have seen it setup on a 200sx
it used a hobbs pressure switch for manifold pressure
so i think it came on past 8psi
it was a car dr drift had done
it had a dash warning light for low water/meth
not sure where it injected it to, logical would say just before throttle body.
you shouldn't need to run this to take away knocking, unless you only have access to local penis fuel where you live (like the mafia). if you are getting yellow flashing engine light in normal conditions you need your tune fix, using meth/alky is only hiding the problem.
with this u can in theory dial in more ign timing and boost but once the water/meth is out or disabled you need to basically undo those temp changes otherwide it could detonate itself to death