Post by
Ken@PTUNING »
https://forums.nicoclub.com/ken-ptuning-u259763.html
Wed Jan 13, 2016 6:55 pm
The base fuel pressure should be 36psi (2.5bar) done with the vacuum line disconnected on a stock CA18 fuel system. Connecting the vacuum line will bring it down, likely close to 28psi at idle (depends on how much vacuum the engine pulls). With a standalone, you can set the fuel pressure to whatever you want. I tend to stick to either 3bar (43.5psi, stock for the SR20) or 4bar (58psi) depending on the car. Likely, you'll have good results at 3bar (typical on most Japanese cars). It's high enough for good fuel atomization but not too high to lower fuel pump flow (fuel pump flow capability decreases with fuel pressure). Once your fuel pressure is set, scale your injectors accordingly (example, nominal 550cc injector that gets rated at 543cc @ 43psi or 627 @ 58psi on a manufacturer's spec sheet). If you need more fuel (less duty cycle), you could also up the fuel pressure to compensate.