I suggest to you to get a Field Extension harness and and HKS AFR. You can get the field harness for $140 shipped from Z1 Performance and you can get an HKS Super AFR (fuel controller) for $225 shipped from several vendors. I
have heard of several people having problems with Apexi SAFC2. They don't pick up RPM signals correctly in some of the units. I heard that alot are coming back for warranty work. Some work fine, but you are taking a small risk. The Super AFR works great. Someone posted there settings from the dyno to give 12.0 to 11.5 A/F ratios. You can use those settings. Just search for the post of HKS and AFR, you will find it.


Brian

 

That is great to know. Thank you for your info. One question though, how does a preset setting going to deal with the boost control, intake, and catback I have added to the EVO? I assume, from my lack of knowledge, the setting was designed to optimize the stock set up? Thank you for your response.

 

Thanks my friend. It sounds like you have a little experince in the matter. I have seen this A/F ratio before in some other post. Are the numbers you have posted the optimal ratios for this car or any car? I would assume that the dyno comes into play when the O2 dyno sensor tells you to program your A/F controll .

You lost me on .92 and .94 mvolts. I would welcome an explanation on the ratios and mvolts. Thanks

 

On DSM's people used to tune with O2 voltage readings. This was before Wideband O2 sensors were widely available and affordable. An OEM narrow band O2 sensor will read between 0 millivolts to 1000 millivolts (or 1 volt). At 1 volt the airfuel ratio is PIG rich. The OEM O2 sensor wont read any richer than that. It was commonly accepted with people to run .87 millivolts with high octane race gas. When running 93 octane, you should run a little bit richer than that. .90 to .92 is about as lean as you want to run, to be safe. The O2 sensors output will change slightly with heat, that is why you can not tune to the ragged edge with this method, but you can do better than the factory settings.

My Apexi Turbo timer ties into the factory O2 sensor and reads O2 voltage and a theoretical Air/Fuel ratio. When you go WOT it will run off the scale rich on the voltage reading. You can get it down to .92 to .94 mV with an Air fuel controller.

BTW, did you have any trouble getting the flange to seal on your Catback and the muffler assembly connection? If you didn't check it when you installed it, you might want to stick your hand around the flange at the top and bottom of the flange. Mine was leaking at the top and botton, I had to use silicone sealer and the copper gasket to get mine to seal. You cant hear the leak, but you can feel it for sure.

Brian

 

That is a great explaintion. I think I have some understanding now. Do most A/F controllers have a digital screen that displays the measurement in mvolts, or do they use a different measurement unit?

I have not checked the flange after I tighten it orginally. I will check it again after the pipes cool down. Thanks for the heads up. Thanks for your reply.

 

The air fuel controller dont read O2 voltage as a normal feature. The SAFC2 does have an unused input that you can use to tap into the O2 sensor. It will read the O2 voltage for you. The HKS Super AFR does not have this though. You can alway tap into the wires and hook up a voltmeter like we used to do on the DSM's. I would hide the wires and hook up the voltmeter when I would go to the track to tune it. Or you can get the Apex turbo timer that has this neat feature built into it.

The SAFC and SAFC2 both have digital blue screens that will display MAF signal, RPM, Throttle postion, and other inputs that it is tapped in to. The MAF signal is measured in Hz (frequency). The karman Vortex MAF device outputs this frequency change as the air flow increases. This is a useless number to you as far as tuning goes. If you monitor ths number, you can tell if your last mod had an effect of not. If the max Hz number increases then you are injesting more air. This is about the only useful feature that I can think it would be good for.

Brian

 

Actually the s-afc 2 is preset for stage of ours.