the relationship between temperature, pressure, and volume are linear. The charts may be based on different manufactures bottle volumes or the amounts they are filled.

Keep in mind that in order for a temp to equal the same pressure on multiple bottles, that you have to have bottles with the same internal volume filled to the same level or at least have the bottles filled to the same level relative to each bottles volume.

 

WRONG.....A bottle with 4# will have the same pressure as a bottle with 10# if both bottles are the same temp. Although pressure drop will be much greater on the 4# when spraying.

Bottle Temp (F) in Relation to Bottle Pressure (Psi)

10.857 lbs. of pressure per 1 degree of Fahrenheit is required to compress nitrous in a liquid form. This is why the chart below will not show temperature and pressure relationship in even numbers. Example: every 10 degrees does not equal an even 100 psi. increase or decrease.

Note: Since atmospheric air pressure is constantly changing, the numbers below are approximations. A pressure gauge will give more accurate readings.
Bottle Temp(left) vs. Bottle Pressure(right)

-30 / 67
-20 / 203
-10 / 240
0 / 283
10 / 335
20 / 387
32 / 460
40 / 520
50 / 590
60 / 675
70 / 760
80 / 865
97 / 1069

 

OK, I will contact every Physics teacher on the face of the earth and tell them that someone has changed the Ideal gas law.

 

That's the same pressure/temp chart I've seen everywhere, in fact almost word for word. Does anyone know where it originated at or if it's accurate? Anyone ever heat soaked a bottle to 97 degrees and measured the pressure on a certified test guage and get 1069 psi?

I have to disagree about the temperature / psi relationship, it certainly doesn't appear to be linear in the testing I've been doing, nor do the charts you see show a linear relationship.

 

It may have to do with the fact that most calcuations are performed in metric units and the relationship of degrees F to Degrees C is not linear, Physics was a long time ago but the temp/pressure/volume part was pretty straight forward.

 

Below should get you close....

paste this into Excel and make C1 bottle temp in F deg.
It will return pressure at that temp.
= 4.93699197920628*10^-11*C1^6 + 7.8446262319939*10^-9*C1^5 - 2.71170387182592*10^-7*C1^4 - 1.13742299816776*10^-5*C1^3 + 0.02726079416429*C1^2 + 4.78372764455909*C1 + 285.215925321968

paste this into Excel and make F1 bottle pressure in psi.
It will return temp at that pressure.
=-5.09260745586214*10^-16*F1^6 + 2.74286977371321*10^-12*F1^5 -5.74199864378633*10^-9*F1^4 + 5.91997085061595*10^-6*F1^3 - 3.20502663067251*10^-3*F1^2 + 1.01778189511439*F1 - 131.758386456124

 

what language is that??i should have went to college.LOL

 

The problem with temp. is where do you take the temp from? If you heat the outside of the bottle it will take time to change the temp of the liquid inside.

Without total control over the Temp. inside and outside of the bottle the pressure will change depending volume of liquid and volume of gas inside the bottle. A full bottle will lose pressure quicker down track than a bottle that is 3# from full due to the volume of gas when you start your run.

I'm not sure what the math looks like but it is all physics.

 

Thanks Elowe65 (Eric?), that looks closer than the other charts. Output from those calculations generates:

Degrees PSI
70 762.235
71 771.798
72 781.488
73 791.309
74 801.265
75 811.361
76 821.602
77 831.991
78 842.533
79 853.235
80 864.100
81 875.134
82 886.344
83 897.733
84 909.310
85 921.078
86 933.046
87 945.219
88 957.605
89 970.209
90 983.039
91 996.104
92 1009.409
93 1022.963
94 1036.775
95 1050.851
96 1065.202
97 1079.835
98 1094.760
99 1109.985
100 1125.522
101 1141.378
102 1157.564
103 1174.091
104 1190.969
105 1208.209​

Assuming these are accurate, it appears my "good" guage or my temperature measurements range from 10 to 30 psi off, or there is some other factor affecting my measurements.

 

thanks Elowe65 for posting up the formula

Anyone have a formula for nitrous flow based on bottle pressure thru a specified jet?
BP is 900, Nitrous jet size is 73, equals X lbs/second ?

 

Yes... both fuel or nitrous...

Not something to pass out as you should flow the system to be sure as too many variables can change....

900psi, .073jet = ~641.66lb/hr = ~.178lbs/sec

Also, Dave's program will give you that (Nitrous Master)

 

its called bullshit

 

its call pressure/density data taken from Matheson data sheet.

