Outer Limits 4x4 Board

has anyone purchased the air up system? if so can they send me a couple of close up photos of the regulator set up, from different angles? i have a co2 cylinder and an account with BOC, and now ive found a place that does custom regulators, couldnt be too hard to have the regulator knocked up! thanks guys!

cant help you with the air up system. But when you work out the regulator. I would be interested in some details and cost. As I just received a Fire services BA cylinder. And plan on using it for tyres and air tools etc.

first quote is $250, but will find out more!

contact Bee Bee off this board he is sponsored by this mob... and runs it on his luxy

eliteforce32 wrote:contact Bee Bee off this board he is sponsored by this mob... and runs it on his luxy

Im fairly certain your not going to get a sponsored person to show someone pictures so he can just go and make his own. And if Dave was to do this im pretty sure Air Up would be real pissed at him.

Any place that sells regulators and has any idea about them will be able to sell you a reg to suit this application. As far as im aware the Air Up Reg is not custom made for this Application.

I don't see the point after a while, with it being a bottle it'll be great at the start then it slow down then really slow then then be empty.

How long would there little bottle last for?

There reg is probably just a fine adjustable one.

Hope this helps. It has fairly high pressure. Let me know if you can get something similar made and what price etc. Thanks, Tys

zagan wrote:I don't see the point after a while, with it being a bottle it'll be great at the start then it slow down then really slow then then be empty.
How long would there little bottle last for?

My very limited understanding about them, having only seen Roothy's advert for one on a DVD, is they'll fully inflate about 20 tyres.
That's a lot of re-airing up before having to pay $20 - $30 for an exchange tank, and considering it's under 1 minute per tyre or something like it. It sure would make for a very short air-up stop at the end of a trip.

But I do agree, their prices are insane. Considering what it is, I'd assumed max a few hundred, I nearly choked when told the full price and decided I'd keep using the twin head compressor, which is only a little slower, and a whole lot cheaper.

But I'll watch the thread with interest if you do find a cheaper way, as it has advantages.

I am also sponsored by air up. The cylinders maintain high pressure right till the end as the liquid C02 changes to a gas to fill the missing space. therefore they stay at about 1000psi from memory. They fill tyres so fast its crazy, and they are sweet for fox shox. They supplied me with what they call a "duffy" valve named off one of the other guys on this forum. Its an inflator adjustable to 200psi

I looked at getting boc (account there too) before i was sponsored but the regulators etc are not designed to flow high volume and freeze shut. Air up is pretty good value for what you get. The coiled hose stores well etc, you can buy holders for the cylinders etc

Cheers bru

i am looking at an air up like setup.
ill have more details shortly but mine will cost me all up about 300 bucks. (buying new tanks etc). a refill will cost between 10-12 bucks. and the air will be dryer than standard c02 sounds cryptic but once i prove it works ill post up details for you all.

bru21-The regs that BOC sell wont even come close, the output on them is something like 8psi. but the company that they get their regs from will custom build a reg for around $250 (already spoken to them) and i can have a maximum pressure set as well, say 50psi, and if i over inflate, it will cut out at 50psi! will let you know more when i know more.

tys-Thanks mate, very helpful!!!!

update- ok, pics passed on to regulator company. will find out more tomorrow. if i can get a discount on a bulk buy, would anyone be interested?

Yer I would be interested. Depending on what cylinder adaptor they can come with. As I will be using a STD Fire service Steel breathing cylinder. Trying to get some light wieght cylinders but they want money for them.

ok, i can get them for $150.

no one interested anymore?

Price appears good. Whats some details on the reg- flow rate, pressure etc. Also what type of connection are they?
I havent had time to find out what a std fire service thread size and type yet.

full-boost,
Good luck with you rip-off venture hope you hit pay dirt
With a max pressure of 50psi whoopee, when you reach 450psi without freeze clogging I will then feel the need for some more regulator development

Davo

why cant someone use o2 instead of co2?

Dangerous Goods issues. O2 big time oxidiser (y'know being Oxygen and all)

nitrogen would be the go wouldnt it? doesnt expand with heat as readily as co2 and o2? i may be wrong

co2 is used as i described above. co2 maintains constant pressure turning from liquid to gas. other gasses do not (except for lpg) at room temps. this means other bottles are heavier as they need to hold 2-3000 psi. this is far more dangerous than co2 at 1000psi

smiley_smoke wrote:nitrogen would be the go wouldnt it? doesnt expand with heat as readily as co2 and o2? i may be wrong

Yes, you are wrong.

