2bits

Plain and simple....^^^^

silvertibbs

I'm gonna leave the main parts of this up to someone that owns one. But basically it controls your Air/Fuel Ratios to maximize your fuel to get the most power out of it.

2bits

So basicly a mini standalone??

Zman

More than a mini Standaolone, it would be like a part of it. A standalone takes care of almost (if not everything) in your car, fuel delivery, ignition timing, boost, redline limiter and any other thing you need to be controled... electronicaly.
A SAFC only takes car of the fuel delivery, and usually just tricks the ECU so that you can have more/less fuel according to your tunning. The problem is many times the ECU learns how to compensate for the SAFC tricks, and thus you end where you begun. A stand alone is way much better than just a SAFC, but of course if you're not planning on doing extensive mods for your engine, the cost/benefit would not be positive. Let's say the more things you put in your engine, the more power you could squeeze out of them with a standalone.

'treezy

What do you do when the ECU learns tricks to get around the SAFC?
Just reset it every time?
Is there any way to avoid this?

Zman

I'll be honest with you, I'm no expert with these matters, but what I know is it has everuthing to do with your tuning. As your ECU's are closed loop (and I say your because my ECU is open loop) they tend to set everything to emissions perfection, and not performance.
So, if you trick the ECU into putting more fuel and it "realizes" about that through O2 sensors, it will diminish the fuel injection. Random has posted several posts on www.hyundaiaftermarket.com/old try searching there, I'm sure your answer is there I don't know about www.RDTiburon.com/old but there's probably some interesting info there too.

CyberShark

i think the best way to tune it right is with the assistance of a dyno.

UltraTibby

<div class='quotetop'>QUOTE (CyberShark)</div><div class='quotemain'>i think the best way to tune it right is with the assistance of a dyno.</div>

And a tech who knows what he is doing laugh.gif

supry

What the safc does is change the voltage going to the computer from the MAF or MAP, either by raising it or decreasing it depending on what you want to do. The ECU sees this voltage then calculates how much air is going into the engine, then compensates with fuel. Say, when you lean the mixture on the SAFC, the signal going to the ecu says that less air is going into the engine than acutally is, so the ecu sends less fuel, so you will run leaner.

The problem arises when the o2 sensors see that the car is running richer or leaner than it should with the values that the ecu sees, then the ecu will compesate, and like Zman said, you end up where you started. The way around this is o2 simulaters, which send an ocillating voltage between 3 and 5 volts to the ECU, making it think that everything is okay and eliminating your o2 sensors completly. When Tuned with a good dyno and tech though, you can stay within the parameters of the ecu and still gain HP.

The issue with closed loop and open loop with our cars I'm still not clear on. I've been told that our cars run in closed loop (ignoring maf and o2 sensors) under 50% throttle then go to open loop above 50%, but, the last time I wired my safc, I left all the settings at 0, then ran below 50% throttle for 10 miles and my CEL came on because the downstream o2 sensor was reading lean or rich. But once I get the simulator everything should be fine.

Zman

The Closed Loop ECU works in a constant evaluation of what's going on, thus, it reads what exits of the combustion chamber, compares that with it's parameters, and if it's not "what it should be" ECU adjusts fuel injection and timing basically, after doing so it reads the exhaust again and again adjusts if necesary, and it never ends, that's why it's called Closed Loop.

In an Open Loop ECU, the ECU takes initial readings of the situation, such as rpm range, throttle position, acceleration, speed, etc, etc, and adjusts fuel and timing and it just leaves it there, no matter what's coming out through the exhast pipe, the cicle ends there, that's why it's called Open Loop, because it doesn't incorporate the exhaust feedback. In this Type of ECU, it's also monitoring the engine 100% of the time, but it does not adjust conditions to comply with emissions, so in a certain way it's partially a closed loop ecu, but not regarding emissions.