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Chapter 5 Alternate Sensor, Actuator, and Switch Components
1.
In some racing applications, “pushbutton solenoid” activation is preferred. In such instances, the solenoid is connected to ground
via a pushbutton momentary switch P/N 15610NOS. Almost all multi-point fuel injection systems are provided with throttle
position sensors. NOS has throttle position sensor
controllers that activate the solenoids, according to the sensor voltage output.
This form of solenoid activation procedure is
commonly referred as “TPS activation”. Such devices are more accurate than the
microswitch.
2.
NOS offers fuel pressure safety switches. These switches only allow the nitrous and fuel solenoid to be activated, if a safe fuel
pressure is existent in the enrichment fuel supply system.
3.
Activation of nitrous at low RPM levels can be detrimental to the engine performance and engine life. The RPM window activation
switch only allows the nitrous and fuel solenoid to be activated if a safe RPM value has been reached. Some factory engine
control units cut off the ignition if a maximum RPM level is reached. Although the engine is still at WOT and the solenoids are
activated no nitrous and fuel is combusted. When the engine reaches safe RPM levels ignition is restored but excess fuel and
nitrous are present in the manifold. Some applications may even cut the fuel injector to limit engine RPM. Because the engine is
at WOT, the nitrous solenoid is still open thus generating an extreme lean condition. Under both conditions engine damage might
occur. The RPM window activation switch cuts off the supply of fuel and nitrous until safe RPM levels are reached. The low and
high RPM values can be trimmed according to the application.
Chapter 6 Routine Maintenance
6.1 Nitrous Solenoid Filter
When nitrous bottles are refilled, they can become contaminated with debris if the refiller does not have adequate filtration in his
transfer pump mechanism. Contaminants in the bottle will eventually become lodged in the nitrous solenoid filter fitting.
You should periodically (after every 20-30 pounds of nitrous usage) examine the mesh in the nitrous filter (sold separately) for
debris. To clean the filter, follow the following steps:
1.
Close the valve on the nitrous bottle.
2.
Empty the main nitrous feed line.
3.
Disconnect the main nitrous feed line from the nitrous solenoid.
4.
Remove the nitrous filter fitting from the nitrous solenoid.
5.
Remove
all
PTFE paste debris from the solenoid inlet port threads and from the nitrous solenoid filter pipe threads.
6.
Examine the mesh in the nitrous filter fitting for contaminants. Blow out debris with compressed air, if necessary.
7.
Apply fresh PTFE paste to the nitrous filter pipe threads. Reinstall the filter in the nitrous solenoid.
8.
Reconnect the main nitrous supply line to the nitrous solenoid.
6.2 Nitrous Solenoid Plunger
6.2.1 General Information
The seals used in SNIPER nitrous solenoid plungers are constructed from materials which are designed to be used with nitrous oxide.
When kept free from fuel contaminants or from over pressurization, they should provide trouble free performance.
You should periodically (after every 20-30 pounds of nitrous usage) examine the seal in the nitrous solenoid plunger.
The seals used in SNIPER nitrous solenoid plungers are designed to work at pressures up to 1100 psi. Exposing the plunger to
excessive pressure (whether the vehicle is sitting or in-use) can result in the seal in the plunger swelling or in extreme cases
disintegrating.