gforcejunkie

1: have a bottle heater. (the bottle should go up to about 850-900. anymore or less and you will run nitrous rich(lean) or the other way and be running fuel rich.)
2: if bracket racing a purge is highly recommended but is not neccesary.
3: i dont suggest changing the jets but you may want to depending on how your engine reacts to the nitrous. or you may want to increase the pressure. to provide a larger shot but dont forget to increase your fuel jet too.
4:if you live in a hot sunny climate have a full bottle blanket to keep the sun and heat off of the bottle.
5: every 50 horse of nitrous should have at least 2 degrees of retard. dont be afraid to take a little extra out. your car may run a little quicker that way.
6: if the bottle is in the cab always have a way for the gas to escape from the vehicle. your burst panel will go at around 3000psi.
7: nitrous shouldnt hurt your car if you take the necessary precautions. this doesnt mean to exceed what your motor can handle.
8: after you get to about 4 lbs in the bottle the pressure in the bottle will decrease faster when used and cause your times to slow down also more importantly will make you run fuel rich. so if you are at the track and down low on the bottle take a tenth or two out. a good way to tell what the pressure is at. is to have a switch mounted up next to the driver for the bottle heater. this way you can turn it off after your pass and stop to see what the pressure is at. if it is down past 750psi i suggest getting a refill or a spare bottle.
9: after your first few passes your car will slow down. depending on the size of the bottle and the amount of shot you use.
10: according to wikipedia the critical pressure of nitrous oxide is 1102.5 psi. at 96 degrees farenheit. im assuming that it varies at different temperatures.
11: nitrous turns into a liquid at 760psi (at room temperature)
if you have any suggestions to add to this post please let me know and i will try to add them asap.

Joe B

1. No offence intended, but It's a "bottle" heater, NOT a blanket heater....a bottle blanket is just that, a blanket for the bottle.....also, many guys (including myself) want their nitrous bottle pressure "over" 850-900, It ALL depends on your jetting. Mine (like many nitrous set-ups) is jetted to run best with 950-1100 PSI bottle pressure(this is VERY common)..............2. A purge is a good idea, but is "completely" optional since usually the only price to pay if you don't run one is that fuel may make it into the engine "slightly" first, which is usually not a big deal at all. if it was such a big deal, EVERY nitrous kit would come with one according to how well you think the manufacturers have it worked out(and none do to my knowledge)..........3. no such thing as "PERFECT CONDITIONS"...A nitrous kits factory jetting recomendations are just meant to be a starting point, and are usually VERY rich, as to "at all costs" avoid a lean condition which could cause detonation and possible instant damage. They also do this because different engines can vary a bit in what they need in jetting, and also for the many guys out there that dont pull timing, change to colder plugs, ECT(it's a safety margin jetting, "error" to the rich side)...........4. A widely known good Idea...........5. also a widely known good idea(depending on jetting)..........6. another widely known good idea is to not let the bottle pressure get too high, but many burst discs are we'll above 1200 PSI, for example: mine are ALL 3000PSI, heck my nitrous gauge goes to 1500 PSI, and has been there many times with no problem.........7.Flat out saying that nitrous WON'T hurt your car as long as you take the necessary precautions, is not always correct(keeping the nitrous to fuel ratio from going lean will be very important with the engine living), but MANY otherwise good running , good condition engines with "properly setup" low HP nitrous kits "can" have something give out simply from the added strain and "massively" increased cylinder pressure that comes along with nitrous use, not to mention the drivetrain problems that commonly occur from the added power and torque(thats just the way it is, and has always been).............8.Just Common sence(depending on bottle size)...........9. Not always true, This ALL depends on bottle size, and the size kit the person is running , Common bottle sizes are 10LB, 15LBS, but even 20LB bottles are out there(i have a couple).....I get "many" quarter mile passes and have ZERO detectable performance loss (in the range you mentioned) with both my 10LB and 15LB bottles since my bottle pressure is kept up all the time...........I understand that your post has good intentions behind it but, as you see, much of it is unaccurate because of other variables involved, and the rest is just generalized info that comes with ANY nitrous kit book..........you should read alot of the past nitrous threads and posts on here, IMO, most every post Iv'e ever read (aside from some real beginers posts) are WAY above this type of "NITROUS FACTS" post

gforcejunkie

thats a huge variance in pressure i would never buy a kit that runs that high. if your pressure varies between 950-1100 psi you wont be very consistent at all. if you do choose to increase your pressure i dont recommend exceeding 1050psi that when the gas will start turning into liquid.

speed_demon24

Higher pressure means more of the nitrous will turn into a liquid, when you compress gas, it becomse a liquid, not the other way around.

rskrause

I run mine at 1000psi, that's how it's set up as far as fuel jetting. If the pressure were higher it would be too lean and lower to rich. What advantage would there be to running it lower??

