New to injection

[UpgreyD]

Hey all

New guy here, came to learn all I can about water injection

A little about my project:

2007 wrx 2.5L EJ55 USDM sedan

current engine mods:

Cobb Access port stage 2 ECU tune - stock intercooler and TD04-13T turbocharger with 4" bellmouth turbo downpipe mated to a full 3" catted exhaust at 16psi by 4500rpm.

Plus additional irrevelant suspension mods.

So, what I'm looking for is some education and guidance.

In the future, I'm looking to add a larger intercooler, a larger turbocharger with a possible 49lb or 52lb compressor wheel and internal wastegate, other relevant fuel upgrades and of course Aquamist.

Currently, I'm confused as to what the differences are between the HSF-3 and HSF-6. Looks like the HSF-3 gauges flow based on a PW modulated signal from the fuel injection cycles in the ECU? How does the HSF-6 gauge this? Looks like there's an additional flow control module?

I'm looking to also run an electronic boost controller with a 3-port solenoid. Maybe the AEM tru-boost or turbosmart e-boost2. How can I run this system in parallel with an aquamist system to allow the boost controller to switch to wastegate pressure should the water/alcohol injection fail as an added failsafe?

thanks in advance