NITROUS OXIDE ( nos / n2o ) advice forum
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Nitrous flow
http://nitrous-advice.org/viewtopic.php?f=4&t=7420
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Author:  Noswizard [ Sun Sep 13, 2015 11:10 pm ]
Post subject:  Nitrous flow

This thread is to explain why 99% of US nitrous products cause UNEVEN distribution.

So we'll start with parts like rails, spray bar plates, slab type distribution blocks as sold by the likes of NX & others, all of which have an entry at one end, with exits down the sides that are positioned at rights angles to the entry axis and a blanked end.

To make this easier to understand;
1) Remember nitrous oxide is made up of molecules which have MASS
2) When anything with mass is travelling at speed it has INERTIA, which means it doesn't like to be stopped.
3) Think of nitrous flow as a bus (or train) with doors at the front, packed full of standing people driving down a dead end street.

So the bus packed full of people is charging down the road at 1,000 MPH (psi), so it flies past the first, second, third etc. drop off points before it crashes in to the end of the street, causing all the people to pile forward (due to their MASS being acted on by INERTIA) and break out of the front doors.

In nitrous terms this equates to the nitrous flowing into the tube at 1,000 psi flowing past the exits nearest to the entry and then crashing into the blanked end of the block, spray bar or rail, before flowing out of the exits nearest to the blanked end.

Unlike the bus example which has a limited number of people (molecules), the nitrous keeps feeding molecules into the tube and as a result the nitrous fills the tube and progressively flows from each of the exits, until it's flowing from all of them. However, although there is flow from all the exits, the inertia still affects the flow and as a consequence, most flows from the exit furthest from the entry and least flows from the exit nearest to it, as shown in the diagram below.

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To make matters worse with spray bar plates;
1) They feed the fuel and nitrous from opposite ends and although the nitrous issues aren't quit as applicable to the fuel side, the same effects do still have some effect, which means the cylinders that get most nitrous get least fuel, which is why cylinders nearest the back of the engine are most likely to suffer a meltdown.
2) They add multiple bars/stages and the only thing worse than one spray bar is multiple bars.

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The only thing worse than multiple bars is having the bars at 90 degrees to each other, as that can only screw up the whole distribution deal

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I hate to think how bad the distribution is on this one;

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Putting 2 bars on each side of the plate can't improve matters (and almost certainly makes them worse) but plumbing such a plate as shown below, is GUARANTEED to cause distribution problems, as the spray bar that is supplied by the 2nd leg of the dual outlet feed tube, will get more than the first one, for the reasons given above;

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The same principles apply to distribution blocks as shown below;

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But once again some people can make even a bad design worse, as shown in the following 2 examples.

Adding an elbow introduces another factor (centrifugal force), that has an adverse effect on distribution;

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Putting all exits on the same side and feeding the fuel and nitrous from opposite ends, causes double trouble;

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More info to follow.

Author:  Turbobox [ Mon Sep 14, 2015 1:12 am ]
Post subject:  Re: Nitrous flow

Excellent post!

Author:  Noswizard [ Mon Sep 14, 2015 1:37 am ]
Post subject:  Re: Nitrous flow

Glad you like it Alex, would you like to try and figure out which of the 4 outlets will flow most nitrous, in the picture of the D-Block with the elbow fitted?

I've also just noticed that the plate with bars down each side, has the nitrous feed pipe entering from one side and the fuel from the other, so that throws in yet another factor that will screw up the distribution.

Now I could understand all this IF the knowledge to get it right wasn't available, but these people ONLY need to read my forum and website to LEARN ALL THEY NEED TO KNOW TO DO IT CORRECTLY!!!!!

Which begs the question, WHY DON'T THEY DO THAT, as they are all well aware that its here.

Author:  Turbobox [ Mon Sep 14, 2015 1:47 am ]
Post subject:  Re: Nitrous flow

Without being any sort of flow expert, I'd say it would flow the most out of the top-right outlet as the centrifugal force would slingshot the fuel around the 90* bend like a boomerang. That or the bottom-right, it's gotta go back into the direction it just came from.

