white2001s10

iTrader: (4)

Results as promised.
ref :https://ls1tech.com/forums/nitrous-oxide/421336-nitrous-pressure-discussion.html

I didn't feel that I could run an accurate test to determine mass leaving the bottle over a given time at given pressure, so I skipped the weighing.
What I did do was get temperature data via thermocouple in a flow tube, and some visual results that I didn't expect.
A 15 lb bottle was used (thanks Homeslice)
NOS cheater solenoid with NOS nozzle and NOS flare jet .047
The test interval was 3 seconds
The thermocouple test lead was 6" away from the discharge of the nozzle

The first test run did not turn out well because the pressure was too low to eject a significant amount of liquid nitrous far enough to reach the t-couple test lead.

Test 1
Start pressure: 1050 psi
Pressure drop from solenoid opening: 50 psi
End pressure: 950 psi
Ambient air in flow tube: 45*F
Stable reading during test: -47*F

Test 2
Start pressure: 1300 psi
Pressure drop from solenoid opening: 50 psi
End pressure: 1300 psi
Ambient air in flow tube: 45*F
Stable reading during test: -107*F

Test 3
Start pressure: 1700 psi
Pressure drop from solenoid opening: 50 psi
End pressure: 1600 psi
Ambient air in flow tube: 47*F
Stable readin during test: -109*F

Test 3 showed a 4*F drop in temp over test 2 which is not significant at all in itself, but suggest that the nitrous is staying liquid for longer after ejection with more state-change happening further away from the discharge nozzle.

What is most significant I think is the visual observation of test 3. The pressure was so high in the flow-tube that liquid nitrous began escaping from the slit in the tube where the t-couple lead was placed. The nitrous grew to about an inch in christmas-tree shape as the area around the slit frosted up. Also the discharge end of the flow-tube (12" away from the nozzle) also frosted up along with the wood base that the tube was secured on.
The difference in test 2 and test 3 was quite dramatic as Homeslice can vouch for. Even if no more nitrous was entering the flow-tube (and we think there was more), it was very obviously soaking up more heat energy during the discharge.

Our conclusion:
Even though the maximum temperature drop in the test area does not drop significantly with the higher pressure, the total area affected by the temperature drop increases dramatically.
For instance at low pressure the nitrous may drop 150*F of heat energy in only 50 cubic inches of air volume,
where at higher pressure the nitrous may drop 150*F for 100 cubic inches of air volume.
To actually quantify this process would take more tests (maybe later on).

Another observed difference is that by behavior of the line and the needle on the gauge jerking during initial activation, the nitrous seems to be moving through the line faster, or at least accelerating quicker at first activation with the higher pressure.

We would have to waste at least 2 full 10 lb bottles to do a reliable test on mass of nitrous leaving the bottle at different test pressures.
We're not ready for that one yet.

Robert56

iTrader: (2)

I haven't had a chance to digest all the info yet, but wanted to be the first to say, your the man.
Robert

Edit, know I know for certain, why I run better times at 1150psi compared to 950psi. This also is a good thing for using IAT vs fuel adder in hp tuner. We are going to master the two tunes in one for the dry hits, for certain. With this info, we can make sure the temps seen on the spray will not over lap with n/a temps, ever. Good job.

JoeyGC5

iTrader: (24)

nice reading material, thanks

cantdrv65

iTrader: (3)

White, there is NO DOUBT the flow rate increases as the you increase bottle pressure. This is consistent with the laws of physics. You can reach a max velocity of the fluid through an orfice at Mach 1, but the flow will still increase with supply pressure. This is often used in industry because at Mach 1 through an orfice the only thing controlling the amount of flow through the system is supply pressure. The pressure on the lower side of the orfice no longer matters.

As you increase pressure, the pressure drop across the nozzle also increases thus absorbing more heat as you described. NIce results! The increase of heat absorbance because of the higher differential drop across the orfice should lead to an increase in power. It remains to be seen whether at this higher flow rate, you are actually increasing the MASS flow rate of N2O... It could be calcluated, and honestly Ive done these types of calculations before in school, but now we have computer programs or vendors who provide. Honestly it may take me days and even then it may have serious errors. I wouldnt be suprised though if you are flowing more mass also. Nice work! Tests done correctly dont lie. Thumbs up!

white2001s10

iTrader: (4)

Thank you, and I agree.

