Tex, no CAI but coolant, tranny, Oil Guard, and a 5 micron NAPA hydraulic filter on the output of my ESP luber with strong magnets everywhere.

My thinking on fuel pressure was that raising it would give you higher pressure before the intensifier piston pushed it into the cylinder, higher pressure during the injection event, and that would give better atomization of the fuel. Just using a simple theoretical example, if fuel pressure is 60 psi from the pump and it is raised to 18,000 psi during injection then you have a multiplier of 300. Well then, and again I'm using simplicity because that's about as much as I know about all the ins and outs of injection, if you raise fuel pressure to 65 psi you should get 19,500 psi during injection and 21,000 by going up to 70 psi... Hey, it's just a theory. That's why I was asking the questions I did. I really don't know if it works that way or not but I was sure someone here would.

The same idea was at play with more holes of smaller size in the nozzle. That was why I was asking about sizes and patterns that matched the original total area of the stock injector nozzle holes. Same fuel through more holes of smaller size, would it give you better atomization and in doing so help both power and fuel economy?

The last thing is that my engine is now two generations back from current cutting edge stuff and may start to loose support from the aftermarket developers working on the "latest and greatest". It is the last engine without the cursed DPF though. I bought my XCal 2 from Matt with lifetime support but downloaded all the tunes for my calibration. I have the ASE tune running pretty much all the time.

 

Well iwth programming to help with pulse width and other things, you might be able to eeck at more, but not just with the increase of fuel pressure alone. Not on these trucks. Let's put it this way, you get modified injectors, more often then not the blow-off valve is closed. Now if they do nothing else to it other then that, that'll get you about 15mm^3 more fuel, but the computer doesn't know what to do with that, what results is more of what people call a "hot cam sound". Cool sound, but not doing a whole lot, sure some of that extra will get burned and used, but it won't be as efficient.

With just increasing fuel pressure I would relate that to a water pump. Let's say for irrigation you put down 3" pipe and that translates let to 4hp pump(I'm just pulling exact figures out of the air, I used to know, but old age has taken that from me), but you up the pump to a 6hp, however you still have the 3" pipe. Your not gaining anything except that the new pump won't be working as hard, that's about it. Not going to be getting any more water to the yard any quicker.

Yep, pretty much won't be any truly new stuff coming out for our enignes any more unless there developes a niche market for the 6.0. About the only support with any newness we will get is with tunes.