Gentelmen, 12SecUv has a good base NOS tune with timing/fuel/KR Timing/Torque managment all adjusted for NOS, Most SHOPs will not do NOS Email tunes because of 2 many variables.. We do our tunes and put them in the safe zone and let the customer fine tune them in. That is the good thing about the Predator is has end user adjustablilty..For example: I can put the same tune into 2 different vehicle of the same model year and mods list which are runnning NOS and I will see 2 differnet results(By the way other customers starting with the same base tune have put there jeeps in the mid 11's with NOS),,most of the time it comes down to fuel quaility and NOS jetting and or bottle pressure being the variable and the end user knowledge of optimizing his vehicle for NOS useage.And again if you are going to spray and dial your vehicle in get a WIDE BAND O2 installed in your vehicle or get it adjusted by a dyno shop to put your A/F in the optimized range for your vehicle...Hope this helps.Just a Note FYI (Fuel quaility and the way fuel companies our blending fuels are just going to more of an issue as time goes on). David
Id double check your pressure gauge. Im not sure how hot it is where you are, but Ive only had my bottle get 900 psi unassisted once and that was in Georgia in August, lol. I agree with Erik and the ZEX bottle heater, it sucks the big one Get a heater that has a pressure switch. Kicks on and off to maintain a predetermined PSI. When all else fails, go NANO
BTW: Bottle pressure is directly proportional to bottle temperature. If you bottle always reads at least 900 PSI, your guage is wrong. See the following pressure chart: Bottle Temp Bottle Pressure 50 degrees 565 psi 60 degrees 655 psi 70 degrees 735 psi (riding around in your air conditioned vehicle with no bottle heater) 80 degrees 840 psi 90 degrees 945 psi 98 degrees 1040 psi See full chart here: http://www.pdqmotorsports.com/page/page/3447777.htm So you can see, unless your bottle is riding around at about 86 dgrees, you don't have 900 psi. And you need that bottle heated to about 92 degrees to maximize its effectiveness. That's also why it takes forever to get the pressure up when running on a cold fall or spring day. SIDE NOTE WARNING: You've all heard stories about how hot it can get in a sealed up car parked out on a hot sunny day, right? Well - the danger of bursting the safety disk and losing all of your nitrous just by leaving the bottle in the car unattended on a hot day is very real. This particular chart doesn't go that high, but it's pretty plausible that in-car temps can be hot enough to burst the safety disk. EDIT: Here's another interesting article: http://www.dragstuff.com/techarticles/bottle-heaters.html
Good info Matt, pumping 17lbs into a 10lb bottle will also increase the odds of pooping the disk too:whistle: I do have to correct something here, a 98 degree bottle with 5#s of Nitrous is going to have a different pressure than a 98 degree bottle with 10#s of Nitrous, bottle size will also throw things off a bit. Im able to pump as much as 23# of Nitrous into my 10# bottle but I need to use it fast because with frost on the bottle, my pressure is right at 1100psi on a 75 degree day. I personally run a power invertor with a heating blacket on my bottle and just monitor my bottle pressure, call it getto but it works and my invertor draws less amps than a NOS blanket.
How is this? (I'm assuming that the lbs of nitrous is weight and not pressure) Liquid nitrous will vaporize/boil at a certain pressure and temperature. Let's assume a fixed temperature (98*). Let's assume the bottle is not completely full of liquid nitrous (15lb bottle). So it shouldn't matter if there is 5lbs of liquid nitrous in the bottle or 10lbs of liquid nitrous in the bottle. At 98* the vapor pressure in the bottle would be the same right? As long as there is any liquid nitrous in the bottle, below a certain pressure it will vaporize/boil, above that same pressure it will condense/turn into a liquid. ...i think...?
This information is completely incorrect. Among other things, 23 pounds of nitrous, even in pure liquid form, will not physicall fit into a 10 pound nitrous bottle. Perhaps your nitrous filling vendor is feeding you some BS and overcharging? And for you physics/chemistry buffs, the equation is PV=nRT (see below) 100% correct. The partial pressure of N2O is what detemines the Pressure/Temperature relationship. The only time the chart would be off, is when the bottle ends up with a bunch of air in it instead of N2O.