Author:  Noswizard [ Mon Sep 14, 2015 2:06 am ]
Post subject:  Re: Nitrous flow

Brave of you for giving it a go but if it only had the 2 top outlets, it would CERTAINLY flow out of the top left.

Although I haven't carried out a test on these blocks with an elbow fitted (just with a straight entry), I would 'expect' the bottom left to flow most (as a combined result of centrifugal force and the inertia issue mentioned in the original post) or out of both left exits if the centrifugal force overpowers the force of inertia.

The way to think about this kind of thing is to imagine you are in a car and you drive round a sharp corner at high speed. In such an instance if you were to drive round a left hand bend 'you' (representing the nitrous) would be thrown to the outside of the bend (the right), which in the picture above as shown, is the left as we see it.

For your further information, it can take in excess of FOUR inches of STRAIGHT travel, for the nitrous molecules to recover from the effects of centrifugal force and continue to flow in a straight line of their own free will.

For your even further information ;) we put 'S' bends in our pipe work, to overcome the effects of centrifugal force, in a shorter distance, as it's not always possible to have 4 inches of straight pipe in some locations on some applications.

Author:  Turbobox [ Mon Sep 14, 2015 2:45 am ]
Post subject:  Re: Nitrous flow

I thought of that as a possibility, but I wasn't too sure. I tried lol.

Author:  Noswizard [ Mon Sep 14, 2015 3:28 am ]
Post subject:  Re: Nitrous flow

Well you learned plenty today and most people are lucky to learn just one thing, so you're well up on the game and its much better to learn than it is to show what you know and I'd certainly have been even happier to have learned 3 things today than shared them. ;-)

Author:  Turbobox [ Mon Sep 14, 2015 3:42 am ]
Post subject:  Re: Nitrous flow

So I'm having a bit of fun while I'm stuck at work...


Here's what my train of thought was:

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And here is what I'm speculating is happening based on your response:

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Author:  Noswizard [ Mon Sep 14, 2015 1:02 pm ]
Post subject:  Re: Nitrous flow

You are relying on the nitrous 'bouncing' off the walls of the component but the centrifugal forces and inertia forces are stronger, so they determine where the nitrous will flow.

I've roughly edited your pic to show how the flow will be distributed.

The darker the blue the higher the flow will be from the port nearest that area, as also indicated by the size of the arrow.

In most cases when I post information like this I've actually carried out flow tests and observed the results but in this case I haven't, so I can't be 100% certain about how the split will be. However, after 35 years of intensive research and learning how nitrous behaves, I'm 99% certain that it will flow as I've indicated.

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Author:  Turbobox [ Mon Sep 14, 2015 1:27 pm ]
Post subject:  Re: Nitrous flow

I got it now! :albino:

Author:  Noswizard [ Mon Sep 14, 2015 2:20 pm ]
Post subject:  Re: Nitrous flow

8)

Author:  kickstart [ Tue Sep 15, 2015 9:28 am ]
Post subject:  Re: Nitrous flow

I`m finding this intriguing !!!

Author:  Noswizard [ Tue Sep 15, 2015 11:36 am ]
Post subject:  Re: Nitrous flow

I was discussing this matter with an American customer and he sent me this reply;

You may or may nor recall from out previous discussions, so I will remind you that I am nearly finished with my PhD in mechanical engineering, with my main area of focus being experimental fluid dynamics. So I have a deep understanding of fluid flow, turbulence, etc. I do find it difficult to convey this sometimes complex and frequently non-obvious science to others. So I fully understand the problem with spray bars, turns, cross-sectional changes, etc. Unfortunately, it can be difficult to convince others of this. Even my business partner, who is a smart guy and usually listens when I try to explain complex engineering/physics subjects, just doesn't quite believe or understand me when I try to explain the impact of turns, sharp edges, cross-sections, and such. So I fully understand the problem with all of these spray bars on the market. At 50hp, it likely doesn't matter that much. At 150hp, now we are in a completely different realm.

Yes I understand all of the info in your link very well. In fact, it is usually taught reasonably thoroughly in an undergrad mech engineering program. But how well the students learn it really depends on the quality of the student. Unfortunately, I bet most mech eng graduates could not explain this concept to anyone, because most of them learn just enough to get by.

