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Burgerman's
Build your own DIY Nitrous Oxide
(N2O)
Kit - How it works!
www.nitrous.info
Web design & contents,
Nitrous / fuel Jet Sizing, technical information, pictures, charts are all
© John C Williamson 1987/2003
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Privacy Policy |
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HOW NITROUS OXIDE INJECTION WORKS...
Nitrous Oxide and
additional enrichment fuel is injected into the induction system
somewhere along its length. Where is really not that
important, provided that it goes into the engine evenly, with
the same amount of Nitrous Oxide and additional fuel to each
cylinder.
There are all kinds of daft arguments about "plate"
(under Carburettor) systems versus Direct port systems, but in
reality it makes little to no difference at all! At
least when using Nitrous Systems jetted at the solenoids as
my systems & HighPower's and Akamoto's systems are. The dynamometer has
proved this lots of times over many years.
Once the extra fuel and
Nitrous Oxide gets into the cylinder it the heat breaks it down into
Oxygen, and Nitrogen, under compression & combustion, allowing
the now free oxygen to burn the extra fuel. This is where
most but not all
of the extra power comes from.
Nozzles or Injectors
Known as "Foggers" (started by NOS Systems in the US), These
inject the Nitrous and use this rapidly expanding liquid
Nitrous as it starts to boil off into a gas to atomise or "fog" the fuel as it enters the inlet
tract. The high pressure Nitrous Oxide hits the fuel as
it enters the intake, and breaks the fuel into a very fine mist. The point of injection can be very close to
the cylinder for minimal expansion, or at the throttle plate
or elsewhere in the induction system. In many cases, depending
on how the nozzles are situated and aimed, the normally
aspirated airflow will normally increase as well - in part due
to the cooling effect increasing the density of all the
air/nitrous inside the inlet tract.
Cooling Effects
Cooler intake air is denser and contain more oxygen atoms per
cubic foot. So cooler air will allow more fuel to be burned
and in turn make more power. A 10 degree drop in temperature
can add 1 to 1.5% power to an engine. Nitrous oxide boils at
-129°F and it will begin to boil as soon as it is injected.
This can cause a 80° or so drop in manifold air temperature.
Now if we are dealing with say a 400 hp engine, we can see
well over 30 hp gained from the cooling effect alone. This
cooling effect also helps the engine deal with detonation.
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Average Power
If you were to build a 550 hp 350 Chevy, it would have to rev
to 7000+ rpm to make that kind of power and only make power in
a narrow rpm range. A nitrous injected 350 Chevy making 550 hp
would make that power at a much lower rpm and higher average
horsepower. So the nitrous engine will out perform the
normally aspirated engine by a healthy margin. The reason is
that nitrous flow remains constant no matter what rpm the
engine is at. At lower speeds there is more time for the
nitrous to fill the cylinders, so you get more nitrous in
the cylinders per power stroke at lower rpm. This will boost
power more at low rpm (before the engine is in it's power
band). As rpm increases, and gets in the power band of the
engine, you will get less nitrous per power stroke, but the
engine will start making more normally aspirated power. This
really flattens out the torque curve and widens the power
band.
So Why Not Pure Oxygen?
Air has only 21% Oxygen, the rest is made up
largely of inert Nitrogen. That nitrogen does not aid in combustion
at all, but it does absorb energy, expand and carry heat away. When you add
Nitrous, it has 36% oxygen with the rest being Nitrogen once
the heat has broken it down. So
the more Nitrous Oxide you add, the less percentage of
Nitrogen is available to absorb heat. That is why Nitrous
increases engine heat very rapidly. If we were to add pure
oxygen (which has been tried), the percentage of Nitrogen
would fall much faster as more Oxygen was added. We would not
be able to add much Oxygen before heat was a problem to
control. Also compressed Oxygen is in a gaseous form, so
adding oxygen takes up more room and reduces normally
aspirated power, and the amount of Nitrogen from it. By
injecting liquid Nitrous, the normally aspirated power only
drops slightly and in some cases it increases and it is adding oxygen and
Nitrogen. To put it
simply, with nitrous oxide, we can get more Oxygen atoms in
the engine and have a lot more Nitrogen as well. Nitrous can
make much more power before heat is uncontrollable.
*Technically the
term NOS is incorrect as this refers to an specific company
(called Nitrous Oxide Systems, in the US) |
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Web design & contents,
Nitrous / fuel Jet Sizing, technical information, pictures, charts are all
© John C Williamson 1987/2003
|
|