Originally Posted by SpringHillSRT-4
how much does water injection actually help? (IE how does it affect a/f and hp/tq)
There is no set rule. What I have seen/logged on a stock turbo running 18-20PSI, is that each degree of Charge Temp drop resulted in 1hp increase.
This was with a IC cooler (co2 type).
The same data was backed up by the intercooler shootout results posted on srtforums...basically 1hp per degree drop.
So basically, the gains will depend on how bad your charge air temp is. Things go down hill REAL QUICK with temps over 100deg.