Water injection solenoid

[dzorde]

Received this message from MSD a while ago now, but thought everyone
interested in water injection might find certain parts of it interesting.

        FOR IMMEDIATE RELEASE
	August 22, 1997
	CONTACT: MSD Ignition


MSD PWM (PULSE WIDTH MODULATED) WATER CONTROL SWITCH
PN KT4259

Currently, exhaust systems used on personal watercraft are carefully "tuned"
or shaped to a certain length so as to produce maximum power within a
specific rpm range. The basic function of this tuning is to cause exhaust
pulse waves to reflect inside the exhaust chamber that will create local
pressure variations. These pressure variations can either help scavenge the
remaining exhaust gases or plug the exhaust port to prevent the intake
charge from entering the exhaust. The more precisely the pipe is tuned for a
specific rpm, the more likely it is that performance throughout  the rest of
the rpm range will suffer. The speed of the exhaust pulse wave changes
according to many  variables, with the exhaust chamber length being the most
critical. Since high speed performance is generally what the pipe is tuned
for, the exhaust chamber is kept relatively short. Unfortunately, this
design is a compromise which adversely affects performance at lower rpm
where the exhaust pulse wave reaches the exhaust port too early to
effectively seal the port during the compression stroke. This early arrival
of the pulse wave is especially detrimental to performance of highly
modified engines with large or raised exhaust ports.

The MSD PWM Water Control System resolves this design compromise by
effectively "lengthening" the exhaust chamber during low rpm operation,
while allowing the chamber to retain its short length tuning for optimum
high rpm operation. The PWM System operates by taking the engines rpm signal
from the stock or MSD Ignition and processing it through a "Pulse Width
Modulated" switch. This PWM switch in turn activates a solenoid which
injects water from the main water feed line into the exhaust chamber itself.
This injection of the water into the exhaust chamber has the effect of
cooling the exhaust gases, thereby increasing the density of the exhaust
charge in the chamber and slowing the exhaust pulse wave. This has the same
effect as mechanically lengthening the chamber to increase torque and
horsepower at low and mid engine rpm. Below is a graph that illustrates the
advantages of using the MSD PWM Water Control Switch. For additional
information call or write to MSD Ignition, 12120 Esther Lama, Suite 114, El
Paso Texas 79936 (800) 392-2842

Does anyone know if this solenoid they are using is really suited for
saltwater and if any jets would be required for a water injection system in
a car.  Actually does anyone know anything about this solenoid ?

Dan     dzorde at geocities.com