Fuel Pressure Graph & WOT Pressure Drop

MotorvateDIY

I just wanted to share some data on VHR fuel pressure.
Below is a graph from my 2011 G37 Sport Sedan, showing speed (KPH), engine RPM and fuel pressure during a 2nd and 3rd gear WOT run. Outside temp was 20C / 68F.

Fuel pressure is measured by a 100 psi, Honeywell PX3 sensor and is connected to a CJM fuel tap. Data logging is done with my Bluetooth + CAN bus LCD gauges / mini dash. Only mods are Stillen cat-back and K&N drop ins.

Typical idle fuel pressure is 51-53 psi depending on fuel temp. (colder temps result in slightly higher fuel pressure)

During the 2nd + 3rd gear WOT run, it dropped to 47 psi @ 7421 RPM at the top of second BUT only for 0.574 seconds and again to 47 psi @ 7437 RPM at the top of third.

This was more of a drop than I expected, but since it is only for less than 0.6 seconds it can't harm anything.
PLUS based on other data logs, with a stock tune, the AFR spikes VERY rich (10.2!!) from about 7100 RPM until the throttle bodies start to close at 7300 RPM.

Anyways, just wanted to share my findings.

Attached Images

fuel_pres_drop_401_sm.jpeg (88.1 KB, 54 views)