2V, 3V and 4V injector spray patterns (as they pertain to V8 modulars)...
The 2V, EV1 style injector is a single-cone spray pattern injector. The dimensions of this conical envelope aren't known to me, but suffice it to say that it is probably in the 7-13* range, and directed at the back of the intake valve head (or as close as possible). This not only allows for the maximum amount of time to atomize the fuel, but it also cools the valve.
The 3V/4V, EV6 style injector utilizes a dual-cone spray pattern. The strategy is necessary for the same reasons as mentioned above. The fact that there are 2 intake valves and 2 intake ports creates the need to divide the spray pattern into two distinct streams. A single stream would simply wash down the wall that divides the two ports and the majority of the stream would miss the valve heads. This is not good for emissions (when you shut down the engine, that fuel that would be built up on the port walls would evaporate into the atmosphere. Our friends at the EPA don't appreciate this). And again, it also is not good for atomization and valve cooling.
The typical 3V/4V spray pattern is described with the following dimensions:
The alpha angle - This is the angle between the centers of the two streams. This angle is typically 20*.
The beta angle - This is the angle that defines the shape of each conical stream. It typical measures between 7* and 10*.
Some of them employ a third angle. This angle is known as the gamma angle, and it is the angle at which the two streams spray relative to the centerline of the injector's axis. This gamma angle is only used when a packaging solution cannot be worked out that would otherwise not require it.
Let me just say that you cannot simply look at the tip of an injector and make a determination as to what the spray pattern looks like. Most have four orifices. The technology used in the piercing of these holes is where the money is. The angles at which they are pierced and their orientation in the injector are the key.
Orientation of the injector within the engine package is key also. For the EV1 style, you can spin the injector around it's axis freely since it has only one dimension defining it's spray pattern (basically, beta). The 4V and 3V injectors need to be oriented in the package at a specific angle, meaning the connector head on the injector needs to point in a particular direction. This is usually 90* from the centerline of the crank, but sometimes it differs. This angle is called the "delta" angle. This is why you will find clips and tabs and the like which keep the injector oriented in a particular manner. It is important to not deviate from this orientation for the same reasons discussed earlier.
To add more to the confusion, there are applications of EV6 injectors that only use a single-cone spray pattern. However, in the V8 modular community, I don't believe this is the case. You might find them in other engine types.
That about sums it up, or atleast enough for what we need.
So, if you want the most out of your fuel system, be sure to select the proper injector for your application.
