Port injection - frequency of FAV

[makro86]

Hi guys,

Long time HFS-4 v1 owner here - the system is great and it hasn't missed a beat. I've been using it with one pre-TB jet up to this point and am now looking to go to port injection for a new engine I am completing at the moment.

I have been discussing the port injection concept with my mechanic friend who is also looking at purchasing a HFS-4. We've searched the forums and web in general to try find some information on this, however have not had much luck in solving the following.

It seems the recommended frequency for the FAV is approximately 30Hz. My assumption here is that the HFS-4 will also be controlling the FAV at this frequency. It is a fixed frequency and the HFS-4 uses PWM duty cycle to regulate the amount of WM injected at any point.

So when switching to a port injection configuration, this leads us to the following scenario...
RPM: 9000
FAV outlet connected to port injection manifold with 4 outlets, 1 to each intake runner.
9000 / 60 = 150 revs per second.
150 / 2 = 75 intake strokes every second, 1 every 2 engine revolutions.

Now if the FAV is injecting at 30Hz, wouldn't that result in the injections of WM being out of phase with the engine?
I can see from the great results that people have with port injection that it definitely does work, so I'm not doubting that, however we are really interested in how it actually ends up working.

My only guess here is that the pulse from the FAV is somehow spread between the intake events.

Also, what is the highest frequency the FAV can be run at? My friend is looking to use his Motec to directly control the FAV as a supplementary injector. To state the obvious, frequency and duty cycle is going to change dynamically as the RPM increases, so we're looking at something like a 65 - 75 Hz / pulses per second rate for the FAV.

What would be the best practice for this type of setup to get the best distribution of WM across all cylinders?

Any guidance or correction to my logic above greatly appreciated.

Regards,
Matt