Nitrous Oxide 101

Discussion in 'Forced Induction & Tuning' started by 97WhitePony, Jun 18, 2006.

  1. 97WhitePony

    97WhitePony Active Member

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    Just 2 Nitrous Articles I wrote a while back, figured I would share... Its a long read, but i think its pretty informative...



    What is Nitrous Oxide? Well kids, gather around ole' Uncle Russ and let him tell you a little story about "giggle gas"! Nitrous Oxide is a combo of 2 Nitrogen atoms and 1 Oxygen atom (N2O) this mixture is 36% Oxygen if you were to weigh the molecules. These 3 atoms together are locked until they are heated up really fast, and REALLY hot, then, they CRACK apart and some really neat stuff happens. More about that later. Lets start at the basics! Nitrous was actually first used in WW2 by allied aircraft pilots to give them an extra advantage on how fast they could climb and fly! After turbine engines were invented though, the bottles were put to bed until the 1970s! This is when Mike Thermos and Dale Vaznaian came around and re-invented the nitrous oxide kit! In 1978 these two men formed what we now know as Nitrous Oxide Systems (NOS)! (Just a writer's side note. N.O.S. is an abbreviation not a word! If you want to say NOS (NAWZ) then you should stay away from cars.) Enough of that, moving right along!

    We will start at the bottle. Probably the most common bottle used in the world of Nitrous is your basic 10lb bottle. Although nitrous is a gas, when you compress it, it will become a liquid. This happens because the nitrous molecules are forced closer together and move a little slower. This slower movement of molecules gives us our liquid. This liquid cannot be measured in gallons like a gas tank. So we measure it by POUNDS (lbs). So a 10lb Nitrous bottle will hold, well, 10lbs worth of nitrous. This amount is measured at your N20 distributor on a scale called a FREON SCALE. The bottle is pumped full of nitrous as the tech watches the scale closely monitoring how "heavy" the bottle is getting, at 10lbs, the tech cuts off the feed, and you now have a full bottle of "Go Juice". READ ON there�s more!

    Next, off the bottle, we will look at the different lines and valves, called "plumbing". To stop the N2O from exiting the bottle, a manual valve sits there that you can open and close MANUALLY (go figure). This can be substituted with a valve called a "remote bottle opener" (this will be covered in another article) but for now it isn�t important. Just know that when the valve is open, out comes N2O and when its closed, it stays in. The line that will run from the bottle to your engine compartment is high-pressure braided steel line. These lines are sized by a special measurement called AN. AN sizes, originally developed for use by the U.S. Armed forces ("A" for army and "N" for navy), describe the outside diameter (O.D.) of tubing in 1/16-inch increments. For example, an AN 2 fitting will fit a tube with an O.D. of 2/16", or 1/8", while an AN 8 fitting will fit a tube with an O.D. of 8/16", or 1/2". Because the actual thickness of tube walls can vary from brand to brand, the inside diameter of a tube is not used as a reference. You will also find the dash (-) symbol or the word "dash" itself used in conjunction with AN sizes. A "dash six" fitting translates to AN-6. Another type of measurement you will encounter is called NPT (National Pipe Taper). NPT are the most commonly used fitting sizes for general plumbing, piping, and tubing use; not quite as popular as AN for automotive use, but still very common. While AN fittings depend on the outside diameter of a tube for sizing, NPT fittings depend on the interior diameter (I.D.) of the fitting itself.

    Moving right along the main nitrous line, we will hit what is called a Nitrous Solenoid. This is a magnetic valve called a NEEDLE VALVE. That when electricity is passed over it, opens really fast. The speed at which this valve opens is measured in milliseconds (ms). On the OUT side of the solenoid is yet another high-pressure steel line. This line will go into your intake usually through a nozzle or a throttle plate, depending on your application. At this point, the nitrous will either blend with FUEL (for a wet kit) or just get sucked into your intake. More on the wet kit setup in the articles to come.

    As the nitrous enters your intake, it will enter a cylinder (which ever one is on its intake stroke) as it enters into the cylinder, the piston will begin to rise back up towards top dead center. During the combustion process in an engine, at about 572 degrees F, nitrous breaks down and releases the oxygen atom. This extra oxygen that has been released, creates the ability to burn more fuel (the more fuel you can burn, the more HP you can make). The left over nitrogen acts to buffer, or dampen the increased cylinder pressures helping to control the combustion process. Nitrous also has a tremendous "intercooling" effect by reducing intake charge temperatures by 60 to 75deg F!! This is a very good thing!


