you would need a new fuel rail due to the fact that MOST aftermarket high flow injectors are of the top feed variety. You will not be able to simply swap stock flow rate injectors for Higher flow rate injectors without software modification. Your stock computer will be holding the new injectors open for the same time as the stock injectors, but since they will be of of a higher flow rate they will be injecting a much higher volume of fuel causing your car to run waaaay too rich...for example. If you were to swap the injectors as you propose you will be running (720-550)/550 = 31% more fuel from your primaries and (1220-720)/720 = 70% more fuel from your secondaries, assuming the fuel pump can provide it, and the injector opening times remain the same. Therefore you can not simply swap injectors without modifying the computer to hold the injectors open for that percentage of time less then stock, assuming you want the same fuel supplied. NOTE* due to the higher inertia of the pintle valve in high flow rate injectors the actual fuel supplied will be somewhat less then the figures quoted if the pulse width is reduced by that percentage, but that is irrelevant to this case cause it will still be too significant a departure from stock to function without software modification...My suggestion is to simply replace the o-rings in the current injectors and call it a day
Linear Mode