My filler/vendor is overcharging me because I have a huge bottle at home and fill my own bottle. I also know for fact that 23 lbs will fit into a 10# bottle because I have done that too. As I said with my bottle having been in the freezer overnight and donor bottle in garage at 75 degrees, I have stopped filling my bottle at 23#s with a pressure of 1100psi with frost on the outside of the 10lb bottle. I found that filling to 17lbs is best because I can control pressure better(less purge) and I can get 6 full 1/4 mile passes. Im not a physics guy, Im a hands on worker who always listens to engineers say in therory is should work. Sometimes I watch the therories fly out the window:grin:sometimes I do find a problem in the system. My 5th grade education leads me to believe that the reason pressure will change is due to room in the bottle. Less room for liquid to expand into gas means more pressure, right ?
Isnt that what I said when I tried correcting you :stars: If it didnt come across that way that is what I meant to say, perhaps I should have gone to the sixth grade :huglove:
Abdolutely not. Unless your bottle is stored below -172 degrees, N2O boils off to the gaseous state until the pressure equalizes. The pressure/temperature relationship is fixed. 92 degrees equals 950 PSI. Each gallon of liquid nitrous weighs 5.44 pounds. I don't believe a 10 pound bottle can physically hold over 4 gallons of liquid. But maybe it can. Looks can be deceiving.
Perhaps. But unless your N2O vendor is screwing you, your bottle will have the same amount of air in it regardless of how much nitrous is in the bottle. a 10 pound bottle with 10 pounds of N2O in it should have exactly the same amount of air as a 10 pound bottle with 5 pounds of N2O in it. You start with an "empty" bottle of nitrous, that simply has one bottle full of atmospheric pressure "air" in it. Now you seal it up and start pumping pure N2O into it. The total amount of "air" stays the same (but takes up a smaller, compressed space) as the amount of N2O in the bottle increases. The partial pressure of N2O will yield the same PSI in the bottle at any given temperature no matter how much N2O is in the bottle until you get so low that all of the N2O is gas and there's no liquid left.
No. Same pressure but less gas. As to your 10 lb bottle holding 17 lbs of nitrous. You could verify that with a bathroom scale. Probably a couple of pounds off but close enough. Weigh the bottle empty. Let's say it weighs 2 lbs. empty. Then put 10 lbs of nitrous in it. Now it should weigh 12 lbs. If you can in fact get 17 lbs of nitrous into your 10 lb bottle then it would weigh 19 lbs. All the above weights are the weight of the liquid nitrous. The trick is the "partial pressure". The partial pressure is the pressure (psi) inside the container when it not completely full of liquid nitrous and not completely empty of liquid nitrous. At some particular temperature the partial pressure will not change. The bottle can be 1/4 liquid and 3/4 gas and it will have a particular pressure. If the bottle was 3/4 liquid and 1/4 gas it will have the exact same pressure inside the bottle. The reason for this is that, at that temperature, more pressure would cause more gas to condense into liquid. less pressure would cause more liquid to vaporize/boil/evaporate into gas. So as long as there is some liquid and some gas in the bottle the pressure will be the same. All the above is at a given temperature. Pretty much the pressure kind of comes from the gas. At least you can visualize it that way. If you raise the temperature then you will raise the "partial pressure". Lower the temperature and you will lower the partial pressure. So what happens if you have a hot fill tank and a cold bottle? The partial pressure in the fill tank will be greater than the partial pressure in the bottle. So what you will end up with is being able to get more liquid into the bottle proportionally than the fill tank. (ok, haven't thought this one through completely but...) Let's say both the fill tank and the bottle are at the same temperature. Let's say the fill tank is 3/4 full of liquid nitrous and 1/4 gas (and the fill tank is MUCH larger than the bottle). If you connect the fill tank to the bottle and open both valves, what you will end up with is a fill tank that is just barely less than 3/4 full of liquid nitrous and a bottle that is just barely less than 3/4 full of liquid nitrous (since the fill tank is so much larger than the bottle you can just say 3/4). Same pressure in both tanks. Same temperature. Now if you make the bottle much colder than the fill tank. The partial pressure will be much lower in the bottle than the fill tank. That means that the gas in the bottle will be exerting less resistance to being compressed and will condense more easily. You'll end up with more liquid and less gas because of the greater pressure from the fill tank. Liquid nitrous is hardly compressible at all. Kind of like water is not very compressible. Once the bottle is basically full of liquid nitrous you're not going to get any more in there without exploding the bottle. When they give the size of a bottle in lbs, that's the weight of the liquid nitrous that will fit in there. You can't fit any more in there than that. So a 10 lb bottle won't hold any more than 10 lbs of nitrous (liquid). Think of a 2 liter pop bottle. You cannot get any more than 2 liters of water in there. 2 liters of water weighs about 2.4 lbs? So you might call a 2 liter pop bottle a 2.4 lb water bottle. you won't get more than 2.4 lbs of water in there. Maybe not such a good example.
