[rotrex]

Hello Paolo,
I cannot comment on everz question you asked, but on a few.

The nozzles themself spray in any direction you point them.
For a direct port set-up, you need to place the nozzles close to the fuel injectors and on the same side as the fuel injectors.

The spray does not like to take any turns. If you mount them on the bottom, you end up with most of the spray on the front side of the intake valves and with it very unevenly in the cylinder on the side pointing towards the intake plenum. This negates a lot of the effects.
You want the nozzles to mimik the fuel injector location (in line and same side) and idealy also direction. The latter is not as important as the location.

See also my postings in this forum:
Timed Duty : Direct Port Injection. Last page
And
JET PLACEMENT FOR AIR FLOW (POST-MAF)


The nozzles you have choosen are too small in my opinion.
I am using 4x 0.4mm Typ c jets on a engine with injectors half the size.

You are likely in the 500 to 800 HP bracket with these huge injectors depending on fuel type. I'd more look into 0.6 or even 0.7mm nozzles. It is easy to regulate flow down a bit using a fast acting valve FAV, a Aquamist product. It is controlled like a fuel injector using pulse width modulation leading to a rather linear delivery behavior. I myself use the older version calld HSV or high speed valve.

Finally I would consider working with a 50/50 by weight methanol water mix unless you run e85. For e85, the methanol won't do to much anymore in a direct port set-up.

It is easier to tune, more effective and performs at rather normal AFRs.
With a 50/50 mix, you tune to lambda 0.8 to 0.85 or a indicated AFR of 12-12.5.
Any richer than 11.8 and you lose power.
With pure water, you rather want to be a tad leaner than that, so 12-5 to 13.
Otherwise effective flame speed (speed + initial delay) drops a lot, and you lose power