What you are talking about is fully-developed (sometimes called well-developed) pipe flow. Flowed along a sufficiently long, constant cross-section straight pipe, viscous forces cause the flow to become uniform both axially and radially, as it has reached a state of equilibrium. But anything that interrupts that straight uniform shape will disrupt the fully-developed condition. When making a turn, the inertial forces cause an uneven flow. Inertia carries the flow more heavily to the outside of the turn and, if the velocity is sufficiently high, the inertial forces will completely overcome the viscous forces and create separation at the inside of the turn, thus causing a localized area of eddy turbulence. Once the flow has passed the turn, the flow will once again return to the fully-developed state, assuming a sufficiently long straight constant section is there to again find equilibrium in the flow field.

Out of curiosity, how did you go about determining how much turn is needed in the "S" turn to counteract the unevenly distributed condition? It would be interesting to see what a good CFD simulation had to say about it.

As I have NO formal education in any of the subjects I work with, I get a great deal of satisfaction when someone who does have a high level of formal education on a subject, confirms that I managed to figure it out of my own volition, as in this case.

For anyone who hasn't already seen the following link, it would help to read this as well;
http://www.noswizard.com/pdf/optimum_di ... yblock.pdf

Author:  Turbobox [ Tue Sep 15, 2015 1:14 pm ]
Post subject:  Re: Nitrous flow

Of course you figured that out... you're THE WIZARD OF NOS!!! ROFL

Author:  Noswizard [ Tue Sep 15, 2015 6:43 pm ]
Post subject:  Re: Nitrous flow

With that in mind it's only to be expected I guess. :lol:

Author:  kickstart [ Wed Sep 16, 2015 7:10 am ]
Post subject:  Re: Nitrous flow

On the next dry day I`m going to go right through my plumbing after seeing that link.

Looks like shower head D blocks are the way forward for me too :yes:

Author:  Noswizard [ Wed Sep 16, 2015 8:22 am ]
Post subject:  Re: Nitrous flow

kickstart wrote:
On the next dry day I`m going to go right through my plumbing after seeing that link.

Looks like shower head D blocks are the way forward for me too :yes:


Showerheads are the best option for a single solenoid feeding multiple cylinders but even they MUST be plumbed in a specific way to achieve perfect distribution, plus there are good designs (WON) and not so good (the rest), so just like everything else don't be fooled by external appearances.

I'll be making a post about the 'better' distribution options ASAP.

Author:  Turbobox [ Wed Sep 16, 2015 12:52 pm ]
Post subject:  Re: Nitrous flow

LOL you're gonna be busy today.

Author:  kickstart [ Thu Sep 17, 2015 9:19 am ]
Post subject:  Re: Nitrous flow

Yes, regarding plumbing the showerheads, I think I read in another thread about making sure there`s a 6" straight run of pipe before the fitting - now I understand why.
If there`s a bend before a showerhead it could possibly be the worst case scenario as the majority of the gas could easily be directed to 1 cylinder :yes:

Author:  Noswizard [ Thu Sep 17, 2015 1:12 pm ]
Post subject:  Re: Nitrous flow

Absolutely correct Kickstart. :yes:

Author:  Noswizard [ Thu Sep 24, 2015 1:34 am ]
Post subject:  Re: Nitrous flow

I've been otherwise occupied so I haven't had time to make further tech posts on this matter yet but a customer directed me to the following Facebook thread (unfortunately) and as it was related to this thread, I thought I'd better make a post;

https://www.facebook.com/10617110273909 ... =3&theater

When I look at this picture it is BLATANTLY OBVIOUS that the distribution is APPALLINGLY BAD and yet a huge number of other people have missed that FACT entirely.

The FACT that this is yet ANOTHER COPY of a TERRIBLE concept, just goes to prove how IGNORANT the people behind these products are, as anyone with any brains would see it was a bad design and would NOT COPY IT!!!!

Are these people blind or plain stupid?????

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Why is it so difficult to see what is so OBVIOUS to me?????

