I have searched and think I understand but just need a little clarification on VFAC vs. Piggyback vs. Stand Alone.

What I do understand in short:
-A VFAC is only good for WOT tuning due to the ECU relearning at anything less the WOT.
-A Stand Alone can be tuned regardless of throttle positions because it is 100% programmable and completely replaces the stock ECU.

What I don't understand:
-Does a Piggyback suffer the same issues with the ECU relearning as the VFAC does or is it capable of maintaining a tune at all throttle positions?

I am assuming that a Piggyback doesn't have the same issues as the VFAC because these are typically what come with turbo kits and I can't imagine using one of these kits if you have to reset your ECU all of the time but that is just my assumption.

Sorry if this is a noob question but my search was inconclusive...

 

VAFC and a Piggyback are basically the same. For lightly modded S2K's i'd go with a VAFC, and for a built FI S2K standalone is the only way to tune!

 

The VAFC is a piggy back. But it doesn't control injectors directly. It alters the MAP signal to the computer and expects the computer to work in a certain way.

Other piggy backs such as the E-manage Ultimate and AEM FIC control the injectors directly and give a lot more control.

 

Are you sure that the ECU will relearn with the VAFC? So, what's the point in spending money on a tune with a VAFC if the ECU will just "reset" itself? Or can you just reprogram the ECU with the VAFC whenever you want?

 

you just tune WOT only, it's a fixed ecu map not dependent upon externalities like temp, throttle position, air fuel ratio, etc...

 

let me focus the question a little more. Does a Piggyback unit such as the E-manage Ultimate maintain it's sub-WOT tune or do you have to keep resetting the ECU?

 

It will maintain sub-WOT tunes