Limits of the Aquamist HSV

[gilbertg]

Folks,
I'm looking into using the FIA2 & HSV in a 4 cylinder, 4 stroke, 9000 rpm application but simple math may prove that the HSV will be inadequate for the task:

Two injectors will fire per engine revolution in a 4 cylinder, 4 stroke application hence the HSV will need to fire at 9000 x 2 = 18000 times per minute. This equates to an operation frequency of 300Hz. The HSV is specified up to 250Hz meaning that is this application the valve will be held fully open from 7500 rpm upwards.

If this is true then I will not be running enough water at the higher rpm and usually, a held open solenoid is a bad thing due to the heat generated in the coil which can lead to damage.

Am I misunderstanding how the FIA2 works? I know some are running the FIA2 in this application already but is the system actually working correctly? Will the FIA2 error light be on when the HSV is maxed out?

If my understanding of the FIA2 is correct then there are theoretical limits based on the number of cylinders ?.

4 cyl = 7500 rpm (6000 rpm @ 80% duty)
6 cyl = 5000 rpm (4000 rpm @ 80% duty)
8 cyl = 3750 rpm (3000 rpm @ 80% duty)

Someone please correct my understanding of this system!

Thanks,
Giles

[Brad]

The FIA2 will only be connected to one injector so it will fire just as often as the fuel injector. Works every time. The highspeed valve can be used as a on and off solenoid if you want it is very tough.

[gilbertg]

If it only fires when the injector fires then there will not be water for the other three combustion cycles or is the assumption that there will be adequate mixing of the water and air to provide a proportional mix of water/air?

[Brad]

I do understand what you see. But it does work very well. Placing the nozzle before the throttle plate seems to solve that problem. If the standard method does not work for you let me know as there are ways to wire some other components in but they are realy unneeded.

[Forum Admin]

While the aquamist jets do atomize very well, the water droplets will be varying sizes. The different sizes travel at different speeds through the induction system. Despite the pulses that do not match each and every induction stroke, with a sufficiently long induction path, the pulse will result in a steady concentration of water at the plenum, runners and cylinders based on my prior experiences. Though my experiences have only been to 8k.

If this does prove to be a continuing concern, one solution is to have a single fia2 off one injector drive two jets spaced a couple inches apart, this will further serve to smooth the concentration. I have recommended this on very short induction paths before to address the concern you raise, which is very valid theorectically but has not been shown in application to be an issue since most are injecting more water than the bare minimum necessary to suppress knock.