Doh. that implies that I guessed wrong on the standard for labeling bottle size. Sounds like they do bottle size (in lbs) at a fixed temp? and it's not just the liquid capacity of the container?
You are 100% correct. In fact, I use this principle to get one full bottle from two partially empty bottles. I heat one bottle up, but the other in the freezer. Eventually, I have a 30 degree bottle and a 100 degree bottle. I connect the two bottles with a short feed line and open them both up. Nitrous is pushed out of the hot bottle and into the cold bottle. The process chills the hot bottle and starts heating the cold bottle. In just moments, the pressure and temperature equalize, but now most of the N2O is in the previously cold bottle.
The capacity is labelled in pounds. The labels state a bottle weight empty, and a bottle weight full. It would be interesting to pour water into a 10 pound bottle without it's valve, and see just how many gallons of liquid it could hold.
I do see what you are saying about the amount of air not changing and agree understand the above statement. For the record and to repeat what I said, Im not getting screwed by nobody, I fill my own bottles. My Donor stays in garage and I usually freeze the bottle that goes into the vehicle for at least 8 hours(overnight). I know for fact how much liquid nitrous goes in because I watch the weight with a scale. The last post I qouted you on really goes with my way of thinking and thats what I was trying to say. Dave I do exactly like you said above cold receiver bottle, warm donor bottle and weigh with a scale. I will agree that perhaps my bathroom scale is off a few lbs. The cold bottle cools the nitrous as it fills, that lowers pressure letting me get more than 10lbs in. I think we are all agree on what Im saying, it just isnt coming across correctly. Lemme try this again and see if my boat holds water. 10# Bottle with 10#s Nitrous at 98 degrees will have 1050PSI 10# Bottle with 17#s Nitrous at 98 degrees will have more than 1050PSI The more nitrous you have to expand(same volume container) into gas the higher your pressure is going be. Do these 3 statements float with you guys ?
Nope. IF a bottle with 10#s Nitrous at 98 degrees has 1050PSI then a 10# Bottle with 17#s Nitrous at 98 degrees will ALSO have 1050PSI As long as there is the tiniest bit of liquid in the bottle (not completely gas) or the tiniest bit of gas in the bottle (not completely liquid) then the pressure will be the SAME at 98*. Doesn't matter if it's mostly liquid or mostly gas (as long as there is some of both) This is the LAW (of physics) and if you violate it you will go to jail (or more likely a parallel universe):magic:
BTLFED, I think I know what you're thinking. Let's say the bottle has half liquid and half gas in it. If you add more liquid then the gas would be compressed into a smaller space and have more pressure? That does happen but almost instantaneously. As the gas gets compressed it does raise the pressure. As SOON as the pressure raises it compresses some of the gas to liquid. Now there is less gas and more liquid. As soon as you squeeze the gas it turns to liquid. You end up with the same pressure.
Ok guys as I stated earlier physics and all its laws are to technical for me. Lemme ask you both this question and in the most simpliest of explainations gimme a answer. Why is it that when I have a donor bottle at 75 degrees in my garage and fill a small bottle that has been in my freezer for over 8 hours, with more than 10#s of Nitrous.(Close or around 23#s) As the bottle temp goes up but is below 98 degrees, I have more than the 1050psi ? Im going out on a limb here but I would guess my bottle temp is below 60 degrees and I have 1100 PSI with the bottle filled to max capacity.
