S-AFC ups and downs

[y2k02scoob]

i am getting an afc and was just wondering how many of u guys have one and how much of an improvement it was. I am getting a pretty good deal on one (150) and figured it wouldn't hurt.

I have txs turboback, gfb pullies, greddy intake, and mbc set at 15 and with these mods and some good driving i was able to muster a 13.25 @101.?? so i am hoping and praying that 12s are capable with an afc. i might be expectin to much but it is still a helpful mod.

I was also if anyone had some maps for it

thanks

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[y2k02scoob]

no one?

[ccnada]

For me the SAFC works good. I really needed it when I upgraded my intake to an APS one. I had to turn up the fuel because the intake was allowing more air past the MAF. This was on stock injectors. Now I have STI ones and I use it to turn down the fuel at WOT. I do use a Greddy Air/Fuel Sensor and Ecutek Delta Dash for further tuning. If you want in the 12's its best to get it tuned on a dyno. Don't forget you must also address timing!

Cedric

[Javier]

What's a good way to address timing with an afc? I know apex'i makes the S-ITC which does timing but I never see it used by anyone. I know that unichips and UTEC can do it also but both make the use of an afc pointless. What other options are there if you have an afc?

[recursian]

The problem is that you don't have enough control. You can't just adjust fuel by RPM and expect it to work right. You will only be able to adjust fuel at wide open throttle. This is insufficient. You must be able to adjust fuel by manifold pressure and RPM. With my wideband, you would see your a/f ratios moving around, sometimes too lean, at part throttle- open loop. You can think of the S-AFC as having only one slice of a useful fuel map. You would need several of the same slices, at multiple load values, to complete the map. The S-AFC gets by only because during close loop operation, the factory computer can trim out incorrect offsets that you may have programmed for full throttle. If you are only interested in wot performance, it will work. However, if you want great drivability as well, it is a severe compromise. You will also be relying on the factory computer's knock detection feedback loop to manage your timing. While it's a capable system, I would rather have my own timing maps to make sure things are on the safe side. In fact, you need an equal amount of timing map slices as you do fuel map slices to have a complete system.

[y2k02scoob]

what to i need to make it work (tuning( or are u just basically saying i shouldn't trust it. because as many of people that use these things i can't see that they are inaccurate and incorporative. and why would i need to adjust timing?

i know that it helps to add a little here or there but if i leave it as is then all i do is eliminate a tuning factor. am i totally wrong here in my line of thinking?

by the way when it comes to tuning i know very little and i did plan on having it tuned by a shop but i don't mind being called an idiot because i know how tuning works and what it does but i can't do it. so any info would be great

like i said i don't pllan to tune it but i want it tuned right and if it cant be done without a dyno or without a wideband than screw it i will just wait and save up for a utec

[recursian]

If you are satisfied with the way your car runs at part throttle, and with the margin of safety you now have, then the s-afc will work good for you. The key is that it basically is good for tuning wide open throttle fuel mixture only. There is no load based tuning option. It does not support timing adjustments either. From what you have said, I would think you would be very happy with it because your goal is good 1/4 mile times (wide open throttle). If you had a wideband a/f ratio kit you would be able to adjust it yourself. At least you could adjust it for safe wot a/f ratios. Without a wideband, you really, really need to take it to a dyno shop.

[mysubaruimp]

the new s-afc II has a knock sensor and is more adjustable(200 RPM increments vs. the old 500 rpm increments

[joeyvaz]

Don't mean to freeload, but I have a question regarding the S-AFC II. At idle, my RPMs seem to be right on the money. When I give the car gas, the RPMs seem to be way off (like 500 RPM or so) Did I do something wrong when I hooked it up, or is it just the settings that need adjusting.

Thanks,
Joe

[rex n effect]

spend that 150 on a catless uppipe.

[TurboRex]

The safc works extremely well for idle, part-throttle, and wot adjustments. You need the ecutek to help with tuning as well as a wideband or egt gauge. On stock injectors you can maybe add about 10hp but the stock ecu can be fickle so it is easy to hurt hp as well if you do not tune carefully.

I think the safc is really not needed unless you go to a larger turbo and larger injectors and/or fuel pump.

Good luck,

Greg

[mysubaruimp]

Originally posted by joeyvaz
Don't mean to freeload, but I have a question regarding the S-AFC II. At idle, my RPMs seem to be right on the money. When I give the car gas, the RPMs seem to be way off (like 500 RPM or so) Did I do something wrong when I hooked it up, or is it just the settings that need adjusting.

Thanks,
Joe

mine is right on the mark all the way through, also matches rev/speed meter rpms perfectly. try to go back into setup(the etc. menu i think) and make sure its at 4cyl, the next thing is like 4sp or 4pt, something like that, make sure it has a 4 in it. then make sure the little arrow is pointing up and to the right. thats all i can think of