plain english please. ppl can't understand what you really mean.
you want to save fuel by adding a fuel regulator for what? this regulator is to regulate more to sustain the fuel pressure. Gti need more and more pressure during high revs.this is the benefits of fuel pressure regulator FPR.
if you want to get 100km/rm10, don't be heavy footer..drive below 2500rpm. gti fuel mapping start twice from 3000rpm and 6000rpm (cultus). thats why you can feel its powerband at this point.
to tune FPR, you must double set it during idle and moving..i can't remeber but you can check at manual. std pressure is 33-35psi and normally ppl increase to 40-42psi..this would give enough pressure during moving (approx. 22psi) BUT make sure your pump is good or otherwise, you might kill it.
for std. cultus, its sufficient amount.onli that in our case, potong condition, we must hav FPR to get the std pressure..