how come i RARELY see AFC's under Z owner's mod lists? it such a popular mod in the import community im surprised there is not a lot of 350 guys tuning with this. is there a conflict with the piggy back and the computer? is it turning out that tuning it just isnt bringing good results? what gives?

 

I'm using it (SAFC2). Its okay. Modifies MAF signal, can work with MAP signal, if you install it (read here). Monitors couple of other signals - RPM, throttle, knock. Of those, RPM and throttle are used to determine MAF signal correction. Two positions of throttle can be programmed (referred to as 'low' and 'high') in percent throttle, and SAFC2 will do linear interpolation of the in-between values. RPM points are adjusted (as +/- percent) in 500rpm increments (or was that 600? I don't recall...) with same interpolation for in-between values.

Does not correct timing, does not adjust fuel delivery (duty cycle of injectors), so it is only useful as long as MAF signal is not corrected to above 5V (max).

 

Because our ECU has a variable coded into it allowing it to modify its own map to a point.

i.e. it sees more air, it will add fuel... and vice-versa. Meaning, if you tune your car with the AFC while its on a very aggressive map, yet it changes over to a more fuel conservative map... the afc is useless.

Nissan ECUs since the `96 Z32TT have been like this... a constant headache.

 

Scary thing, I wish I knew how it really works... I mean, SAFC tunes the car by tricking the air flow. Are you saying that, given different circumstances, the ECU will apply X amount of fuel for certain ariflow value, while in another case it may apply Y amount of fuel for exact same airflow value? If that is so, I'd like to know why... anyone?

 

Sadly, they dont work on newer import cars, the ECU's are too smart for them.

 

The reason many of us arent using the AFC's is becuase most of the F/I community is using an eManage, TS Reflash, or Unichip device. Those methods are much safer and far more accurate and powerful than an AFC.

An AFC does its work my increasing or decreasing MAF voltage, and by default, tricks the ECU into thinking there is more air coming into the engine..hence increasing fuel.

The problem with this, is that AFC's can modify voltage to the point that our ECU will go into limp mode. MAF manipulations also have the unwanted effect of increasing timing...not good...especially on F/I cars.

Chris was one of the first guys to put an eManage on an N/A 350z...maybe the first. I think this solution much better. Using the greddy injector harness, you are actually adding Injector Pulse Width directly to the stock ECU single, rather than tricking the ECU via MAF manipulations. It's a much more refined, accurate and elegance solution to fuel enrichment.