does anyone have any experience or knowlege with the APEXi SAFC? if so, please share it with the rest of us! im looking into buying one. i hear it's a pretty good bang-for-your-buck, and it looks awesome.

http://www.apexi-usa.com/electronics_safc.asp

 

ask greenbox, he uses it to tune/watch his nitrous setup

 

you wont need it unless they come out with an FI kit soon. what the S-AFC does is take the electrical signal (in my car's case an AC wave developed by a voltage to frequency convertor) and increases or decreases its value where you specify. this way, the ecu sees the altered frequency and applies its injector pulse width accordingly. lets say you want to lean out your mixture at 1000 rpms so you bring the percentage down to -10%. The S-AFC reduces the air signal and the ecu thinks there is less air going into the engine than actually is. Obviously, since the ecu sees less air, it puts in less fuel...effectively leaning out the mixture. The problem is, the only time this will really help you is under what is called "open-loop operation". This is the point when the ecu uses mostly O2 voltage to determince fuel mixture (usually under WOT and most of the time upper half of the rpm band). At all other times, the ecu is closed loop operation where the mixture cycles back and forth between rich and lean. In closed loop, the air signal isnt that important when determining fuel mixture, so the SAFC wont help you there, and in open loop with no forced induction, more agressive timing/camshaft profile, or the need to control larger injectors in any way...the only thing you can do is make the mixture too lean or too rich. If you need to know anything else...lemme know.

 

Preach on DSMer!!

I used to own a 2g =) 50 trim and all =)

I dont think there is any need for a AFC as of right now. You can try to lean out the motor to see if it'll make more power, but gains would be minimal.

 

RedBox, have you sold yours yet?

 

this part is not needed right now for the scion. there is not enough power options out there. 92tsitalon pretty much nailed it.

 

good post 92tsitalon, you are exactly right......

you shouldn't be concerned right now about getting a S-AFC. look more into it when you have some heavy mods on your car.

 

it should be sold, i'm waiting for the money order to get here

 

I'm looking to the future, hence I ask... I've become an advocate of using Nitrous in a setup like this (with proper engine preparation).. but can this unit be programmed for that kind of contingency?