[Neil Harvey]

The MFI squirt is relatively short compared to time when valve is open though and it can retarded or too early. I feel that mine is just right, and pump is just about as good as I can get it.

Even more reason why you would want to time the injection with the valve opening. If its short, I would think you would want the middle of the injection to be right when the intake flow is at its best.

Why accept that the two injection timing points that have been used, are what you need and with different cams and settings. Seems like a huge compromise going on. If you change the characteristics of the intake flow and not the injection, you may be leaving a lot of performance unseen.

How does the pump builder know how the airflow is working in your manifold? Seems to me its an historical injection timing of what worked in years past. You start changing the manifold, Valve timing and opening duration and not the injection timing, you could be way off the performance, the engine could make.

I'm not saying I know this to be factual, but its something I would look into if it was me, and not leave it to the pump guy. I would ask him the fuel flow numbers and the opening times in crank degrees. Then with air flow numbers, cam duration and piston shape I would figure out the best time to inject the fuel. It very well may be the times you suggest, but I would check this and not take it for granted. In an electronic engine the injection timing and the pulse width play a huge role in power production. In your case I figure you cannot change the opening time as much, but you certainly can change the time it opens, or closes or choose the middle of the event.

I would bet that a lot of the fuel is dumped on the backside of the valve waiting for the valve to open. You then get puddles of un atomized fuel and droplets of fuel on the cylinder wall that don't get atomized very well and end up out the exhaust. Then the efficiency goes down as the energy in the fuel is been wasted.

I could be completely wrong here, but I cannot get my head around cam changes and set injection timing.