Water injection Q's

[Jeremy Butts]

The water you inject is supposed to turn into steam from the heat of
compressing the air, not in the combustion chamber.  Yes, steam does take
up a lot more space than water, so theoretically, one should see a
pressure rise on the intake manifold (But of course the wastegate
compensates, and so you see nothing), But I do not know if it is large
enough of an expansion to actually spend time thinking about.
If you are not confused yet: read on

Injecting water before the turbo has drawbacks, the compressor wheel, when
it hits some of the water that is hopefully vapor, will erode.  After
doing it for a while myself (10,000 miles) I would say the compressor
wheel has a
life of 50,000 miles under hard driving with the water injected before the
turbo.  If you inject the water after the turbo, you need a pump that will
supply enough pressure to be above the intake pressure by a significant
amount, plus a solenoid of some sort.  I have used fuel injection
components to do this, but it seems the fuel pumps do not like to pump
water, they die in like 3 days.

As for the water condensing in the intercooler, i do not know, if it is an
air-to-air, I doubt it, but I have heard of fuel puddling in cold marine
air-to water intercoolers.

Jeremy Butts
still working on a water injection system
1970 240Z Carbureted turbo