This is way off-topic from cyclone activation, but here's what I'd do (and might someday if the engine ever goes back in the car...)
I would use some of ECMlink's new "nitrous" features - particularly the ability to run dual maps, based on whether the FPR solenoid is activated or not. Tie the FPR solenoid output to a relay, which turns on the WI system. Tune the base map conservatively, without the WI, and tune the secondary map with timing advance for when it's activated.
The key here is that you can tie the FPR solenoid to specific conditions, including load factor if you want. More importantly, you can also set a knock condition (only activate with 0-7 counts of knock for example) for the solenoid to be activated. That way, if *anything* goes wrong (whether it's a WI system failure, or simply an incorrect timing or fuel setting), the system will kill the WI system, *and* revert to a safe timing map until the knock count drops, instead of only retarding timing slowly.
Once that's in place, you can add whatever fancy features you want. If you can live without a two-step, you can even use the clutch switch input to determine whether the FPR solenoid triggers (and also the WI timing maps tied to it), giving you a dual mode setup, or even use a momentary steering wheel button to make the WI function like a nitrous button. You can even tie a dual-stage boost controller to the same relay output as the WI system that will allow you to run higher boost, but *only* while the WI system is running, *and* you have low knock. If knock is detected, the system will also drop the boost to a safe level.
Basically, you have knock sensor control tied completely into the WI system and the advanced timing that goes with it. It's the ultimate failsafe system that doesn't have to rely on flaky things like detecting pressure loss or a "clog" in the WI system, and will allow you to tune the system safely.
I'd been thinking about something similar with DSMlink V2, using the nitrous control to add a static timing advance for WI instead of retard (if that's possible), but the dual maps system on ECMLink would be much more elegant, and give you a better non-WI tune instead of just a static timing retard.
Anyway, it might be pretty ambitious, and would require a lot of tuning time to do the set-up, since you'd have to completely tune the car twice (unless you dialed in the tune already before installing the WI system), but having knock control tied to a timing map seems like the safest way to do it.
Regardless of what you do, you need to at least restrict the WI system to activate only under boost, probably just specifying a minimum load factor unless you want it active all the time under cruise, or you use something like the clutch switch to manually disable it). With this setup, you cannot have a separate control "downstream" of the ECU that disables the WI, or the ECU will be trying to switch to WI maps without the WI running.
So in short, no, I would take the variables out by tying it to knock instead of to boost pressure.
The only problem I see is that unless you're logging, or paying attention, you may not even notice the power loss in a situation like driving on the track, unless you also rig something like an indicator light to the FPR solenoid output.
Quoting Hertz:
Great info on the Cyclone guys, thank you.
Quoting Dialcaliper:
The main issue with using load triggered water injection is that unless both your WOT and part throttle tuning are spot on, and the water injection system is working perfectly, *and* your load sensitive trigger is tuned for all conditions, it will be extremely difficult to tune safely (You have to individually consider every point on the fuel/timing map, and account for hot days, humidity, etc). You will spend many hours fine tuning - It's probably not impossible, but it is not something you approach lightly.
So would you advocate taking those variables out by activating water injection with boost pressure?
