When to use

Use nitrous only when the engine is in top running condition and use it in a controlled environment. If you've been driving around on a 40 degrees C day and the engine is cooking, that's a bad time to make a 20-second nitrous blast, even if it will impress your new girlfriend. Being smart also includes staying aware of your gauges and treating your car with respect. Remember, the longer you stay wide open, the larger the load on the engine.




Safe Levels to start with

Assuming your engine is a stock engine:

• For 4-cylinder engines: a 50 or 75 HP kit (50 recommended)
• For 6-cylinder engines: a 75 or 100 HP kit
• For 8-cylinder engines: a 125 HP kit

may be considered safe levels to start with.



Using an Exhaust Gas Temperature (EGT) Gauge

An Exhaust GasTemperature (EGT) gauge is a great compliment to an air fuel ratio (AFR) gauge. Some folks tune cars based just on EGT and some just on AFR but combining both measurements is a much better way for tuning.


EGT is used for tuning and also as a warning indicator. The EGT suggests whether the AFR is relatively rich or lean. This information is most useful during wide open throttle (WOT) engine operation.

At wide open throttle (WOT):

• values between 850 - 900 degrees C (1562 - 1652 deg F) are often considered ideal
• temperatures below 800 deg C (1472 deg F) are considered too rich
• temperatures above 925 deg C (1697 deg F) and approaching 1000 deg C (1832 deg F) are considered dangerously lean and can result in excessive engine detonation (knock) and possibly burnt or melted components (valves, spark plugs, pistons, rings).

The placement of the EGT probe affects the measurement (the further the probe is from the head exhaust port the cooler the temperature can be) as does the amount of ignition timing advance (more advance can mean cooler temperatures). To get useful temperatures, the probe must be installed in the exhaust manifold (and if on a turbo car before the turbocharger). Most people install the probe near where the individual exhaust manifold branches have joined and the temperatures from each cylinder have combined.





Triggering the System Safely - Very Important

Generally, for safety and performance issues you will want the system triggered while you're at the track, at WOT (wide open throttle), and at relatively high RPM's. To make that happen, you'll typically want to wire, in sequence, several switches. You'll have some or all of the following:

• Arming (On/Off) switch
• Wide Open Throttle (WOT) switch - It is a micro switch installed on the throttle system, that activates the circuit only when your foot is on the floor, or 7/8 the way down, etc.
• Push button in the car
• Window Switch that closes the circuit only when the engine RPM is between a certain range (like 3000-6000) that you decide is acceptable
• Fuel Pressure Safety Switch (FPSS)

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