i heard from someone recently that those with standalone systems can tune their fuel delivery to get upwards of 25-28mpg constantly.... is this true?

 

It is false. You can lean it out, but not that much.

 

Sure, those numbers are absolutely possible, assuming that your "constantly" criteria means highway cruise. Of course, gas mileage is going to be much worse under condions of acceleration, heavy loading, adverse weather conditions, etc. FYI a stock NA FC is rated at 24mpg highway.

 

well i've found that making a low boost setting of:

Pri .50kg/cm^2, 20%
Sec .50kg/cm^2 20%

keeps the injector duty under 50%, and helps my gas mileage a lot

 

Oh, I thought you were using that clogged fuel filter as an economy lean-out device.

 

yeah, i replaced that as well as the fuel pump (went with supra pump)

i'm getting the injectors cleaned and the FPR replaced

 

mods on n/a for exhaust and intake on stock ports and whatnot help gas mileage a lot, as long as not too extreme.
frees up energy that was wasted