If you follow the link posted to the previous pressure discussion it was claimed that nitrous flow dropped at the higher pressure due to a density change of the N2O going supercritical. It was also suggested that someone who makes more power with the higher pressure is doing so because of the resultant "rich" condition created when N2O flow dropped.

I didn't think that these ideas sounded right. They also seemed to conflict with test results I've seen in the past, so I thought some testing was in order to confirm that I hadn't been halucinating all that time.

NXRICKY

iTrader: (1)

NIce testing one temp drop... We need to get you a scale and do the test burn for a little more time maybe 5 or 10 seconds... What we could be seeing is the high pressure is doing nothing more than moving more gaseous nitrous thus a cooler results at the end... Data is great... Let me know I might have a digital scale I can send to you to do a weight versus temp drop...
Still a little in conclusive as to the volume getting into the engine, it is defenitly colder by your testing...
let me know if you want a loaner scale... I will try to track one down....

Ricky

white2001s10

iTrader: (4)

Thanks, that's quite generous!
I do have my own digital gram scale that will handle the bottles no problem, but Homeslice and I were just short on having two identical full bottles to run a test like that.
I don't think using our 3 second blast time would be nearly enough to be reliable for the amount of weight out of the bottle. If I'm off by just 3 tenths of a second with the activation button then the results would be off by 10% and I wouldn't call that reliable. I'd have to go for at least 10 seconds, but then the bottle would be very drained at that point and be unusable for the next test... thus requiring two identical full bottles.
I have two identical 5 pounders, but neither is full and one needs certified again. I'd prefer two 10 pounders for a more consistant test since the pressure wouldn't drop so fast, so maybe I can borrow one, but I don't see it happening soon with the holidays and nasty weather.
I'm going to keep it in mind though.

I may also increase the length of the flow tube and use multiple t-couples to get a better idea on the quantity of temp drop next time.

Thanks again for the offer.

badass 2002 z28

iTrader: (5)

nice work

Homeslice (tm)

One thing that we did notice during the testing is that there is no way that gaseous N2O is comming out of the nozzle... the nitrous not only left the nozzle as a liquid but remained liquid for at least 4-5 inches within the test environment. There was SIGNIFICANT pressure increase within the test environment as evidenced by the blowout around the thermocouple connection and the exceptionally low temperature. On average we dropped 152 degrees from ambient! You will also notice that even though the test environment was open and passing ambient air and the thermocouple was a significant distance from the nozzle it still recorded 86% of the boiling point of liquid nitrous 6 inches from the nozzle! And that was AFTER mixing with ambient.

Although there was no weight measurement to calculate the volume of nitrous expelled, there is no doubt in my mind as to the VAST difference in the low pressure and higher pressure shots. The 1700 PSI test was VERY violent and the sound, and the reaction of the test environment indicated that things were not the same in there...

Additional tests are nessesary probably with higher pressures and an accurate scale to do volume measurements. If nothing else it was an excuse to go into the garage and get all giggly.

white2001s10

iTrader: (4)

Giggly ? I get a little nervous when the pressure goes up around 2000.
I'll probably go higher next time being that 2000 psi worked so well in-car.

I could put the spare engine in the truck, switch it to SD-mode and hit it with a 200 shot with thermocouples in the intake. I already had a t-couple above the throttle blade, but honestly during nitrous runs I didn't feel I had time to watch the t-couple reading and it doesn't have record-mode unfortunatly. I'd need a co-pilot to watch the tcouple and the WBO2 reading... but that's after the spring thaw.
The LM1 WBO2 does have record mode so I can probably post the files after the test.
I'd have to run it SD mode or the MAF will just add more fueling to a dry shot and make it go more on the rich side.

Homeslice, since your AFR was going bottom 10's we should've upped the pressure to about 2000 psi to see what happens. Oh well maybe Kevin will do it.

