You do not need G code injectors. You can run them, but they are not a requirment. G codes were introduced with the turbo model, and are refered to as "emissions injectors" which I don't know what they mean by that exactly, other than I think they were trying to get smoke reduction with them. Consequently, I don't think of them as an injector that necessarily going to produce more power. Fuel delivery is a function of the pump. All the injector controls is the PSI required before it will open, and how it sprays the fuel. Ken from DPS produces modified injectors he claims give added HP, but they do it at the expense of the spray pattern, and produce more smoke. He believes because the IDI has pre-cups, that this negates the need for a good spray pattern. I don't have any proof that they necessarily flow more fuel. This is one of the reasons some of my customers say they don't have an over abundance of smoke, where as I do since I'm running the DPS injectors. This summer I plan to revert to stock injectors to see what kind of difference I notice. I'm about half inclined to think I'm actually giving up power and economy with a poor spray pattern. Hence if G codes actually have a better spray pattern, they may produce more power than the DPS ones. I think spray pattern may equate to better timing, since a droplet of fuel is going to burn from the outside in. If it is a big droplet, the center of it will burn later than if it is a small droplet, and some of the droplets that come out of DPS injectors are pretty darn big. I suppose it is possible that oriface size could prevent all the fuel from an injection event from burning, since some of it may be lost to backpressure and expansion of the line or some other kind of compressive loss, but that would only be at full throttle, or at least very heavy throttle, and It would take quite a bit of labbing to find that out. Something I hope to pursue with my rebuilder at some point.