    Russ Conrad - 97WhitePony :bunny3:
     
  2. 97WhitePony

    97WhitePony Active Member

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    And a little more in depth of the actual systems...


    In my previous article, I discussed the basics of nitrous oxide, what it does when it enters an engine, and basically what happens when the air and fuel mixture ignites with the nitrous. Now, I want to continue this series on the difference between wet kits and dry kits. We have all heard of both kinds, but what does it all mean exactly? I hope one of us can find out after this!

    Dry kits. Dry kits, as they are called, use just a bottle and a nozzle. Probably the most medieval version of this system can be described as having a bottle with a manual valve, a braided steel line, and the other end somewhere on your intake. Crack the valve open, and off you go! Now a days, thankfully, we don't have to resort to such a "ghetto" setup. It's a little easier than that. A dry kit consists of one nitrous bottle, 2 nitrous lines (one from the bottle to the solenoid and one from the solenoid into the engine), one nitrous solenoid, and one switch to activate the solenoid (manual or WOT). We will get to wiring these things up in a future article, but for now we will concentrate on how this plethora of parts works as a unit. As you arm the system and activate the WOT (we will use the WOT switch as an example, since its most common) switch at full throttle, the solenoid will open up and begin to inject raw nitrous. As we learned before, this nitrous will CRACK down and become part oxygen and part nitrogen. This extra oxygen is what allows you to burn more fuel (remember air/fuel ratios), which, in turn, will make more HP. But, unfortunately, with all this oxygen being moved through your motor, you�re going to need more FUEL. Without the proper air/fuel mixture, your motor will do what we call "LEAN OUT". Which basically means you have too much air in your air/fuel mixture. This excess of oxygen causes a massive amount of heat build up, which can cause engine over heating, detonation, or even burnt valves. To solve this, you will need more fuel injected into your motor when you spray. Sometimes you can get away with a smaller shot of N2O (as in a 50 or even possibly a 75 shot) but that is going to be the limits until you bump up your fuel pressure. Unfortunately as you bump up your fuel pressure to make up for your fat nitrous shot, as you run "all motor", you're going to run incredibly rich! A result of you running rich is that you're going to "bog" down your motor with way too much fuel, which is going to make your car run even worse! This is going to be constant battle you will have with a dry kit; trying to get a "stoicheometric" (man I hope I spelled that right!) or perfect air/fuel mixture, but yet staying a hair on the rich side on motor, so that you wont lean out when you spray. The best way to monitor this situation is through a gauge called an Air/Fuel Mixture gauge. This is a MUST for anyone running a power adder! If you don�t want to fool with all of this mess of mixtures, there is always the alternative!

    ON A SIDE NOTE, you can use youre stock O2 censor and an after market A/F gauge, but you wont get a true reading. Stock O2 sensors only read in 1s and 0s (rich or lean). A WIDEBAND O2 reads in better incremints...

    Wet kits. Wet kits, which is called this because not only do you run N2O, but also you piggy back raw FUEL with it. As we learned in the last paragraph, nitrous that is injected into the motor and then cracks, will release OXYGEN into the motor, which can cause a motor to run LEAN. This is a problem a lot of dry kit users face. With a wet kit, however, there is NO worry for this. You don't have to worry as much about leaning out with a wet kit. The selling point on this setup is going to be that you can run extra fuel with it, and only run that extra fuel when you hit the switch! This means you can tune your car to run its best on motor, and then turn around and find a happy medium to run its best on nitrous. This allows you to run the most efficient on either setup (motor or spray). The way a Wet Kit works is; you still have your basic nitrous set up, but off of that you tap into the Schrader valve on your fuel rail and run a braided stainless line to a Fuel Solenoid, which in turn, will run into your Nozzle or Throttle Plate. With this set up, the only thing limiting your amount of spray, is going to be how much HP your motor can handle and, when you start to make big HP, you're going to need to make sure you can provide enough fuel. You can do this by either installing a bigger pump, or installing an INLINE pump. To figure out how much fuel you're going to need, you'll need a formula. HP divided by 2 = lb./hr. (pounds per hour) lb./hr divided by 6 = gallons per hour required (min) Multiply GPH by 1.15 for safety factor. For example: Example: 600 HP divided by 2 = 300, 300 divided by 6 = 50, 50 multiplied by 1.15 = 57.5 (minimum gallons per hour)(This formula is for gasoline only.) Other than that, the sky is the limit. This, in my opinion, is the best bet for anyone who wants to throw on a quick and easy power adder! It costs just a little more, but definitely not as much as a new motor would cost!

