New injectors or playing with rise/rate

[heavy1metal]

Been talking to a friend of mine. He suggests that I use rise/rate. Using a fuel pressure regulator.

I was just thinking of buying some good old tomei 555cc injectors and just maping the ECU at a dyno shop.

My only delmia, what are some disadvantages of rise/rate?

[Hijacker]

rising fuel pressure is not an effective way to get around buying higher flow injectors. You can get a bit more from the duty cycle, but not enough to justify upping the boost. If anything, all you do is force the injector to leak from being subjected to higher than normal fuel pressure.

in the end, spending the cash on high flow injectors is money well spent.

[heavy1metal]

Yea, with what little understanding i have, i was thinking pretty much the same thing. I really do not want to force 2x the pressure out of my injectors. Thank you for the input.

[95lstegman]

if you just want a little more power you can push the fuel pressure up a bit. the stock SR20DET fuel pressure regulator is a rising rate unit providing 1psi increase in fuel pressure for every 1psi of boost. a lot of the FWD guys raise base fuel pressure from ~45psi stock to 60psi with the Nismo FPR. "the 4 bar fuel mod" or something is what they call it. i'm not sure how much more power that will support, but it will need dyno tuning in any case. i don't think that kind of fuel pressure would be bad for them, as i've seen Honda fuel injectors supporting over 120psi every day for a couple years on those "bolt-on" turbo kits they have for Hondas. they take stock 240cc/min injectors and slam the fuel pressure up 10psi for every psi of boost and many see 135psi fuel pressure. admittedly, these die after a couple years, but 135psi is pretty impressive that they will function at all, let alone actually run pretty well.

i guess my point is that if Hondas' Denso injectors can push over 125psi for a couple years, how come Nissan injectors couldn't hold 75psi (60psi base + 15psi of boost) forever?