This is the post I made on the thread above, which will probably be deleted and/or ignored or worse still some IDIOT/S will reply standing up for this PIECE OF JUNK;

One of my customers pointed me to this post but I wish he hadn't. The distribution on that plate would be A JOKE if the consequences weren't so dire. There aren't even 2 plumes flowing the same amount or at the same density or even in the same direction, never mind all 16 matching. Perimeter plates are one of the worst ideas ever conceived of, for many reasons and you've just managed to make yet another perfect example, of why that is the case. People like you should be BANNED from creating such terrible products, to save your customers from the consequences of such appallingly bad ideas. How you sleep at night is beyond me, when you are responsible for so much destruction of customer's engines, as a consequence of your total lack of any understanding of nitrous flow.

Author:  Noswizard [ Thu Sep 24, 2015 10:12 pm ]
Post subject:  Re: Nitrous flow

Can you believe the replies this US nitrous 'EXPERT' :omgrofl: has posted to my technical posts.

https://www.facebook.com/10617110273909 ... 71/?type=3

UTTERLY PATHETIC.

Author:  kickstart [ Sat Sep 26, 2015 8:55 am ]
Post subject:  Re: Nitrous flow

I`m truly amazed (even as a novice), that:

1) they would even publish a picture like that to showcase their latest efforts
2) the scores of people who have (based purely on that picture) expressed their intentions to buy one ASAP, and saying what a great & pretty picture ???????

If the entire concept was to dump a shed load of gas in a hole ........... I guess they succeeded :yes:

Looks like I bumped my head too :lol:

Author:  kickstart [ Sat Sep 26, 2015 9:01 am ]
Post subject:  Re: Nitrous flow

Trev, purely academically, would I be right in thinking that the pic above shows that - assuming all the holes in that perimeter plate were completely identical - ........... there seems to be more gas pressure from the right hand n2o inlet pipe ?

Author:  Noswizard [ Sat Sep 26, 2015 2:46 pm ]
Post subject:  Re: Nitrous flow

kickstart wrote:
I`m truly amazed (even as a novice), that:
EXACTLY even as a NOVICE you can see it's not right, so how come this US 'EXPERT' can't see it!!!!! This guy is considered a know it all superhero not only in the US but also here in the UK, while I'm laughed at by the same IDIOTS.

1) they would even publish a picture like that to showcase their latest efforts
EXACTLY RIGHT, which PROVES ABSOLUTELY that he has NO IDEA what he's doing. I nearly fell of my chair laughing, when he stated that you can't tell much from a picture, when a picture (or a video) is the ONLY WAY to tell what is going on and what I use to perfect my designs.
Nitrous flow is fast and creates a fog and as a consequence it's hard to appraise while its flowing. Taking pictures and/or video's enable you to review the results either frame by frame or at a slower speed, which obviously gives you a better view of it.


2) the scores of people who have (based purely on that picture) expressed their intentions to buy one ASAP, and saying what a great & pretty picture ???????
Whoever coined the phrase "The BLIND leading the BLIND" summed up this situation EXACTLY!!!!! Put a BLIND shepherd in charge of a flock of BLIND sheep and this is what you end up with - all of which is going to produce a bunch of melted engines.

If the entire concept was to dump a shed load of gas in a hole ........... I guess they succeeded :yes:
Yup that's all they've managed to do but the concepts they should be working to achieve are;
1) EVEN distribution - which a perimeter plate can NEVER achieve - this one is more uneven than some of the others
2) Nitrous flow that ASSISTS airflow to enhance cylinder filling - which requires the nitrous to flow in the OPPOSITE DIRECTION to that from a perimeter plate
3) Avoiding nitrous flow that disrupts the airflow - which this plate is causing BOATLOADS of

To make matters worse, this plate is OBVIOUSLY VERY BADLY machined, as the direction, shape and density of the plumes are ALL OVER THE PLACE and not even 2 are the same as each other. Add all that to inherent problems of the perimeter concept and even a fool should be able to guess the consequences and yet our superhero is OBLIVIOUS TO IT ALL and 'thinks' he has created a masterpiece - WHAT A TOTAL IDIOT HE IS!!!!!


Looks like I bumped my head too :lol:
:yes: Yes and what a STUPID way to respond to so many technical comments, rather than reply with technical answers to support his product. Obviously as all the tech comments I provided were FACTS, he couldn't come back with any TRUE technically defensive responses.

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