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Old 13-08-2014, 12:43 PM
Alfa-Vector Alfa-Vector is offline
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Default Controling individual cylinder WI with PWM

I am planning a WI build on a ITB 4 cylinder with each inlet manifold runner having it's own jet. I like the aquamist system as they allow for PWM control of the nozzles, however I'm a little confused on the delivery method and can't seem to find the information anywhere.

What I would ultimately like to achieve is to run fully sequential fuel and water, although from the looks of things, I will have to run semi-sequential water injection.....but even the best approach to doing this eludes me.

From what I gather, water goes from the tank to the pump, followed by the WFS and FAV. In my case, there would be a 4 way manifold after the FAV and from the manifold to each cylinder. From my understanding, the FAV receives a signal pulse which activates and squirts all four nozzles at the same time? Is this correct? I find it a little peculiar if each intake port is receiving water spray every 90 degrees of crankshaft rotation.

I plan on not using the controller and relying on a third party engine management system with it's own water delivery table.

So I guess my question is this: to run semi-sequential would I need two FAVs and two manifolds; and four FAVs and four manifolds to run full sequential? Please forgive me if I've mad a stupid slip up and missed something bleedingly obvious.

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Old 13-08-2014, 05:26 PM
Richard L Richard L is offline
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Default Re: Controling individual cylinder WI with PWM

It will be difficult to implement a mutlipoint-sequential injection set up base on our existing components.

1. The FAV has to have quite low flow - around 500cc/min per manifold runner. 1300cc/min is our standard issue.

2. Detection an individual blocked jet require multiple flow sensors. Th=It is difficult to make a turbine base flow sensor that reads below 100cc/min.

3. Driving the FAV can be shared/parallel electrically with the fuel injectors if the coil impedance is matched.

Anyone of our system can receive a PWM signal form your ECU, frequency between 50-400Hz.

Water injection is rarely needed before boost. Once on boost, air speed is quite fast, distribution is not too much of a problem if the can be placed at the exit of a FMIC. Droplet distribution will even themselves out along the journey upstream.

If you are running a large amount of water, then consider a 5-jet setup, four at the runners and one at the exit of the IC. Due to the pressure differentials between the two banks, checkvalve jet is preferred.
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Old 15-08-2014, 05:47 AM
Alfa-Vector Alfa-Vector is offline
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Default Re: Controling individual cylinder WI with PWM

Thank you Richard for such an in depth answer.
So I take it, it is going to be over-complicated, cluttered and not to mention expensive to attempt such a setup.
I do assume that the best approach from here would be to run a single bigger nozzle, say, in the piping between the air filter and airbox?
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Old 15-08-2014, 06:59 AM
Alfa-Vector Alfa-Vector is offline
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Default Re: Controling individual cylinder WI with PWM

Oh...I forgot to mention that this is a NA motor....and based of my injector calculations, if I was to go down the individual cylinder path, each nozzle would have to flow just over 26cc/min at 10% mixture strength or 40cc/min at 15% mixture strength
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Old 15-08-2014, 08:13 AM
Richard L Richard L is offline
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Default Re: Controling individual cylinder WI with PWM

At those low dosage, we cannot manage those low flow rates. In sequential mode, it will have to be even lower quantity per injection event.
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