    Russ Conrad - 97WhitePony
     
  3. Lightning Struck

    Lightning Struck Legend

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    good write up :)
     
  4. Matt94GT

    Matt94GT Legend SN95 Supporter Retired Staff

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    good write up. thanks!
     
  5. Justin_Bradley

    Justin_Bradley New Member

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    I have a question...

    A guy that 'puts' around here in a second gen (I think) Celica had a 'ghetto dry kit', as you referred to it. His budy would ride in the hatch and open the bottle :)...

    My question is this: He kept referring to the 'Pill' in his kit. Was this the nossle or the solenoid, or something else entirely?
     
  6. DisturbedRacing

    DisturbedRacing New Member

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    "Pill" is a slang for jet. He was referring to the jet in the nozzle.
     
  7. 94gtstang50

    94gtstang50 Well-Known Member

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    thats a long ass thread, i'll have to re-read it when im awake.
     
  8. Slow98GT

    Slow98GT Active Member

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    yeah when i first got on here i read it took me about an hour and a half because i would lose intrest in it
     
  9. Downshift

    Downshift Well-Known Member

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    Great article man, answered quite a few Q's I had. As for the guy riding in the back HHAHAHA wow that is extremely ghetto!
     
  10. 5.0man

    5.0man New Member

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    CORRECTION: Don't take it personeal Russ but alot of people make the same mistake.

    Actually AN flex line is measured by the ID or inside diameter in 1/16 of an inch. Hard line is measured by its OD or outside diameter and wall thickness in 1/16 of an inch. So a 1in. flex line and hard line will not have the same OD. For example you have a 1in. hard line with a .25in. wall thinkness. To find the ID of the hard line you subtract 2x wall thinckness from the OD and you get an ID of 0.5in. Flex line wall thickness is important but you buy it per application. So a You will want a high pressure line for nitrus but a med pressure line for oil supppily for turbo or supercharger.

    Here is the difference between high, med, and low pressure flex line.

    AN size ID Size MAX. allowable pressure(PSI)

    low pressure:
    -2 1/8 600
    -6 3/8 300
    med pressure:
    -2 1/8 3,000
    -6 3/8 2,000
    High pressure:
    -2 1/8 3,000
    -6 3/8 3,000
    Hight pressure line no matter the diameter will have a max psi of 3,000
    mike



    Hope this clears up any confussion.
     
  11. 94gtstang50

    94gtstang50 Well-Known Member

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    Sweet write up. :thumb:
     
  12. Lightning Struck

    Lightning Struck Legend

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    +1
     
  13. 95KBGT

    95KBGT Legend

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    nice i will re read that when im cohearant enough to be reading :bunny3:
     
  14. 95KBGT

    95KBGT Legend

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    im sober and i still dont follow lol
     
  15. 97mustang82

    97mustang82 New Member

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    Nice, I did some nitrous research since i've been wanting to get a nitrous set up (100-125shot) and got some good info from my power & performance teachers at school. I've narrowed it down to the NOS NOSzle 4.6 2v direct port kit. Expensive, but I like that it comes with, wot switch., fuel press. switch, & window switch which i'll endup spending around the same adding those neccesities on to regular fogger kits. Plus no worries of puddling fuel in the intake tube, throttle body, or manifold. Aside from the kit, i'll need to get a bottle warmer, brackets, purge, blowdown tube, and colder plugs.
     
  16. 97blackgt

    97blackgt Well-Known Member

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    whats the dif between all the different types of systems..? suck as fogger, direct port?
     
  17. IMPORTKILLER

    IMPORTKILLER New Member

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    Awesome write up. Thanks for your time and detailed explinations. What is the best kit to go with if you are looking to go 100-125 shot on the 96 4v motor ???
     
  18. voidfinger

    voidfinger Well-Known Member

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    Wet Kit, DynoTune. under 500 dollars. Can't beat it with a big stick
     
