©2004 Edelbrock Corporation
Brochure No. 63-0190 - DC/mc
Rev. 03/04
Catalog #70003 & #70004
Page 22 of 28
5.0
Baseline Tuning Suggestions
Utilizing nitrous oxide as a power adder is similar to a supercharger or a turbocharger in that it increases the amount of air
an engine can get over a naturally aspirated condition. There are some significant differences:
1.
Nitrous oxide is very oxygen rich. This oxygen is of a much higher density, so the opportunity to extract very high
quotients of power is high.
2.
Nitrous oxide injection does not have a parasitic load factor associated with its use like a turbocharger or
supercharger.
Meaning, it does not cost horsepower as a crank-driven supercharger or an exhaust-driven
turbocharger.
3.
Nitrous is instantaneous and their is no lag time such as what you would encounter with a turbocharger.
The most important thing to remember when looking at baseline tuning issues associated with nitrous oxide is that a lean
condition is bad. Two parameters that will keep you from catastrophically affecting your engine are:
5.1 Nitrous Bottle Pressure
...Always keep your bottle pressure between 900 and 950 psi. Yes, there are racers that
use different pressures, but the testing we did here at Edelbrock to ensure the jetting maps within this manual are
correct, was done in this pressure range. Use any higher pressure than 950 psi and you will be lean. Use any
pressures below 900 psi and you will be rich.
5.2 Fuel Pressure
...Always ensure you have between 6-7 psi of fuel pressure every time you enable your nitrous
system. We used 6.5 to 7 psi of fuel pressure to perform our jet map testing on this system. If you do not have at
least 6psi of fuel pressure going to the fuel solenoid, when it is activated, you will be encountering a lean condition.
If you were to have more than 7 psi of fuel pressure, when it is activated, to the fuel solenoid, you would have a
rich condition.
The jet map provided for your 2-Stage Performer RPM nitrous system is purposely rich, or biased to the fuel side of the
nitrous to fuel ratio. There are many different ways to jet to a specific power level. However, for the continued safe operation
of your nitrous system, we suggest you do not move too far away from the jet map listed within this manual. Catastrophic
engine failure could result.
Your 2-Stage Performer RPM nitrous system comes with matched sets of nitrous and fuel jets. These are conservative jetting
combinations, based upon 900 to 950 psi nitrous oxide bottle pressure, and 6.5 to 7 psi flowing fuel pressure. Operating
with these pressure levels should yield safe and reliable power increases.
How to Read Spark Plugs From a Nitrous Oxide Injected Engine...
Spark plugs are a window into the combustion chamber. They will tell you many things about the operation of the
vehicle. Here are some tips on looking at spark plugs to “read” what is happening with your engine:
Correct timing, mixture and spark plug heat range
Ground strap retains “like new” appearance. Edges are crisp, with no signs of discoloration. Porcelain retains clear
white appearance with no “peppering” or spotting.
Excessively rich mixture
Porcelain may be fuel-stained, appearing brown or black. In extreme cases, ground strap, electrode and porcelain
may be damp with gasoline, or smell of fuel.
Detonation
Edges of ground strap may become rounded. Porcelain has the appearance of being sprinkled with pepper, or may
have aluminum speckles. During heavy detonation, the ground strap tip may burn off. This phenomena can result
from excessive ignition timing, too high a heat range spark plug, or inadequate fuel octane.
Excessively lean mixture
Edges of ground strap may become rounded, or broken. (Under moderate overheating, the tip of the ground strap
can discolor, usually turning purple, or the entire ground strap can become discolored.)
