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Why its jetted @ Solenoids
Why we cant use Oxygen!
V8 into Ford Sierra!
How Nitrous Works:
How Nitrous Works, and how it gives more power. And Why we don't
How Nitrous Oxide Injection
Liquid Nitrous Oxide
along with some additional enrichment fuel is injected into the induction system
"somewhere" along its length. Where exactly that position is,
isn't important, provided that it goes into the engine evenly, with
the same amount of Nitrous Oxide and additional fuel to each
cylinder. That's all that's important here -- that it gets
into the engines intake where it is carried to the combustion chamber.
In some cases
it is even
injected outside the intake system system, aimed towards an
open carburettor mouth or throttle body for example. There
does not seem to be much difference in the performance and
all of the different methods seem to achieve the exact same
There are all kinds of daft arguments about "plate"
(under Carburettor) systems versus Direct port systems and
different kinds of injector or fogger, but in
reality it makes little to no difference at all! The dynamometer has
proved this lots of times over many years. There
are sometimes small differences on different engines but which is best is debatable
and pretty unimportant in the scheme of things..
Once the extra fuel and Nitrous
Oxide gets into the cylinder the heat breaks it down into
Oxygen, and Nitrogen during combustion, allowing
the now newly released free oxygen to burn the
extra fuel. This is where
most but not all
of the extra power comes from.
Notice that with a correctly set
up and running engine there is no additional free oxygen
available until AFTER
correct ignition at whatever timing point the engine is set
up to fire... There is however a greater size of charge in
the cylinder during compression, It consists of a much
denser charge (Due to the charge cooling effect) and the
additional enrichment fuel, along with the engines normal
induction charge of air and fuel. So until ignited by
the spark plug the actual mixture consists of a colder,
overly rich, (the nitrous has not released its oxygen yet)
denser, larger charge. It is for these reasons Nitrous
actually helps prevent detonation in sensible doses of say
30 to 40 percent boost levels.
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.
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 and prevent any detonation.
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 and therefore bhp increase
remains constant no matter what rpm the
engine is at. 100 bhp extra is still 100bhp extra at 1000
rpm, as it is at 6000rpm!
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
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 of combustion 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 real problem to
control. Also compressed Oxygen is in a gaseous form, so
adding oxygen takes up more room in the intake system 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 due to cooling
and contraction and it is adding oxygen and
Nitrogen at the same time. 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. And it can
be stored as a liquid in pressurised tanks where Oxygen cannot.
See more detail
Why we cant use Oxygen!
the term NOS is incorrect as this refers to an specific
company (called Nitrous Oxide Systems, in the US)