Stock and performance exhaust systems are designed for maximum power at a specific rpm. It’s not really something you can change during a race, and we know that compromises power at other rpm. Racers don’t like to compromise, so MSD offers a new Programmable Water Injection system so you can tune your exhaust to match any rpm!
By injecting water into the exhaust chamber at lower rpm, the density of the exhaust pulse is increased which slows it down. This has the same affect as lengthening the chamber to increase low to mid range torque and power! The Programmable Water Injection system uses MSD’s Pro-Data+ Windows based software so you can easily program how much water and at what rpm it gets injected into the pipe. The programming features allow you to inject water from 0 to 100 percent anywhere from 500 rpm to 12, 000 rpm.
The kit comes complete with spray nozzles, solenoid, heat resistant hose, programmable controller and software.
MSD’s Pro-Data+ software allows you to easily program the Water Injection points from your PC!
Programmable Pulse Width
Modulated Water Injection
Part Number for complete kit (PN 42590)
Includes control unit, water solenoid,
and remote mount spray nozzle
Injecting water into an exhaust system fools the engine into thinking it has the best of both worlds.
Exhaust systems cause racers to compromise their engine’s power. Exhaust systems are designed to be tuned to deliver maximum power within a specific rpm range. Performance can be gained by using the exhaust pulse waves to create pressure variations which have an effect on the rate as the exhaust gases exit the combustion chamber. The problem is that you are limited to that one power band which compromises your power!
Fortunately, MSD offers the Pulse Width Modulated Water Injection Control Kit that allows you to modify the exhaust at programmable rpm points by injecting water into the pipe. Introducing water to the exhaust alters the exhaust pulses thereby modifying the back pressure! With this technology you can “tune” your exhaust system throughout the rpm range of your engine.
For example, by injecting water into the exhaust chamber at lower rpm, the density of the exhaust pulse is increased which slows it down. This has the same affect as lengthening the chamber to increase low to mid range torque and power!
The MSD PWM Kit takes the engine rpm signal and processes it through a digital controller which pulses a solenoid to allow water to enter the exhaust chamber. The system can be installed on virtually any watercraft and features dip switches for easy adjustment of the rpm activation points. There are also bright LEDs that alert you as to when a solenoid is pulsing water into the system and to confirm a solid trigger signal from the ignition.
There are two systems available, a single and a triple channel system. Each are supplied with spray nozzles, solenoids, heat resistant hose and the controller.
Replacement Parts
Solenoid PN (4340)
The electronic switch that pulses the water to the spray nozzle.
Water Filter
Made from impact resistant nylon with 3/8” barb ends. A clear bowl and removable filter screen allow easy inspection and cleaning.
3/8” Inlet (PN 4335)
1/2” Inlet (PN 4336)
Remote Mount Spray Nozzle (PN 4341)
The brass 1/16” NPT spray nozzle that attaches to an 1/8” hose from the solenoid.
Direct Mount Spray Nozzle (PN 43411)
The brass 1/8” NPT spray nozzle that mounts to the solenoid.
Replacement Parts below 
Fortunately, MSD offers the Pulse Width Modulated Water Injection Control Kit that allows you to modify the exhaust at programmable rpm points by injecting water into the pipe. Introducing water to the exhaust alters the exhaust pulses thereby modifying the back pressure! With this technology you can “tune” your exhaust system throughout the rpm range of your engine.
