi. In my particular instance, I was at 48psi. That's a 30% increase in pressure. In the scheme of fuel volume, that's not a tremendous increase (It takes 4 times the pressure to double the volume), but the lack of stability was the problem in my particular case.
I don't know why it would be too much different for others.