ty for real life experience update

 

I tried too but no dice. Afpr worked well for what I needed

 

When I had my tuner tune my 05 with vafc2 he recommended not getting a FPR bc it would have been a waste of money! He said the stock ecu would re-learn the sequence, loop, blah blah, Im not really sure anymore bc its been a while but it made sense at the time! I just don't remember the exact explanation. The VAFC only allows you to adjust one part of the fuel system whereas the AEM or Kpro allow full adjustments to be made! I hope this helps!

 

The s2k ECU is comprised of a closed and open loop. In Open loop there is a disconnect from the ECU ability to intervene/learn. This closed/open loop transition happens approximately 35% throttle and above to WOT. In closed loop which is idle and light throttle to 35% as mentioned, the ECU has a pre set target of stoich 14.7 fueling which it will stay integral to even if you introduce more fuel through added fuel pressure, whereas Open loop will allow the motor to get the fuel you want with the added fuel pressure. The Vafc effects OPEN loop effectively only and in junction with added fuel pressure for now obvious reasons. So now with all this clarification of open/closed loop, its why an adjustable fpr does work effectively to add the fuel where its needed in open loop range of your fuel wile not running overly rich in closed loop. If all you needed was a bit of fuel with your vafc set up at WOT, the fpr would have worked great. However it sounds like he wanted to sell you and tune a very expensive system instead.