Water Injection System
To control detonation in the 16V turbo at elevated boost (1 bar+) and maintain serious spark
advance for peak HP we have developed a custom water injection kit to suit the 2.3 litre Volvo
Components are all standard over-the-counter items.
Reservoir for the Ovlov.net racecar is an 8 litre nylon garden spray, complete with inbuilt
pressure pump, graduated filling scale, and 45psi pressure relief valve (US$20). Pump is a 12V
SHURFlo marine diaphragm pump model 2880-723-344 available from any boating supplies store at
around US$100. A SHURFlo 0.7 litre accumulator model #181 (US$50) maintains system pressure and
prevents the pump cycling too quickly between its high and low pressure switches.
Click either image for a larger view
Under the hood, a 12V solenoid petrol stop valve (US$20) stops flow until the desired boost
pressure is reached. The solenoid valve can be opened by either a signal from an aftermarket ECU,
or from a pressure switch connected to inlet manifold boost pressure.
Click image for a larger view
We run a "normally open" oil pressure switch calibrated to 30psi (US$40) between the stop
valve and the nozzle so a green light on the dash indicates <30psi pressure at the nozzle
under turbo boost (and hence water injection operating). No green light at >10psi boost -
The injector nozzle is a Spraying Systems
Co. all-brass UniJet TX with Size 6 spray tip, tip retainer, TT male body and 50 mesh screen
strainer, all for about US$10. We made up an alloy plate nozzle retainer, which holds the nozzle
against an O-ring into a neat hole drilled in the inlet pipe between I/C and throttle body.
Anodised pipe fittings plus nylon braided pressure hose of various diameters finish off the
installation, at around US$100 for the odds and ends.
The UniJet TX Size 6 nozzle (by our testing) delivers 400cc/minute into free air at average 3
bar pump system pressure, and from the Spray Systems flow chart, delivers about 320cc/minute into
the inlet manifold at 1 bar boost. The SHURFlo pump cycles between 60psi (cut-off) and 35psi
(start-up) charging the accumulator relatively independent of water injection usage.
Contact us for further details of a kit for your
application. As the basic components are available worldwide, you can purchase these from your
local supplier. We offer any components you aren't sure about, plus fit-up, testing and