  19. NXcoupe

    NXcoupe Well-Known Member

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    Very well written article except for this part. I am sorry, but I have to interject. I race a dry kit and this is not how it works. NOS was the first company to offer a dry nitrous kit for a late model mustang efi. The way it works is very simple. The early fox's and SN95's have a fuel pressure regulator that regulates how much pressure the fuel rail sees. For every one pound of increase in fuel pressure, the injectors flow more fuel for each given pulsewidth. A pulsewidth is a digital wave that goes on, then off for a specific amount of time. In other words, the injector turns on then off, and while it is on, it flows fuel. Say your car has 19 lb injectors, well that is measured at a specific fuel pressure, which is 40 psi for most fords. If you raised it to say, 75 psi, those same injectors will flow fuel comparable to a much larger injector for each given pulse width.
    Now, onto how simple this kit is. Nitrous has pressure, lots of it. The suggested and recommended pressure is between 900 and 1050 depending on the kit manufacturer. So you have that much pressure sitting at your solenoid just waiting to shoot into your engine. Well, what if we could reduce that pressure and then put it onto the fuel pressure regulator? Well factory and most aftermarket regulators are what's called boost sensitive and vacuum sensitive. Vacuum lowering the fuel pressure(hence the line from your intake to the regulator, helps lean out the idle) and boost or pressure to the regulator increases fuel pressure pound for pound. So if your regulator saw 10 psi of pressure coming through the hose to it, it would in turn raise the fuel pressure by 10 pounds. get it? Ok, so what NOS did was make this ingenious little regulator that goes between the two solenoids in the kit. There are two solenoids in line, with a T in between them with the nitrous regulator off the T. When the nitrous is activated, the first solenoid opens, allowing the pressure to hit the closed second solenoid and the T that has the nitrous regulator on it, it steps the pressure down to about 70 to 100 psi and shoots that to your fuel pressure regulator, which raises the fuel pressure up to 70 to 100 psi, depending on the limits of your fuel system. This in turn allows a pressure switch in the fuel line, also provided in the kit, to close, and send electricity to the second solenoid that then opens and allows the nitrous to flow into the intake. What an ingenious system huh? The system won't activate until it 'sees' the fuel pressure spike up, so the engine is already starting to richen up when the nitrous arrives.
    Well, how do you tune such a thing? Well, the vacuum line that goes from your intake to your fuel pressure regulator gets a T in it. Two of the legs of the T are just a straight through from the nitrous pressure regulator to the FPR, fuel pressure regulator, the other leg has a nitrous jet in it, to bleed off the pressure into the vacuum line going to the intake, so you can tune the nitrous shot, if it is too rich, then put a larger 'bleed' jet as it is called in and it will bleed more nitrous pressure off and lower the fuel pressure in the rails. Very cool huh? The opposite is also true, want more fuel to richen the mixture, then put in a smaller bleed jet. It works very well and doesn't put fuel into an intake designed to move air only. Fogger kits and Nozzle kits do a similar thing, but inject fuel and nitrous together at the entrance to the cylinder head intake port.
    Now, are there other ways to do a dry kit? Yep. One of the ways is a ghetto style kit. Compucar used to make it, the bottle in a bag kit. It was very simple and kind of dangerous, but cheap so they sold a lot. The nitrous system only has one solenoid, and it passed nitrous into a nozzle that was in front of your mass air meter, and you had to 'aim' it at the sensor, so the MAF sensor would see the cold nitrous and the increased flow as the nitrous slams into the meter. This tells the computer that more air is coming in and it is very cold too, so it richens up the mixture, hopefully, and down the track you go. They only went up to 125 for a shot, but I know quite a few people that have shattered intakes and burnt plugs from these kits.
    Another way to run a dry kit, is with a specific tune or system. I use a PMS and without disclosing all my race secrets here, I will shed a little light on it. the PMS is a programmable management system for the eec series of ECU's. It allows you to change many functions such as a/f ratio, injector size, timing, idle, etc. Kind of like a chip or a programmer, but in a package that is user programmable. One of the features that I utilize is the Nitrous tables. When the nitrous solenoid is activated, it takes 12 volts to turn it on, so you put a wire on that power wire going to the solenoid and send it back to the PMS and attach it to the nitrous wire provided with the unit. When 12 volts goes to the solenoid, the PMS sees that 12 volts and 'knows' the nitrous is on and active. You can then go into the nitrous tables and pull out timing and add fuel. this makes it a dry kit, and the injectors are told to open their pulse width longer by whatever value you put in. I have spent several years getting my car to function at a level competitive in the class I run in. It won't take you but a few hours on a dyno to get it dialed in and go have fun with it. This system also requires larger injectors because you are not increasing fuel pressure. So to allow the injector to be able to flow the amount of fuel required, you need a larger injector. There is a rule of thumb for that, but if you want to know, just PM me or post up.
    I hope this clarifies that and I didn't mean to step on anyone's toes. I just wanted to get the knowledge out there so people can make an informed decision. I run a lot of nitrous along with a supercharged car too. Been racing nitrous cars since 1998 and my cars have been in various magazines and websites. I am a big fan of nitrous so anyone that has any questions about it are welcome to PM me or just post up on the board.
     
  20. got5.0

    got5.0 Well-Known Member

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    agreed... I was also wondering... it Said I could buy a fogger in the nitto legends game lol and I was wondering what it was compared to other things... what are the other things?? thanks.