using safc on stock injectors (KA24ET)

[fullmetalx]

i'm trying to find out if anyone has ever experimented with this kind of setup here before. i've gone searching but didn't find anything that answered my question.
here is the setup: stock ka24e, z31 t3 turbo, stock 270cc injectors, and a safc1.
i'm planning on running with very low boost ~5 psi. my question is, is it possible to control the stock injectors to flow more fuel? as in entering +10...+40% on the hi/lo throttle settings on the safc to compensate the needed fuel.
in my own theory, it sounds similar to the additional fuel when an fmu(rising rate regulator) is used or a larger injector but with the decreased adjustment(-10...40% on the safc settings)
am i in the right direction, theory wise? any input would be appreciated. thanks

[GSXRJJordan]

Nope, doesn't change the max they can flow (unless you actually do use a rising rate fuel pressure reg), all you'd be changing is how fast they get to max flow. And remember, injectors don't like to come back to closed when you push them past 80% duty cycle.

Get SR injectors, they're plentiful and cheap. Then run as much boost as you can while still keeping timing in check (with actual engine managment, not a gay ass SAFC), and be happy.

[Neejay]

+1 to what he said^

Out of curiosity, why are you only running stock injectors? I would at LEAST get SR injectors.

[orion::S14]

KA24E has top feeds, so the SR 370's aren't a drop-in option...

And for any other option, YOU MUST BUY A WALBRO PUMP. Or some other high flow fuel pump.

...

Your best bet, if you must...would be to bump the fuel pressure, and then retune based off that.

Higher fuel pressure increases the flow rating across the board...SO:

SQUARE ROOT of {new pressure / stock pressure} TIMES stock injector size.

SO...

SQUARE ROOT of { P / 43.5 } x 270 = ______________

If you bump the fuel pressure (P) to 4bar (58psi)...then you increase flow by 15% or so.

1.154 x 270cc = 312cc

That'll be good for roughly 200rwhp.

"Safe" base fuel pressure is, IMO...limited to ~5bar. You have a 20 year old fuel system, with old lines and clamps. Don;t let one blow off and burn down your car.

- Brian

[Neejay]

Ah, sorry, misread the engine code.

[louisdaboois]

go to the junk yard and score some n/a or gst eclipse injectors. most of the time junk yards are cluttered with them, and they drop in to KAE's

[steve_o1989]

You can use some dsm 450cc's, or some rx-7(forget the years on that one) And I believe that the injectors off of a Ca18det will work if you can track some down. For the amount that it will cost, it is deffinatly worth it in the long run. Some of the above injectors may require resistors (forget which ones right now)

[fullmetalx]

Nope, doesn't change the max they can flow (unless you actually do use a rising rate fuel pressure reg), all you'd be changing is how fast they get to max flow. And remember, injectors don't like to come back to closed when you push them past 80% duty cycle.


thanks gsxrjordan. that just clarified it for me.

[Irukandji]

There are a lot of ghetto ass turbo builds on ka-t.org
I think some sohc guys use FMU's with stock injectors, but it's not recommended. I really don't think 5psi is worth your time. It'll be like +25hp , several hundred dollars down the drain, and an unreliable ghetto tune.
Keep it stock

[e1_griego]

Yeah, pick up a set of high-impedance rx7 injectors (460cc). Drop right in, and you just have to cut a little notch out of the injector plug to get the 240 pigtails to fit right.

Simple simple.

Alex