Apexi S-AFC2, but what about timing?

[Inprogress]

Now the one thing that keeps confusing me is that if i were to control my a/f's with a SAFC or SAFC2, how would i control my timing?...i was wondering this because a local shop said a lot of people think they can up boost by just adding a safc2 and that they were sorely mistaken because what would control timing then?...im wanting to tune with a safc and up the boost also, what types of problems could i run into? and i would up the boost with a Greddy Profec B Spec 2

i did search a little but couuld someone also go over the good and bad abotu the safc on the wrx, or even the sti to be specific

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[Rickyh]

Oh boy. the safc will not control timing. It only controls fuel. From the types of questions you are asking you would probably be better off with some sort of reflash. To use an safc you will need a wideband 02 sensor and an egt gauge. You are also going to need some sort of separate boost controller to be able to do what you want to. All of these things will probably equal the cost of a utec or xede or other form of em that will have much more capabilites than the safc. I am not knocking the safc, because I use one also, but tuning it can be a bit tricky because the ecu will learn around the changes you make if you don't do it correctly, and the ecu will also advance timing as it sees fit, which is out of your control. Do a search on safc before you decide if you really want to go that route. Not saying it can't be done, but there are better options out there.

[Inprogress]

ive had a safc2 before, i know it doesnt control timing i was just wondering what would then, like if there was something that would work along side the safc2 for the timing aspect, and as for tuning it, the guys that tuned it on my rsx would be tuning it again cause they as well have wideband to use and with all that in mind what should i do ? i mean i already have the greddy profec b spec 2...and what do you mean it has to be done right?...i mean with the safc2 isnt it just fuel at certain rpm increments and your done right?...like i would want my a/fs to be around 12.3-12.5, so after all thats done then im done tuning it...so then how would the car learn around it?

[happasaiyan]

http://forums.nasioc.com/forums/showthread.php?t=610746

cliff notes: ditch the safc before you blow your motor.

...and for what its worth, there are varying opinions on how rich to run our cars, but on your STi, you definately dont want to be running 12.3-12.5 on more than 10psi. so basically, take the fuel curves of your rsx and throw them out the window.

[Rickyh]

sigh... if used properly it won't blow your motor. You have just as much chance of grenading your engine with a utec as an safc. Do a search for blown engine and see how many utec equipped cars have blown engines. Is it the utec's fault? No, it was the user.

Under 5k and 65% throttle(this is from memory, so I could be off a bit), the ecu does its best to keep the a/f near stoich, or 14.7. If you try to make corrections too low in the rpm range or at low throttle, the ecu will just work it's way around them to try to remain near 14.7. This is what people mean when they say it will learn around them. I don't know about the 05's, but on my car I have the low throttle corrections at 0, and start hi throttle corrections at 4400. This gets me a stable a/f of 10.8 at 5k moving to 11.2 at redline. My egt's max out at 810C with no knock at all. Pulls very hard. It can be done, but it isn't optimal. This is on an 02 wrx. If you have the money, get something with a lot more control, but in the end, anything can blow your motor if used improperly.

[happasaiyan]

i agree 100% that its the fault of the user that blows the engine up.

but many "expert" tuners were tuning with the emanage on STis and every one i know of ended up with a blown motor.

the 02 WRX ECU is quite different than the 04/05 STi.

if you are manipulating what the ECU sees, as far as MAF (to get more or less fuel), the ECU will then put it in a different load site with different timing values. if you are really pushing 4.5V MAF, where the stock ECU would run 20* timing, but are then telling the ECU that its really only "seeing" 3.8V MAF, which would then put the ECU in a load site where its saying it should be running 26* timing, something is going to get broken really soon.

[TurboRex]

The safc works fine with the sti. I have been doing it for some time now. I even have the perrin injectors. However, you need delta dash to lower your timing and you need an egt gauge or wbo2 to set a/f (I have both).

My advice, however, is to not get the safc. I don't think it offers much hp, maybe 10 at best. The problem is the stock timing is very inconsistent. You would be better off getting a reflash or a utec.

Greg

[2.5rsDOHC]

J&S ultrasafeguard can control timing but im not sure if this is what you want...
http://www.jandssafeguard.com/safeguard.html

[S.V.133]

My friend is a head mechanic for Subaru. There is no need to adjust timing to burn more fuel w/ a refalsh or other tuning methods. Im running a SAFC II & AVC-R. It took a while to get everything tuned properly. Though the car runs GREAT now! I also can monitor everything in the car.

SQC #133
Subaru Queens Crew
www.sqc-ny.com

[happasaiyan]

haha...

[dsmperformance]

Originally Posted by S.V.133

There is no need to adjust timing to burn more fuel w/ a refalsh or other tuning methods.

That is so wrong! Good luck with your set-up though...

[x99percent]

Be aware that playing with an S-AFC type device *CAN* affect your ignition timing!

When you make adjustments to the S-AFC on a WRX, you're tweaking the MAF signal.. yes, the ECU uses the MAF signal to calculate fuel delivery, but what do you think it uses to calculate ignition timing as well?

Example: You attempt to use to S-AFC to run leaner. The stock ECU sees a lower MAF signal (less load), so it calls for less fuel... but it ALSO runs more timing!

UTEC users with large injectors should be familiar with this kind of behavior.

[happasaiyan]

Originally Posted by x99percent

Be aware that playing with an S-AFC type device *CAN* affect your ignition timing!

When you make adjustments to the S-AFC on a WRX, you're tweaking the MAF signal.. yes, the ECU uses the MAF signal to calculate fuel delivery, but what do you think it uses to calculate ignition timing as well?

Example: You attempt to use to S-AFC to run leaner. The stock ECU sees a lower MAF signal (less load), so it calls for less fuel... but it ALSO runs more timing!

UTEC users with large injectors should be familiar with this kind of behavior.

same thing i wrote above...

Originally Posted by happasaiyan

if you are manipulating what the ECU sees, as far as MAF (to get more or less fuel), the ECU will then put it in a different load site with different timing values. if you are really pushing 4.5V MAF, where the stock ECU would run 20* timing, but are then telling the ECU that its really only "seeing" 3.8V MAF, which would then put the ECU in a load site where its saying it should be running 26* timing, something is going to get broken really soon.

but the beauty of using a UTEC is you say what timing you want to run...and the UTEC doesnt do MAF manipulation if you are using OLF. the UTEC itself controls the injectors and fires the coils.