NITROUS OXIDE ( nos / n2o ) advice forum

Ok, dead easy.
I need one tangible benefit of braided hose for the transfer of liquid nitrous oxide and i'm struggling.

Meets NHRA/IHRA safety requirements.

Beyond,

That's not an example of a "benefit of braided for the transfer of nitrous", that's an example of outdated rules based on ignorance and arrogance.

It's even worse over here because our Drag racing organisations didn't even think their own rules up, they just copied and followed US rules like a flock of sheep!!!

Even after I wrote pages of reasons why the US rules made nitrous use more dangerous than it could be with the use of nylon pipe and suggested a good number of better more appropriately rules, not a single one was implemented.

Here's an example of a better rule;
Most engine failures occur on the start line when the engine stalls (because of a nitrous spit back) followed by a violent ignition of a static dose of nitrous and fuel at restart. I have a simple & cheap device that would prevent this ever happening (I call it an Ignition Delay Unit that cuts the coil supply for a few seconds each time to try to start the car).
Now that's what you call a safety rule unlike the garbage about braided hose!!!

The only example of a benefit I know of, is that it's available in a large enough size to flow serious power figures and still be flexible and for that you have to pay the price of flow problems.
However on low power figures I'm sure there isn't a single example of a benefit. ;-)

Regards

Talking about the race rules for a moment.
What exactly do they say ?
Because if they allow braided pipe but not plastic then that doesn't make sense.
Braided isn't a continuous metal shield which is whats demanded by most racing organisations.

(LOL Just how flexible does the larger sizes need to be for the drag racers ?
Solid mounted engine, well damped and mounted tubing..................)

I'm sorry Beyond, while its a valid point i've got too many ways around it. I need some sort of tangible benefit or this article is going to be decidedly one sided.

It is too a benefit for those that want to race.. If you don't have it you put the car back on the trailer and watch. Loopy only asked for a benefit, not which one flows the best.

I will definately agree with you about flow rates, there is no doubt that the standard Nitrous (braided stainless PTFE hose) lines have a flow restriction due to the fitting design. I am in total agreement with you on that point.

I do feel that the stainless covering has some safety benefits to prevent the hose from getting damaged during a wreck. It's hard to argue against that layer of stainless not being tougher than unprotected hose.

Your delay device wouldn't have prevented most nitrous backfires and resultant fires that I have seen. THose guys aren't attempting to restart the car, they are trying to get the heck out of it before they burn to death. Here's a video of a rather nasty one at Piedmont last year It's scary to watch. http://www.memphisracingscene.com/video_gallery/jay/piedmont-fire.mpeg

I did a quick search on the net for this rule, I'll look it up this evening in my book, but I think this sounds like the rule which is from the Sportsman section of the book, it's likely listed in other areas as well.

"Commercially available nitrous oxide system prohibited on supercharged V-8 engine, permitted on all other engines. Nitrous bottles in driver compartment must be equipped with a relief valve and vented outside of driver's compartment. Bottles must be stamped with a DOT -1800 pound (124 bar) rating and permanently mounted (no hose clamps or tie wraps). Hoses from bottle(s) to solenoid must be high pressure steel braided or FIA permitted hoses. External heating of bottle(s) prohibited."

Trevor a lot of this would be a moot point if your fitting design could be used with the ptfe bottle lines wouldn't it? Or perhaps if your lines had a steel braided cover??

Hang on a moment Beyond.
Firstly i asked for a tangible benefit of braided hose for the transfer of liquid nitrous oxide.
NOT a debate on rules

Now think about your "protection" argument for a moment.
If it gets trapped by bent metal the braid will exert a higher pressure per square inch or rather thou on the weaker PTFE liner than non shielded plastic hit directly by a metal edge.
IF the pipe does get ruptured in a crash then what happens ?
15lb of fire extinguishent gets dumped into an open cockpit hopefully buying a few more seconds of time for the driver.
OK, so it comes at a price of raising the oxygen level once the atmosphere in that cockpit gets to a few hundred degrees.
Given the choice i'll dump nitrous everytime.

I have seriously tried to cause a worse fire with it and unless the compartment is closed and unless the fire is out stripping the oxygen availability I haven't managed it yet, even spraying directly onto white hot steel didn't do much apart from cool and warp the steel.
Now i'm not qualified to have this discussion but I have had this conversation quite a few times with people that are, none have disagreed as yet.

Now, wouldn't a rule stating "Nitrous lines must be enclosed in a metal structure of continous design wherever it enters the drivers compartment"
Solve all these fears ?
How about another one "All nitrous systems must be fitted with a failsafe automatic shutoff device to seal off the bottles contents in the event of an accident"

I'm not here for a fight Beyond, but don't expect me to defend dumb rules that don't make sense.

Thanks, i hate discussing whats not in front of me.

The compression style fitting isn't compatable with the PTFE Liner of braided hose, it simply doesn't have any physical strength so can't be retained by it. The braided steel is what does all the pressure restraint, NOT the PTFE.

Do you reckon simply covering the plastic hoses with "decorative" steel braiding would pass tech ?
Same thing but with the physical strength of "our" plastic isn't it ?

