Nitrous for my 2006 STI?
10-20-2005, 09:47 PM
#6
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Join Date: Nov 2004
Location: Moved to Portland, OR
Posts: 376
Car Info: 2005 Black WRX STI
Here is my $.20 on NOS on your TURBO Suby.
Yes, I capitalized turbo for a reason. NOS is nitrous oxide, it is a molecule that has 2 Nitrogen atoms and 1 oxygen, the molecule looks like water with the hydrogen atoms replaced by nitrogen atoms. Nitrogen is a resonably inert"ish" element (it doesn't participate in a combustion reaction, at liest in normal engine conditions) but it can disassociate from its oxygen atom quite easily, allowing oxygen to participate in a combustion reaction.
Ok, enough with the chemistry lesson. What does NOS do when you inject it with your fuel charge and air charge? It gives the combusiton reaction more oxygen, the fuel (which is normally is great abundance in a naturaly aspirated engine) has more oxygen to react with, more fuel is burned, bigger explosion, more power.
What does a turbo do? A turbo compresses air (20.8% Oxygen, 79% Nitrogen and little tiny bits of other stuff) and shoves it into the engine. When you compress air from 1 atmosphere (14.7 psi or 1bar) to 2 atmospheres (28.7 psi or 2 bars) you have doubled the amount of oxygen you shove into the engine and can now double the amount of fuel you can shove into your engine, twice as many reactants = twice as big of an explosion. By the way, the pressures above are absolute pressures, 2 bar absolute is equal to 1 bar on your tubo gauge (a stock USDM STI).
Your turbo does the same thing that NOS does! You don't need NOS! If you want more power, shove more air into the engine (more boost, biger turbo, etc). NOS is great for natually aspirated engines because they don't have the freedome of boost.
How can NOS help you? Very carefully, use a small burst of NOS (30 to 50 wet shot) between idle and full spool up of your turbo (On my FP Red this is 3700 rpm). If your running 1/4 mile drags this will help, if your not a 1/4 mile pro - don't even think about NOS.
Yes, I capitalized turbo for a reason. NOS is nitrous oxide, it is a molecule that has 2 Nitrogen atoms and 1 oxygen, the molecule looks like water with the hydrogen atoms replaced by nitrogen atoms. Nitrogen is a resonably inert"ish" element (it doesn't participate in a combustion reaction, at liest in normal engine conditions) but it can disassociate from its oxygen atom quite easily, allowing oxygen to participate in a combustion reaction.
Ok, enough with the chemistry lesson. What does NOS do when you inject it with your fuel charge and air charge? It gives the combusiton reaction more oxygen, the fuel (which is normally is great abundance in a naturaly aspirated engine) has more oxygen to react with, more fuel is burned, bigger explosion, more power.
What does a turbo do? A turbo compresses air (20.8% Oxygen, 79% Nitrogen and little tiny bits of other stuff) and shoves it into the engine. When you compress air from 1 atmosphere (14.7 psi or 1bar) to 2 atmospheres (28.7 psi or 2 bars) you have doubled the amount of oxygen you shove into the engine and can now double the amount of fuel you can shove into your engine, twice as many reactants = twice as big of an explosion. By the way, the pressures above are absolute pressures, 2 bar absolute is equal to 1 bar on your tubo gauge (a stock USDM STI).
Your turbo does the same thing that NOS does! You don't need NOS! If you want more power, shove more air into the engine (more boost, biger turbo, etc). NOS is great for natually aspirated engines because they don't have the freedome of boost.
How can NOS help you? Very carefully, use a small burst of NOS (30 to 50 wet shot) between idle and full spool up of your turbo (On my FP Red this is 3700 rpm). If your running 1/4 mile drags this will help, if your not a 1/4 mile pro - don't even think about NOS.
10-21-2005, 10:04 AM
#9
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Join Date: Jan 2005
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Car Info: 05 STi
Yeah, I too say stay away from the NAAWWWSS!!! Go for bigger boost as you can tune more easily for constant big boost than boost + nitrous oxide. Oh and you forgot to mention, the nitrogen also bonds with the hydrogen molecules in the fuel there by creating another combustable. It does decrease inlet air temps also which is a big help in spool up.
10-21-2005, 10:06 PM
#11
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Join Date: Nov 2004
Location: Moved to Portland, OR
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Car Info: 2005 Black WRX STI
Originally Posted by 1reguL8NSTi
Yeah, I too say stay away from the NAAWWWSS!!! Go for bigger boost as you can tune more easily for constant big boost than boost + nitrous oxide. Oh and you forgot to mention, the nitrogen also bonds with the hydrogen molecules in the fuel there by creating another combustible. It does decrease inlet air temps also which is a big help in spool up.
I agree with everything except...
"Oh and you forgot to mention, the nitrogen also bonds with the hydrogen molecules in the fuel there by creating another combustible. "
I don't understand how this is possible.
Oxygen (by itself) is a negative ion, which is why you only see oxygen with other atoms which balance the molecule. in-fact its a powerful negative ion with a charge of 2-.
Hydrogen is a positive ion (1+). Two hydrogen ions bind with one oxygen (2-) + (1+) + (1+) = 0 charge. The molecule is called H20 or water.
Nitrogen (while bigger) is also a (1+) charge, exactly the same charge as hydrogen and creates a very similar but less stable molecule (N2O) or NOS. I say less stable because it takes very little relative energy to disassociate. The actual size of the nitrogen atoms creates a situation where they are repelling each other (because of their close vicinity around the oxygen atom) are aid in the disassociation energy.
It is physically impossible for Nitrogen (N)+ to bond with hydrogen (H)+ to create another combustible. It would be like trying to take the positive side of two magnets and trying to push them together and make them stay.
Other than that, here is the combustion chemistry for NOS in a engine. This is FYI only.
When heated sufficiently, however, N2O decomposes exothermically to N2 and O2.
2(N2O)g ------> 2 (N2)g + (O2)g
If this reaction occurs in the combustion chamber of an automobile, 3 moles of gas would be produced from 2 moles, providing an extra boost to the piston, as well as liberating more heat. It also has a number of other benefits. The increased oxygen provides more efficient combustion of fuel, the nitrogen buffers the increased cylinder pressure controlling the combustion, and the latent heat of vaporisation of the N2O reduces the intake temperature. Therefore N2O is injected into the fuel lines of cars to give more power to the engine and to give the car more hp.