On any direct injection motor there is a limited time when the fuel can be injected into the motor so that it has time to burn and produce the most amount of work it can. The rest goes up as heat energy (EGT). There is a limit in the engine as to how much heat energy it can absorb (ECT). All these play a big part into the questions you've asked and they need to be answered before you can answer the questions you have posed. Once you work through these questions the next would be injector flow time and fuel pressure as they go hand in hand.

 

Once you work through these questions the next would be injector flow time and fuel pressure as they go hand in hand.

This is sprimarily what I was driving at.

Lets say this thing can take as much heat as the injection system can dish out. I guess basically what I'm asking here is what is the biggest shot of fuel these stock injectors can make, and how fast can they do it? At what speed will the injection system fail to keep up with the bottom end, AND at what speed does the bottom end introduce itself to the pavement?

 

speed limits

The input shaft on the alli is going to have issues at about 5k.. Much over that and things can get exciting.. I think that is the limiting factor, no the injectors.. Diesel also burns slow vs gas, so power is going to start to drop at higher rpms, while gassers (bikes) can turn 12k or faster.. There is also the cams to consider, they are set from the factory to run idle to about 3.5k..

 

According to my scanner, on a stock engine the limit of fuel deliver is 80uL/injection. That probably equates to around 300 hp at 3250 or so. I'm sure the tuners allow much more. I seriously doubt that with stock delivery there is any drop in rail pressure at governed rpm unless the fuel filter is getting restrictive.

 

There will be artificial limits built in to these diesels. A diesel that is improperly governed will "run away." Unlike a gas engine, a diesel will destroy itself by nature - without proper safeguards. Drive the pump faster and the RPMs will climb, when the RPMs climb, it will drive the pump faster, etc. There's a lot more to it, but the bottom line is that your diesel has built-in safety overrides. Otherwise the sky's the limit. No pressure loss. Could blow the ends off the injectors before it explodes, though....

 

The amount of time that you have to put fuel into the cylinder is the limit on engine speed. As the engine RPM goes higher and higher the time gets shorter and shorter to complete the processes. So from the intake stroke, compression stroke, power stroke and exhaust stroke time is the limiting factor. If any one stroke does not have enough time to complete the power will become limited. 6000 RPM is about the limit of a diesel engine due to just these factors. Then there is all the mechanical limits due to the harmonics within the engine you need to deal with as well.
There is no straight forward answer to your question until you solve all the issues list above. If you want a simple answer that solves for all these things it's not going to happen but you can get some best guesses.