Loopy, I'm not arguing. In fact I'd love to find away to work around the rule issue. Being legal for the rule book is a major benefit, sorry you don't see it that way.

I'm just stating that the primary benefit of the stainless type is that is meets the current NHRA/IHRA rule book. There might be an alternate in the FIA rulebook, but I don't have a copy of that one.

Personally I have very little fear about nitrous lines for the same reason you've mentioend. Fuel lines are a different story. Getting the rules changed is something I can't do, in fact it might be quite difficult for any manufacturer to do that is not a supporter of NHRA. Getting those rules changed may also be a political issue as much as a safety testing issue.

I think everyone has the most to gain in figuring out how to fix the fitting issue with the PTFE lines or finding a source of braided sheath nylon ? line...

From what I have seen, they do not specify the inner hose material. I think a braided steel cover over the Nylon/Plastic line would meet the letter and the intent of that rule.

They are not specific as to brand or specification, burst pressure is not even mentioned that I have seen. There is some wording in different areas about it being available from a manufacturer, but have never heard of them checking on things like that.

Beyond,

You're right about the political aspects influencing US rules but it's plain stupidity that makes UK organisers follow them.

By the way Loopy and I are not against 'you' we're just against the braided pipe and the rule makers stupidity. ;-)

Regards

Beyond>
Just to make this clear.
I know exactly what rules are and what they mean.
I'm not fighting YOU.
But with the rule written in such a bizarre way how the hell can you get around it ?
So lets see now, a steel hydraulic pipe would be illegal because it isn't braided ?
We may have some stupid rules, but they at least sort of make sense !
What a crazy state of affairs

Your not looking at it from the proper "perspective" to understand why they are written that way. Say you're Mr. NHRA tech book writer. Who do you ask about what to put in the rule book? Why, of course you ask the Nitrous manufacturers (who by the way support your org) what they suggust. Stainless braided is what they sell and support.

This is based on mfg. recommendations, not engineering or technical studies.

The "or" in this qoute means write a check to us and we'll approve your lines if they are safe enough which they are.

"Hoses from bottle(s) to solenoid must be high pressure steel braided or FIA permitted hoses".

Beyond,

If only the Brits had done it that way I'd have been trouble free because I'm the only UK manufacturer but like the bunch of sheep they are, they 'followed' the US rules, assuming they were made because they were the best options!!!!

What a joke!!!

Regards

Only advantage i can see is they are less likely to chafe through if installed completely incorrectly by a total moron.
Anyone who is that stupid though, will find another way to destroy their car anyway, some people are just too stupid to be allowed near a car (or a pen to write a rulebook it seems!)

Actually Chip it's easier to 'snag' a strand of the braid on a rough drilled edge than to rub through the thick wall of our nylon pipe, been there 'seen' that!!! LOL

Regards

Fair enough, its also easier to kink judging by the picture loopy showed us (and kinking is another common instalation problem), quite surprised at just how good the new blue stuff is to be honest, as ive not tried to kink it, those test results were awesome compared to the braided rubbish

The burst pressure it what amazes me most, it's in the region of 8,000 psi !!!!!

We're still trying to get an option on a bigger bore for our higher power systems as well as better heat resistance to deal with high temps on our export systems, so there's even better to come.

Regards

I checked my 2005 rule book last night, the rule says basically the same thing that I posted earlier, except where it says "or FIA approved" it now says "or NHRA approved".. reads the same otherwise.

For the most part it needs to look similar to the stainless braided teflon hose most manufacturers use. If it looks about the same it'll pass most inspectors I would assume regardless of what material is on the inside.

Didn't NX introduce a black hose a few years ago? Does anyone know if that got accepted to use at NHRA events? I don't think it has the braided cover but I've never looked at it myself.

NX does have the black hose now and it's nothing special. The end fittings are the same as braided so you still have the same problems associated with braided.

Pretty much we are going to have to sit down with the NHRA and IHRA to explain our case and hand over some money if we want the nylon legalized.

Thats the "race" hose they sell.
Simple old TPE thermoplastic pipe, but guess what ?
Its high pressure AND braided (aramid fibre) so that "should" fail since its not "steel" braided.
Christ, this is madness.

I also see "commercially available"
Now lets just say you modified your solenoid in the slightest way, it wouldn't be commercially available so would technically be illegal !

What a wierd way of writing rules

I believe the black 'race' hose is worse than steel braided for flow as the end fittings for this stuff have very thick sleeve walls. This means the hose itself is very huge internally to accept an end fitting that can flow enough. I believe the I.D. of the 4AN hose is .25" if I'm not mistaken.

Guess why ?
I'll give you a clue;
I get quite a good discount on that EXACT hose and fittings
(It's even WORSE than braided for expansion)

I really don't know. A supply house said the fitting walls have to be thick as it's a crimp fitting, yet steel braided is a crimp fitting also and the brass sleeve used is very thin.

Did you notice NX claims the high flow rates as a selling point and people will think this is a good thing. High flow doesn't equal efficiency and optimization.