 Engine : Nitrous Oxide Systems
Posted by AcuraImport on Thursday, March 20 @ 00:16:04 CST
Basic Theory
Nitrous oxide injection aka. "Juice" is the quickest and most
cost effective way to boost HP and torque. The principals behind
Nitrous Oxide Systems is really quite simple. Since air is
approximately 24% oxygen, only 24% of the air your engine takes is
used by your engine in the combustion stroke. N2O is
36% oxygen by weight, and when it is stored in a liquid stated in
your bottle it is more dense than the surrounding air. It acts
like a three stage power producing process.
- Nitrous oxide is more dense than air, and as you know the
more dense a gas is the higher the concentration in a given
volume
- Nitrous oxide also contains a higher percentage of oxygen,
and because N20 is more dense that means that an engine will be
able to utilizes approximately 50% of its intake stroke opposed
to only 24%. That is because your engine can only burn as much
fuel as the amount of oxygen will allow.
- As the nitrous flashes into gas in the intake track and
cylinders it cools down dramatically. The intake charge will
normally be chilled by at least 65 to 75 degrees, and as a
general rule of thumb you can gain 1 hp for every 25 degrees
cooled. So, you can gain up to 3 hp on just the cooling effect
alone!
Now, some of you might be saying to yourself nitrous is a
nonflammable compound. Under normal conditions, you would be right
to say that. However, once heated past 570 degrees, a temperature
easily attained in the cylinders of your car, the nitrous begins
to decompose into free oxygen and nitrogen. The free oxygen lends
itself to the combustion process requiring more fuel and creating
a more powerful explosion. The nitrogen also fulfills a useful job
and acts as a buffer to control the rate of combustion.
The Nitrous Oxide System
A proper nitrous system consists of a high pressure bottle
usually of 10 lbs. or greater, high pressure braided steel nitrous
lines, high pressure solenoid valves to control the flow of fuel
and nitrous, and injection nozzles with adjustable, changeable
orifice sizes or jets. Which brings me to my next point.
There are basically two kinds of nitrous systems, "wet" and
"dry." The big difference between the two is the manner in which
the additional fuel is added to your engine.
The "Wet" System
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nozzle
Plate |
A
"wet" system injects additional fuel externally. As you might
recall the Eclipse in The Fast And The Furious had a
"stand alone fuel management system." That is what is meant by
externally added fuel. A wet system injects both nitrous and
fuel into the intake thru a plate between the throttle body
and the intake manifold or via nozzle[s] before the throttle
body. This allows the nitrous fuel mixture to be distributed
evenly throughout the cylinders.
Although, because of fuel's corrosive properties the seals
around the nitrous solenoid will deteriorate due to exposure,
and will have to be replaced from time to time. I recommend
the NX solenoid, because they generally last longer than the
NOS solenoid. |
The "Dry" System
A "dry" system on the other hand, simply increases
the amount of fuel injected by the stock fuel pump. This is
achieved by simply increasing the in-line fuel pressure.
The only draw backs to this type of system is the
limits of your stock injectors which can handle only so much
pressure. Also, because fuel and nitrous aren't mixed like in a
"wet" system, the nitrous/fuel mixture will not be constant in
each cylinder which may cause certain cylinders to run slightly
lean.
A "dry" system is not without advantages. The
biggest advantage is that it does not require any plumbing for
additional fuel delivery. Generally, I suggest "dry" systems for
beginners, and mild street setups.
System Limits
A system with 400 hp is close to the practical
limits of a Acura/Honda engine. That is for highly tuned engines!
For normal mild street setups on a stock engine you really should
not "juice" more than 50% of your stock engine's hp or a 75 shot,
whichever comes firs.
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