Do i need an SAFC2??????

[Svenerachi]

okay. before i buy 200 dollars worth of electronics that i don't need, i need some advice.

i've been advised by a local tuner to purchase an SAFC2 to correct my fuel mapping and such to avoid the dreaded lean BOOM when running nitrous

my question is, what do you guys think. do i need it? i'm only going to be running the 35 and after a while, MAYBE the 55 shot jet.

my complete setup is currently: zex dry nitrous kit, custom 2.25 catback exhaust, agency power lightweight crank pulley, K&N panel filter, and desnorkled intake

i plan on also getting OBX equal length headers in the future... not sure if i'll be doing anything after that except saving up for a new engine :-)


so, again. do i need an SAFC2, will it be effective, and most importantly, is it worth the 200 dollar investment?

thanks guys, your help is greatly appreciated

[Huffer]

If your local tuner has good experience with nitrous'd normally aspirated engines, then I would follow his advice. Maybe see if they'll put you in contact with local owners that are running similar setups.

[Svenerachi]

thats the problem, he's an STi and WRX tuner, he doesn't have any experience with what i'm doing, but he's the best source of information i've been able to find aside from the collective genius here, ofcourse

yeah thats me kissing ass, so come on people, save me 200 bucks or an engine, i'm good with either one, i just want more info


my main reason for asking about the SAFC is that i've heard that the ECU learns around the SAFC, but i've also heard that periodic ECU restarts will solve this problem.

<shrug> like i said, i'm just looking for as much info as i can before i buy something that is expensive on my budget. i'd rather put that money towards headers

[Huffer]

The late 90s ECU's do learn around the SAFC's... this is confirmed in the Impreza ECU, but I haven't heard much about the Legacy ones.

[backpack09]

My only advice is to dump the dry kit. I have never liked nitrous setups that don't dump in the needed fuel when you need it.

Wet kits may be a bit more expensive, but they are a hell of a lot safer for your engine.

[Wiscon_Mark]

You'll want to upgrade injectors so you can actually deliver the fuel needed as well. And yes, the ECU only has certain tolerances that it can work with as far as air flow goes, so you would probably want to get that EM. If you're really serious about keeping a reliable car and putting some n2o into the mix, you can't cheap out.

[Svenerachi]

definately not trying to cheap out, just trying to keep from buying things i don't need

i've checked on converting it to a wet system, but its going to cost me 400 dollars for the zex conversion brain.

i read somewhere about hooking up a 5th injector for other applications (turbo) and was wondering if this might work for me...

i've been told by a subaru tech that the injectors are more than capable of dealing with up to a 75 shot of nitrous safely, but reccomended me upgrading the fuel pump


Do you guys know of anyone or anywhere that is able to reflash the 99LGT ecu???
I'm still kinda at a loss as to what to do for EM

[Wiscon_Mark]

Ask that Subaru tech to reflash it.

[Sarra]

What shot are you running?

A wet kit would have the 5th injector... Though, turbo setups typically just use higher flowing injectors instead of adding a fifth. Upgrading the fuel pump won't help, it might throw the ECU off for a bit until the ECU learns about it properly.

Unless you pulled your dry kit and sold it, or hooked up a piggyback ECU, I don't really know what you can do. I don't think an ECU reflash would help either.

[Wiscon_Mark]

How would the fuel pump throw the ECU off?

[backpack09]

A larger fuel pump will overrun your stock fuel pressure regulator, increasing your fuel pressure at the fuel rail. This will cause the injector to put in more fuel than stock with each pulse. The computer will try its best to adjust injector dead time and pulse length to account for the increase. If your pressure is a lot over stock, your computer will not be able to adjust enough, you will run pig rich, and may inherit other driveability issues.

[Huffer]

Hence the need for an adjustable FPR and proper EM.
And probably a split fuel rail.

[rougeben83]

It depends on what fuel pump you'll be running. If it isn't too much higher than stock, it won't make a lick of difference. If you're running something like a 255lph walbro though...yeah you may get that.

But a fuel pump is only worth it when you've addressed the other choke points in the fuel system; injectors, and regulator.

You may want to think about an RRFR like what some RS-T guys are using to partially address the fuel issue.