As stated, the recommendations for jet size with the typical kit are WAY to rich to avoid the bad publicity from blowing up too many motors.

If the parts are of marginal strength for the stress already being put on them, adding nitrous can and does cause people to lose motors. In any case, BIG nitrous shots (250+hp) require a different setup as well as different parts choice to have longevity. And, of course there are parts like trannys, driveshafts, axles, and so on that may also break.

2 degrees retard per 50hp is a reasonable starting point. But what ends up best may be pretty far from that. A dyno is the best place to find out, the track can also be used.

Rich

gforcejunkie

thanks for the correction

gforcejunkie

i dont know if there is a benefit to running lower pressure. it may just be more consistent i know with wilson manifods they chooses 900. there more of the high end nitrous systems and it may just be more consistent times since there is less capabilties for a change in pressure. also a higher pressure may be able to blow out the spark easier.

i wont run anything higher then a 100 shot on a stock internal motor. you can reduce the risk of blowing your motor by taking extra precautions but there is always that possibilty. a 50 horse shot could blow a motor just as a stock motor will blow. you can never tell what happens. some motors are just simply built stronger from the factory then others. i know the ls6 block is not prefered for building a big power plant over the ls1. its just got a little less metal causing it to be weaker.

Joe B

You seem to be confused on my cars intended usage........my current setup is not a bracket car that Im trying to shave off a 100th of a second with amazing consistancy.....this is a regular Slow(compared to what Im used to) High 10 second daily driven street car, and the nitrous kit is jetted to be "near" ideal at 1100PSI... it's also commonly sprayed at 950-1000 when I don't have adaquate time to get the pressure up to the regular 1100PSI (IE: street race )......and, when I do spray with the slightly lower than ideal bottle pressure (for my jetting) it runs just "barely" a hair rich...No big deal at all......but when Im at the track It's always close to 1100PSI where it's jetted to run best.. all clear now........ enough here, don't you have some more "NITROUS FACTS" to think up J/K

srsnow

This is incorrect. While I will not comment on other compounds nitrous at high pressures (over about 1050psi) will exist in a gaseous state.

speed_demon24

I know, I really didn't think that much before I posted that, what I was trying to say is nitrous doesn't majically turn into a gas at a certain pressure. I know my friend was running his kit at over 1500PSI (dry kit).

rskrause

When the bottle is in any state but completely (or very nearly) empty there will be both liquid and gaseous nitrous. If the bottle is not empty and is installed correctly, the siphon tube will terminate in the nitrous liquid. When in use, LIQUID nitrous runs through the lines and out the jet(s) where it immediately vaporizes due to the pressure drop. In the process of vaporizing, it gets very cold (heat of vaporization). The cold nitrous, now in gaseous form, mixes with the air fuel charge and enters the cylinders.

At any pressure there is a tiny amount of nitrous vapor in the tank. It fills the portion of the tank not filled by liquid, but the mass of nitrous in vapor form is very small. The density of the liquid versus the vapor is why you want to flow liquid nitrous to the nozzle. Besides absorbing heat where it does some good (in the intake tract), a much greater mass of nitrous is delivered compared to what would be if it were in a gaseous state.

The pressure of the nitrous is a function of the temperature. The higher the temperature, the higher the pressure. As the pressure increases, the flow rate of nitrous will increase. That is why for a given jet size it's important to keep the bottle temperature consistent. The nitrous:fuel ratio varies with flow. Low temperature = low pressure = low nitrous flow = richer. Higher temperature = higher pressure = higher nitrous flow and a leaner mixture. Within pretty broad limits, bottle temp doesn't matter as long as it's consistent.

A little nitrous 101

Rich

01Z

Then how does the gas nitrous get into a liquid state?

Injuneer

Rich.... the problem I have is the "critical point" of nitrous at 1052psi. Above that pressure, according to the definition of the critical point, the nitrous can exist as both a liquid and a gas. That amorphous state may actually cause flow to NOT increase in direct proportion to the square root of the pressure difference (nitrous pressure - manifold pressure).

The concept of critical point is still little fuzzy to me, and I've asked some genuine ChE's to explain it to this dense ME, but so far no luck.

mrr23

the only time you will have just air is when the line is opened from taking the line off the bottle. the rest of the time, it will be nitrous. what you are doing is bringing liquid nitrous up to the solenoid and expelling the gaseous nitrous. the point where the oxygen seperates from the nitrous is inside the combustion chamber when 's at 575*F.

gforcejunkie

i know a few people who dont get a purge and just loosen the fitting at the solenoid i dont recommend it but it works. but as long as you leave the bottle on there should be no reason to even use the purge. you should only leave the bottle on if doing back to back runs.