EFI Subject to talk about

Modern car engine heads are designed so that the fuel injector can squirt directly at the intake valve.

A typical four cylinder tractor will share intake ports (Siamese) between two cylinders. This makes it difficult to ensure that the fuel is delivered to a specific cylinder. The problem is worse on injection, but does exist somewhat on carburated engines also.

Moving the injectors up close to the head will increase torque by providing fuel quicker upon change in throttle plate. There is a starvation in the cylinders when the throttle plate opens until the additional fuel can get to the cylinder. It will also decrease the warmup fuel required that would condense in the cold manifold.

There may be times when the adjacent cylinders have both intake valves open. I need to make sure and inject at the exact time when I can insure the correct amount of fuel goes to the correct cylinder.

I need to profile my CAM to find out these positions. Has anyone profiled their CAMS?

Dave,
Not applicable to your tractor but an idea.

Some Hondas and a few snowmobiles used to have to spark plug holes, one with a plug. You could machine a bushing to put your FI in the other hole. Or if you have enough metal, drill and tap it. It isn"t going to mess with the chamber that much. We are talking 1500rpm tractors, not 8000 rpm engines.

Never put much thought into the Siamese problem. Have to think on that one for a while longer.

Rick

that is how most new generation engines do it, direct injection, directly into the combustion chamber. Only problem is you need a lot higher pressure to make that work.

For decades automotive manufacturers have used batch firing for fuel injection, all 4 on one side then all 4 on the other side or 3 then 3 etc. The actual timing of the injector spray has little effect on overall performance.
True sequential fuel injection systems are much more complicted in design and cost.
Larger injectors, higher pressure fuel pumps, more sensors etc to deliver the required amount of fuel in milliseconds vs batch firing being able to cycle twice per combustion event.
Regarding your thoughts on the intake ports; even with no divider in the intake between two adjacent cylinders, the intake valves are not open at the same time on the adjacent cylinders so competition between them is measurable but negligible in most cases.
Timing of the injector spray is only relative to the fuel being there at the start of the intake stroke.
The ignition system decides when to fire the spark plug to ignite the mix approx 360 degree later.
If you want to try this just to say you did it then all the power to you, I enjoy reinventing the wheel on occasion myself. From a practical functional standpoint I think it would be too much work for too little gain.