Any questions you have before you begin buying, building and installing.
We are currently running a 2l. 4cyl tractorpuller with 5bar boost, water injection and a diesel consumption of 600l/hour and are planning to build another running methanol fuel and a spark so a pretty new game and therefor asking for some feedback on the plans. (both engines based on the PSA DW10 2.0hdi engine)
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A pretty basic setup except for the injector wiring and added exhaust temperature, fuel and waterinjection pumps are mechanical.

The waterinjection is the most tricky part since the speeduino still lacks support but following one could setup the waterinjection like that and add some form off waterpressure control based on temp or boost.
Best way would be a code modification to add an extra input source for the second/staged injector but hadn't looked at the code itself yet, the input source could be switch or PWM signal to start a secondary mapping for the water injector.
On our current machine we have a datalogger based on a Mega with a thermocouple addon board for temps using the SPI bus for communication but have no idea or the SPI bus is still available but instead off using a digital pin for input source that would also be an option.
In any off a code based waterinjection that would mean a pretty big change in code I presume since using 2 types off "fuels" would require 2 types off mappings...
Welcome! There are many ways to handle proportional water injection of course. The way you have your system laid-out lends itself to one method for ratiometric (proportional) water injection using staged injection.

In this case, the staged secondary injector "fuel" is water. Staged mode would be Manual. If, for example, you wanted 30% added water (proportional to fuel), the staged WI boost areas would be set for 30% secondary injector load. The VE Table values in the same cells would be increased from correct (100% fuel from primary injectors), to +30% (130% total in cells with WI). Running, the engine would receive correct fuel (100%), plus the added 30% as secondary injector water, only in those cells.

I hope that makes sense, and additional safeties should be incorporated that are not internal to Speeduino yet. Again, there are many ways to accomplish this, and you should use a method that you feel fits the project needs and goals best. Do your thing!

Thanks David!

Actually something similar was my first thought but I didn't (still don't) understand completely when which map takes over or is added...

My initial plan was using the staged injection and a secondary fuel table set to switched on an input, convert the thermocouple signal to a PWM and feed that to the input but ran into trouble with injectors setup since whatever req-fuel value I use in staged injection I can't get any larger then 1500cc/min on both even when choosing 4000 in the req-fuel calculator so I stepped to plan B, did have a funny staged table:
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For exhaust temp control the thought was fuel table 1 at 50% and fuel table 2 at 100% so full throttle only goes to 50 unless the pin from the second is high then it goes to 100% (don't know if the pin is pwm capable btw) and start the staged injection table at 50% so the second (water) injector is only working if temp is to high
It would seem your parameter for water injection is exhaust heat. This may increase complexity of tuning or results. For simplicity (at least initially), consider tuning with fuel and water together, in areas it is shown to generally be desired by testing. In other words, assume you will always use water when you reach a specific RPM/MAP threshold, rather than a certain variable exhaust temperature.

On a separate note, I have not used much WI with methanol as the primary fuel, though I can see your interest. Keep in-mind that with some fuels, water can increase the EGT in certain ratio ranges. The NACA studies showed this tendency clearly with those fuels, and I have confirmed with similar fuels. Have you tried meth fuel with added water on your setup already? Any data to share that may support water % or versus EGT?
Thanks for your input David!

You are right, with a decent setup water could be injected static instead off an exhaust temp variable.
However when guessing the amount wrong I end up with melted pistons and other minor annoyances thats the main reason to use an exhaust temperature reading for base setup.

I know that water can increase EGT but that's with small amounts.
I have no data on alcohol fuel but I do have it on my diesel due to malfunctioning water injection, 350cc/1000injections fuel with 450cc/min water gives me 850 degree celsius in the exhaust and without water over 1100

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