ITSTOCK

iTrader: (1)

It makes PERFECT sense to me. I didn't know that higher pressure=more power (TO A POINT) was even up for debate?

Instead of running my bottle at 1150, I might just try 1250.

383LQ4SS

iTrader: (33)

But what we are trying to find out is where and how the phase shift affects flow. I think if you go from 1150 to 1250 thats right in the critical area where you may not see any gain (we still dont know conclusively IMO). IOW....you may see a gain in flow from 1050 to 1150 and see a gain from 1350 to 1450 but you may not see any gain or even a slight drop from 1150 to 1250. It may also be above your solinoids operating pressure if its a small powershot type so be careful.

I have another test that will be simple to do Get a dry shot and put a smaller jet in like a 100 shot dry at 1000 psi....and keep upping the pressure all the way to 1500 or so. The MAF is a pretty impressive and accurate piece. I may try this when my car is ready because I have a rescaled MAF and 42 lb injectors. I can make say...380 rwhp on motor...then spray a 100 shot to make 480 total at 1000 psi....then keep upping the pressure. The MAF should report the differences in flow fairly accurately and the HP will also be an indicator as long as A/F is constant as well. I can also service the pressure with nitrogen for a good starting point and the nitrous temp will be the same everytime. Although heating the nitrous to get to the starting pressure will have an effect as well...so maybe do both

That wont give you the entire story though...because larger shots with greater pressure drop may have slightly differing effects since they may cross below the supercritical phase...even on the much higher start pressures. And obviously Im not going to be able to do a 300 pill (@1000psi) run at 1500 psi

Anyways...cool test.

ITSTOCK

iTrader: (1)

My 2 cents (which isn't nearly as educated as all of yours) is extremely simple and already stated (I'm just trying to catch up a little)

We KNOW that N2O is broken down at 565*F, which releases the oxygen. This creates the MAJORITY of the power by consuming more fuel with more oxygen.

We KNOW that N20 turns to gas at a little over 1050psi (I think it's 1069psi) or right around 98*F.

From that, we can conclude that it doesn't matter whether bottle pressure is 1150 or 700psi, N2O will be broken down when it reaches the engine, or at it's 565* peak break down (I don't know scientific points, so bare with me), resulting in more oxygen in the engine.

HOWEVER, with pressure, comes a change of temperature. When released from the bottle, the nitrous cools to minus 127*F. This provides the cooling charge.

With all that said, I think that the simple answer is that with higher pressure, comes the ability to move more gas per time. It APPEARS to be a DIRECT POSITIVE CORRELATION


http://www.holtzmaneng.com/

860 Performance

iTrader: (1)

Want a loaner time delay realy? You can set it to what ever time you want and its dead accurate and repeatable.
Let me know.
Vinny

NitrousDirect

iTrader: (1)

Great information and testing guys, I love seeing people get involved and instead of guessing getting hard data! Let me know if you need anything from us

ITSTOCK

iTrader: (1)

Here is a quote from the link I already posted....

HOPE that helps a little!

383LQ4SS

iTrader: (33)

Thanks for the input. But what we are looking for is how the phase change at 1150 or 1169 affects flow at and above that point. Some tests have indicated that flow by weight over time actually decreases right above ~1050 psi due to the phase shift and resulting drop in density. Which I blelieve to be true. But I also think flow will pick back up and exceed the "1050 and lower" flow rate at some point if you keep increasing pressure. This may take 1300 psi...it may take 1400 psi...who knows. Thats what we are trying to find out.


Thanks for the chart. That is enlightening in itself. Notice how the flow increases begin to decline in comparison to pressure increases. I wonder if thats due to the rising temp dropping the density of the liquid nitrous...or maybe the additional pressure causing internal friction and resistance to flow. I would love to repeat that test with my nitrogen push and keep the temp at ambiant and see if those two lines would match closer or not.

Robert56

iTrader: (2)

I will be getting a fill station soon, maybe I'll burn up a few bottles for test purposes. This is very interesting, and I would like to know when this phase shift happens. I also, believe it be somewhere in the 1050psi/1100psi area, but we need hard data to be certain.
Robert