As mentioned, two individual solenoids are involved, one for nitrous and one for the extra fuel shot. Loosely install a 1/8" x 1/8" NPT male nipple into the outlet port of the nitrous solenoid. Loosely install a 1/4" NPT x 6AN nitrous filter into the inlet port of the nitrous solenoid. Trail-fit the solenoid, nitrous filter and the 1/8" x 1/8" NPT nipple into the nitrous distribution block. Note the orientation of the fitting and solenoid. Disassemble, coat the NPT threads with Teflon paste and reassemble, tightening the connections to achieve the desired mounting positions. Perform the same procedure with the fuel solenoid, using the 1/8" x 1/8" NPT 90-degree fitting into the fuel solenoid outlet port and the 1/8" NPT x 4AN fitting into the fuel solenoid inlet port. When installing the nitrous bottle in a vehicle, pay attention when determining the route for the 12' section of 6AN hose, making sure that it clears exhaust, suspension, steering, wheels, electrical lines, etc. Attach the 6AN nitrous supply hose to the nitrous bottle valve adapter. Purge the nitrous supply line by wrapping the solenoid end of the hose with a clean rag. Point the hose away from yourself and others, and briefly open the bottle valve. Attach the nitrous supply hose to the nitrous solenoid inlet port. NOS recommends that the primary fuel line for the nitrous system should be a dedicated supply to feed the nitrous system only. In other words, the nitrous system's fuel line should be fed by a separate fuel tank/fuel cell. This will require a dedicated fuel pump and pressure regulator capable of handling the engine and system demands. If the nitrous system is under-fed or runs dry of fuel, and nitrous-only is injected into the engine, catastrophic engine failure is a certainty. In short, if the engine is wailing and you activate the nitrous system at WOT, and no extra fuel mixes with the nitrous, the engine will go "boom" and that's the end of that. While it may be OK to have manual control of the nitrous switch while the engine is on the dyno, when the system is in the vehicle, a microswitch must be used at the throttle body linkage, so that the switch makes contact and opens the system only at WOT. The NOS kit includes this microswitch and an adaptable mounting bracket. A driver-activated NOS arming switch is to be mounted in the cockpit, allowing the driver to arm and ready the system.


The NOS instruction manual provides a detailed step-by-step regarding wiring the system. Here's an overall view of the wiring hookups: From battery positive, an orange wire with an in line fuse is connected to the system's power relay via the system's wiring harness connector. From the relay harness, a green wire goes to chassis ground. The harness blue wire runs to a two-wire connector that runs to both one of the fuel solenoid's red wires and one of the nitrous solenoid's black wires. The extra black wire from the nitrous solenoid and the extra red wire from the fuel solenoid both go to ground. The relay harness red wire runs to the microswitch. From the microswitch, a wire is connected to the No. 2 terminal of the arming switch. The No. 1 terminal of the arming switch goes to ignition-switched 12 volts and the No. 3 arming switch terminal goes to ground.


Problem: No change in engine speed when the fuel solenoid is activated.

Cause: System is wired incorrectly; the fuel line is restricted; or the fuel solenoid has malfunctioned.

Problem: Change in engine speed when the nitrous bottle valve is opened.

Cause: Malfunctioning nitrous solenoid.

Problem: Engine runs rich when the system is activated.

Cause: The bottle valve is not fully opened; low bottle pressure; the bottle is mounted improperly; the nitrous filter is plugged; mismatched nitrous/fuel jetting; excessive fuel pressure; loose nitrous solenoid wiring; or malfunctioning nitrous solenoid.

Problem: No change in performance when the system is activated.

Cause: The system is wired incorrectly; loose ground wire(s); malfunctioning push button; no power to the arming switch or malfunctioning arming switch; malfunctioning microswitch; or overly rich fuel condition.

Problem: Engine detonates mildly when the system is activated.

Cause: Excessive ignition timing; inadequate octane fuel; spark plug hat range too high; too much nitrous flow; inadequate fuel delivery due to plugged fuel filter; crimped fuel line; or weak fuel pump.

Problem: High-rpm misfire when system is activated.

Cause: Excessive spark plug gap; or weak ignition (check all ignition system components).

Problem: Surges under acceleration when system is activated.

Cause: Inadequate nitrous supply (check bottle weight); or bottle mounted incorrectly.


1. Never attempt to start the engine if the nitrous has been injected while the engine was not running, as this can result in an explosion. Disconnect the coil wire and turn the motor with wide-open throttle for several revolutions before attempting to start.

2. Never permit oil, grease or any other combustible substances to come into contact with cylinders, valves, solenoids, hoses or fittings. Oil and certain gases (such as oxygen and nitrous oxide) may combine to produce a flammable condition.

3. Never interchange solenoids or other components that are used for one gas with those used for another gas. Doing so may result in an explosion.

4. Never change the pressure settings of nitrous bottle safety valves. Increasing the safety valve pressure settings may create an explosive bottle condition.

5. Be sure to identify the gas content on the NOS label on the bottle before using. If the bottle is not identified regarding the gas contents, return the bottle to the supplier.

6. Do not deface or remove any markings that are used for bottle content identification.

7. Nitrous bottle valves should be closed when the system is not in use.

8. Keep valves closed on empty bottles to prevent accidental contamination.

9. After storage, open the nitrous bottle valve for an instant to clear the opening of any possible dirt or dust.

10. Never force threaded connections. It's important that all threads on valves and solenoids are properly mated.

11. Only use nitrous oxide at wide-open throttle and at engine speeds above 3,000 rpm.

12. DON'T use Teflon tape to seal NPT threads when installing nozzles, distribution blocks or solenoids! Instead, use Teflon-based paste. Small bits of excess tape may enter the system, causing a restriction that can result in catastrophic engine damage.

13. Don't inhale nitrous oxide! Death due to suffocation can occur. Also, don't let nitrous oxide contact your skin since this can result in severe frostbite.

14. Don't use octane boosters that contain methanol. This can result in damage to the fuel solenoid, which can lead to catastrophic engine failure.

15. Don't allow nitrous pressure to exceed 1,100 psi. Excessive pressure can cause swelling or failure of the nitrous solenoid plunger.

For more information on NOS Nitrous Oxide Systems, call (800) 652-0406, ext. 16414.