Towards the end of completing my greddy turbo using infinity, ID1300x, Walbro 450, SOS 3BAR MAP sensor, and planning on e85. Do I absolutely need a fuel pressure sensor to get the most out of the turbo? The greddy instructions don't state anything about a fuel pressure sensor other than relocating the MAP sensor. Is stock fuel pressure enough to be effective on my fuel setup?

 

Its great sensor to have, especially using E85, to know when your fuel pump is giving up.

 

The aem infinity will adjust, on the fly, for changing fuel pressures(if you have the sensor installed and wired up) in calculating your volumetric effiency to hit a targeted air to fuel ratio. Absolutely get the aem electronic fuel pressure sensor! Having said that your oem fuel pressure will definitely suffice for greddy kit even on e85 thats what i ran for years. The fuel pressure sensor will help aem infinity dial in your fuel that much quicker/better if you feed it this information. At your stage id spend the money on a fuel pressure sensor instead of aftermarket fuel pressure regulator(again the infinity will adjust for fuel pressure issues by raising injector duty cycle)