Will a fuel pressure reg make my injectors "bigger"?

The EEC actually makes adjustments at part throttle, but it will apply whatever it learns to all throttle positions, including WOT. It may be using tables to tell it what A/F ratio it wants, but it'll be using KAMRF (long term fuel trim) to tell it how to get that A/F. So FP is going to be a temporary fix, IF you are using it to get a richer mixture. If your injectors are not big enough, and you're running lean, then upping the fuel pressure will allow them to flow enough fuel for the EEC to compensate and get you the correct A/F ratio.

Dave

it will work. like they are saying. your computer, using your o2s, will adapt. it will shorten up the duty cycle.

so at wide open throttle you need 105% right now but obviously it cant go over 100 and you will fall lean. if you fatten up the pressure. the injector will only need 95% duty cycle to supply the same fuel. and 95% is possible.

i think some of the other responses think you want to richen the car up. your just trying to get it to not run out of injector on top end.

after you adjust the pressure, it will run too rich for a couple of days till the computer compensates. and you do want it to compensate.

what I heard if you make the fuel pressure to high, it will mess up the spray pattern

Too low and it'll hurt the spray pattern.

The eec will not "adapt" to FP at WOT, like a previous poster said. It will indeed adapt at part throttle - but just pull the battery cable and reset the EEC so it will learn the new part throttle mixture anyway. Trust me on this - people have been doing this for 15 years with great success, and with the EEC IV, it works great.

Think about it, with the idea of WOT adaptive, the FMU from superchargers would have never worked because they just kicked fuel pressure up in relation to boost....

My 2c

P.S. Without a dyno with wideband O2, your are pissing in the wind buying injectors or adjusting fuel pressure. Get a regulator on it and get it on a dyno if you are concerned. Spending 3-400 dollars here and there willy-nilly makes no sense at all and I would say that 50% of the people that purchase 24lb injectors for their mustangs did not need them, they needed another 400 dollar bolt on...