 

Round here , we aint that smart . We just build a fire or chill the jug till one of them there red light guns says that it's 90*
Dont much madder what them little round things say , do it ? Whut really madders is that ya.........
Turn one yeller light on , make it spit out all the air right to the mouth of that lil round thing , turn the second yeller light on , mash the button on the wheel , then mash the pedal all the way to the floor , and hold it there no madder how wet yur drawrs git , look fer a big yeller light and flick the button ya been holdin down on the wheel ......The rest is just a blurrrrrrr.......Is I missin sumpin else .....?

246 Charlie Cullotto, Palm City FL, TubeCarz-Olds 6.601 198.79 198.79 .......

 

Round here , we aint that smart . We just build a fire or chill the jug till one of them there red light guns says that it's 90* Dont much madder what them little round things say , do it ?

Smart enough to not trust them little POS gauges, but not smart enough to look at pressure instead temp.....j/k


if temp is important, then why dont every one purge their bottle in the car to the right temp????

morale of the whole thread;

temp is nice to get an idea, but always go by pressure....by use of a high quality gauge...

At least those are my thoughts...

 

if temp is important, then why dont every one purge their bottle in the car to the right temp????

Guess you never checked bottles before and after purge. The temp does in fact go down.

 

So your saying that you purge to a certain temp???

Wow, thats a 1st for me, never heard someone doing that....

I always purge to a certain pressure, regardless of temp.....

 

So your saying that you purge to a certain temp???

I purge to 950 psi with a gauge that is tied to the distribution block on the intake. But when I first got my bottle heater and wasnt paying attention the bottle got up to 96 degrees and I didnt have a spare, and they already called us to the lanes. I gave it a good blast and the temp did go down along with the pressure. Ever have to empty a bottle to change a valve? You can feel the temperature drop as you empty it. How accurate is the gauge? I dont know but if I always have it at 950 its kind of irrelevant what the actual pressure is as long as its always the same.

 

As far as this fizix goes, I have no idea what your talking about and I misplaced my slide rule, but I "TRY" to keep the bottles 88-90 degrees, it only requires a short purge. I also have a Zex bottle heater in the car and run it off another battery that gets removed before a run. It works well.

 

i think this thread has lost focus of what it was created for....

Someone asked for a press vs. temp chart

I believe the question was answered.

Everyone may have their own ways to control it, what is right and wrong is up to each...

 

but look how much fun we had :-kill

 

Hell yeah, this is the Bullet!!!!!

YBBitch:

 

:smt052:butthead:

 

All I was trying to say is , when someone is at the track and wants to know what "pressure " their bottle(s) is/are at . All they have to do is walk past it and and point the light at it , rather than go find a wrench , get a bottle adapter , make sure the gasket is not torn screw the adapter , line , and gauge to the bottle , then move on to the next bottle.... Me I got to go ride around on the golf cart and other important stuff like that than to be fumblin around with useless hardware.....For those who like doing things the hard way ......continue on with the status quo . For those who want to move into the new age , NAPA has a good temp gun for $89.00 bucks .
But dont think I have given up on pressure entirely , there is still a time and a place for it........while in use....!
OldDogWillingToTryNewTricks

 

Here's what I used to heat my bottles to 95° rather than to a set pressure. If you put your bottle at a set temp each time you will end up with the same pressure. The 95° thermostatically controlled transducer will give 1050psi statically. There are a couple benefits going this route over a pressure based transducer, IMO. This transducer simpily goes right under the heater strap, less junk now hanging off the bottle.

Robert

 

PEPI's come with the NOS heating pad. They use two in series with the relay. I guess they figure if one fails (shorted) the other will still be there for safety. If they both short, then you're in trouble if you aren't watching the pressure!

The problem with them is everytime you swap a bottle you have to put the pad on the next bottle and stick the PEPI's in between the pad and the bottle. It's a hassle in my car due to the cage, but it does work.

 

Yes NOS uses them also, however, they are the 85° models so dynamice pressure is a little lower than I like to run and thus using 95° transducers. Mine are stuck to the heater straps with velcro and no problems on changing the bottles out.
Robert

 

Gotta look at the ones we have at the shop. Not sure of their value. They are a pain in the butt to buy though. Always making me buy them in lots of 500 at a time.

I designed them out of all but one product. Suckers are expensive (for what they are).

 

never knew that...