Thread: Proper way to set up Decel Air on SAFC Neo?

Can you guys please explain to me the proper way to set up the decel air feature on an safc? I think the car is dumping too much fuel which is causing it to stall out when coming to a stop.

The maf is draw thru and the bov is vented.

The directions in the manual blow balls

I found this write up that helped me and I thought I would share.
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Start when the car is cold. (after an overnight rest)

Turn key on, go to decel air settings.

Set throttle to 1%.

Set NE1 to about 4.

Set NE2 to about 5.

Start car.

Adjust NE1 until you get a smooth idle while the engine is still cold. Now start turning it down as low as possible while still maintaining a good idle.

If the car starts sputtering and getting rough, you just went too low. Turn it back up very slowly until it smooths out. You want to leave NE1 on the lowest possible point with a good idle.

Now set NE2 to be about 1 higher than NE1.

This formula shoudl eliminate any stalling or popping from the BOV being open.



Theory: Throttle setting tells the SAFC whenever the pedal is depressed less than 1%, the SAFC should control fuel and ignore everything else (including the MAF)

NE1 is the first RPM point you have selected in your NE Point settings. I put mine at 1000 rpm. I set NE2 at 3000, then NE3 at 4000, and so on in 1000 increments. Setting NE1 down at 1000 gives you the ability to control fuel at idle really well. Besides, you probably don't need to adjust anything between 1000 and 3000. (turbo spools after that, right?)

Setting the air flow percentage at NE1 is basically telling the SAFC a number to use whenever it reaches that RPM and less than the throttle setting. So, as the throttle is let off, the SAFC looks at the NE1 and NE2 points. As RPM rolls back, there is going to be a reduction in air into the engine, yet the MAF has already seen it. The stock ECU is attempting to send the fuel for that air that is now missing... hence your stalling and backfiring. The SAFC catches that signal, ignores it, then tells the ECU exactly how much air flow you have according to your DEC AIR settings at those RPM points. Get it?

RPM comes down, hits NE2, SAFC sees 10%. It tells the ECU it needs 5%. (because you picked that number.) Now the RPM won't dive so hard like it was. It reaches NE1, SAFC sees 6%, you told it 4% and it tells the computer only 4%. The idle sets steadily down to where its supposed to and everybody is happy.

The SAFC is all about tricking the ECU into doing what you want it to.

Your problem is the MAF setup. If you're going to run a draw through MAF setup, you absolutely must recirculate your blowoff valve. If you don't, you're just letting metered air blow out to the atmosphere while all the fuel is just being pumped into your engine.

The ECU reads the MAF to measure the amount of air coming into the engine. So, once the air passes through the MAF the ECU has already compensated for that air by providing the corresponding amount of fuel for the air. If you vent that air to the atmosphere you are giving your engine a bunch of fuel for air that is not there.

When you recirculate the air, it bypasses the MAF so the turbo still pushes the air through the system without pulling air through the MAF sensor. By doing this the ECU doesn't read a bunch of air inturn dumping fuel for air that isn't actually entering the engine. That's why you need to recirculate when you run draw through.

Now, if you really want to dump to atmosphere, you need to reconfigure your MAF setup and run blow through. You run your MAF in the stock location and run your BOV at least 8" before that. You can really place the BOV anywhere in the piping system between the turbo and MAF. DO THIS FIRST BEFORE YOU MESS WITH THE TUNE, OTHERWISE RECIRCULATE YOUR BOV. It is very important that you do this.

I went through the same problem. I reconfigured my setup when I installed my FMIC and haven't had any problems. I just need to fix my idle cuz I screwed with that trying to fix the problem you're now having.

Hope this helps.

Lance

Thanks for the help guys. The maf was moved to a blow thru setup and the car is definitely pulling better and idling better but I did notice that when the engine is warm it will stall out when starting unless we give it gas.

After speaking to someone who worked on a lot of sr20de-t setups, he said something about back pressure or lack of due to the turbo that causes that and there is no way to correct that problem. When the engine is cold it starts right up and idles without having to give it any gas.

No problem, man.