S-AFC II Setting, confuse

[kylehlub]

I just bought this car and it has a S-Afc II device. I am starting to learn how to use it but it is still confusing me and I looked in here and else where and did not find the anwer I needed. Here is the current setting.

Lo-Thrtl
1000rpm is -4
1600rpm is -4
3000rpm is -3
4000rpm is -2
4600rpm is -3
5000rpm is -3
5600rpm is -4
5000rpm is -4
6000rpm is -4
6600rpm is -4
7000rpm is -4

Hi-Thrtl
1000rpm is -4
1600rpm is -4
3000rpm is -4
4000rpm is -5
4600rpm is -5
5000rpm is -6
5600rpm is -6
5000rpm is -8
6000rpm is -8
6600rpm is -8
7000rpm is -8

1) What is lo thrtl and high thrtl? Can someone explain it in a way that makes sense?
2) I understand that every car has it's own setting but what does the negative number represent, what's the difference in making them bigger, smaller or positive?
3) If you're getting fuel cut, how do you change the setting to get rid of fuel cut?

 

[CanadianTSi]

You have your throttle points, most people set them around 30 and 80, the low throttle settings are used for 30 and under and the high throttle settings are used for 80 and over, anything in between and the S-AFC averages the 2.

When you go to a lower number (farther into the negative) you are making the car see less air therefore it delivers less fuel, more positive and the car see's more air and delivers more fuel.

Do you have a data logger?

 

[98eclipseRS]

just looked at your mods and besides that you will need a logger for sure, if you don't want to be ripping your hair out you are going to want to buy an afpr so that you are not constantly overrunning the stock fpr with the 255.

 

[kylehlub]

Do you mean 30 and 80 as in the speed the car is going?

Example..
Lo-Thrtl
4000rpm is -2

Hi-Thrtl
4000rpm is -5

So assuming that the speed of the car is at 30mph at 4000rpm, it would be -2 but if the speed is at 60mph at 4000rpm, then it is -3.5, if the speed is 100 at 4000rpm, then it's -5.

I have been getting fuel cut when the rpm reaches 5 in 3rd gear, probably around 50-60 mph (not sure of the speed) but it only happens in hot days like 90 degree. It doesn't happen at night around 70 degree? Does this mean I should make the numbers bigger to get more fuel in around 4-6rpm at both lo and high thrtl?


I don't have a dataloger, in fact, I have no idea what a dataloger is. Just bought the car a couple of weeks ago and still trying to learn everything about it. Once I know more about what the car has, I will look into what it needs.

 

[98eclipseRS]

no as in throttle percentage, or how much the pedal is pushed down compared to full throttle so 30 woul be 30% throttle. Second I really really really suggest that you read up on the safc, IT IS A MUST THAT YOU GET A DATALOGGER IF YOU ARE TRYING TO TUNE YOUR CAR.

 

[CanadianTSi]

I would suggest that you don't change any settings until you fully understand what you are doing.

Read This for starters

 

[kylehlub]

I understand that a datalogger is important. But all that stuff is too confusing for me at this point. I just want take things slow and learn about what I have on my car before adding more things onto the car that I don't understand how it works. I am not trying to tune the car,just trying to understand it.

When you go to a lower number (farther into the negative) you are making the car see less air therefore it delivers less fuel, more positive and the car see's more air and delivers more fuel.

If this is the case than why are the negative numbers bigger around 3-5000rpm for high thrtl..I don't understand why the car is set to give less fuel around that rpm. Won't you need more fuel around that rpm like in the lo thrtl setting to give the car more fuel for power?

 

[CanadianTSi]

The Stock ECU knows that the car needs more fuel when you go WOT therefore you don't really have to compensate as it is doing it for you.

Did you read that link I gave you?

 

[kylehlub]

I did read the link and I read several other links on AFC II as well. Here are the links as prove.

http://www.roadraceengineering.com/newafcsetting.htm

These two links actually makes more sense than the one you gave because it is actually talking about the AFC II and not just the AFC.
http://www.apexi-usa.com/support_installation.asp
http://www.stealth316.com/2-safcii-adjust.htm#j7b1

Now do you believe that I actually read it. I didn't say I understood everything I read though. And yes I don't know much about this stuff so forgive me for asking stupid questions.

The Stock ECU knows that the car needs more fuel when you go WOT therefore you don't really have to compensate as it is doing it for you.

1) If the stock ECU knows then what's the point of having an AFC II?

Here is how I understood it so correct me because I am pretty sure I am wrong. Because the car I have has updgrades, eg. 550 injector, bigger turbo, etc. the air flow is increased so the ECU has a program that tells it to cut fuel when the airflow exceeds a certain amount leading to fuel cut. So what the AFC does is change it before it gets to teh ECU. I thought the reason why the numbers are negative is because it's trying to compensate by decreasing the air flow so it doesn't exceed the amount. But if this is the case then what's the point of getting a bigger turbo and injector if you are having to limit it.

If that doesn't make any sense then I would really appreciate it if someone just tell me why the lo thrtl and high thrtl setting is set the way it is. What is the logic behind having the negative numbers decrease in lo thrtl around 3-5 rpm and increase in high thrtl?

 

[CanadianTSi]

1) If the stock ECU knows then what's the point of having an AFC II?

The stock ECU thinks you have 450cc injectors, it has no way of knowing you have 550's therefore the car would run way rich if you didn't take away some fuel.

As for your settings, every car is different and you need a Datalogger so you can look at your fuel trims and o2 values to make sure that the settings for each rpm range are correct.

 

[CyberEye]

I understand that a datalogger is important. But all that stuff is too confusing for me at this point. I just want take things slow and learn about what I have on my car before adding more things onto the car that I don't understand how it works. I am not trying to tune the car,just trying to understand it.

A data logger is ALOT less confusing then the SAFCII, and once you learn the data logger, it will make the SAFCII alot less confusing to learn.

 

[kylehlub]

Thanks CanadianTSI..finally someone answering my question. All I wanted to know was why the numbers are negative. You guys don't even answer the questions and go into suggesting I get other parts for the car. Man, everyone makes things sound so much more complicated that it really is. If you guys just come out and answer what we are asking, everyone would be able to learn this stuff.

Oh yeah..why are we worrying about running rich? Won't that just make the car go faster?

 

[AWDGreenMachine]

Running too rich will just hurt performance. In other words, too much fuel=saturated cylinders =car runs like poop