The formula for calculating expansion of a fixed volume of gas (PV=nRT) has nothing to do with the gas type - H2, He, N2, O2, CO2, doesn't matter.

Nitrogen is used because it's dried as it's compressed - and that's the trick.

Standard air compressors heat the air as they compress, so any moisture in the air is converted to steam and sent down the air line. Once in the tyres, as the air expands again, the steam cools and condenses. No problem.

When you drive, the air heats up again, and some of the condensed moisture evaporates again - and this change from liquid to gas creates a higher (and less predictable) pressure change than you would get from simply heating a gas.

When you order bottled Nitrogen gas, it's been dried - so the tyres don't have any moisture in them, and the pressure increase (due to temperature change) is much less, and more predictable.

ANY dried gas will do the same - I expect the Air-Up CO2 offers the same benefits as bottled/dried Nitrogen.

As Bru points out, the big benefit of CO2 for Air-Up is the liquid storage. I haven't done the sums, but I would guess you'll get many more fills from a bottle of liquid CO2 than any similar sized compressed gas bottle.

Cheers,

Scott

Witchdoctor - why the need to be a smart arse? The reg guy I spoke to says as long as you are not running it for long periods (10-15 mins, constant running) it will be fine. as it only takes around 1 min to inflate a tire, x4 thats 4 mins......no probs! unless your driving a semi that is. and although i dont know much about gas storage, the reg dude said that the regular cylinders from BOC are dry gas (the cylinder with the painted "hat" on top) the "liquid" ones have a stripe down the side, and are used for LIQUID applications. yes i know when you shake a bottle of Co2 its a liquid inside, but it comes out as a gas, it doesnt come out as a stream of liquid! you can ring him your self, its John at gasgep, in coburg melbourne! when you have found out some more info you can post your appology just bellow this, thanks

turps - flow rate will be the same as you see on the air up reg. i sent him the pics and he said he can make it up the same as the air up, it just wont have the writing on the inside like the air up (lockers,tools,tires)

people - you dont have to go with this idea, im forcing no-one, ive given the name of the supplier (gasgep) you can even ring them up yourself and find out the same info, and you will even get the same price, as i HAVE NOT ADDED ANY ON FOR MYSELF TO RIP PEOPLE OFF!!! i was just trying to figure an affordable way to do the air up system, do all the ground work (numerous phone calls, emails, etc) at my own cost, to help out like minded off road enthusiasts! then i get comments like "Witchdoctor's" and i think "why bother, i will keep this idea for myself" but i'm sure Witchdoctor is the minority, not the majority, and will continue to find out more info on this topic, for those who are interested!

just my 2c worth.

full-boost, have a look at Witchdoctor's web site.

-Scott- wrote:

smiley_smoke wrote:nitrogen would be the go wouldnt it? doesnt expand with heat as readily as co2 and o2? i may be wrong

Yes, you are wrong.

The formula for calculating expansion of a fixed volume of gas (PV=nRT) has nothing to do with the gas type - H2, He, N2, O2, CO2, doesn't matter.

Nitrogen is used because it's dried as it's compressed - and that's the trick.

Standard air compressors heat the air as they compress, so any moisture in the air is converted to steam and sent down the air line. Once in the tyres, as the air expands again, the steam cools and condenses. No problem.

When you drive, the air heats up again, and some of the condensed moisture evaporates again - and this change from liquid to gas creates a higher (and less predictable) pressure change than you would get from simply heating a gas.

When you order bottled Nitrogen gas, it's been dried - so the tyres don't have any moisture in them, and the pressure increase (due to temperature change) is much less, and more predictable.

ANY dried gas will do the same - I expect the Air-Up CO2 offers the same benefits as bottled/dried Nitrogen.

As Bru points out, the big benefit of CO2 for Air-Up is the liquid storage. I haven't done the sums, but I would guess you'll get many more fills from a bottle of liquid CO2 than any similar sized compressed gas bottle.

Cheers,

Scott

PV=nRT is the characteristic gas equation and isn't quite the one for the expansion and compression of gases.

Boyles's and Charles Laws are the ones for the expansion and compression of perfect gases:

P1*V1 = P2*V2 & V1/T1 = V2/T2

You are right in saying that each gas type expands proportionally to the other. However each gas has a different mass and therefore occupies a different volume. Thus if you had the same mass of N2 in your left hand as you had CO2 in your right hand, the CO2 would occupy a larger volume (at constant pressure of course,) but they would both expand proportionally.

PV=nRT is dependant on the molar mass of the gas you are considering and will thus vary from gas to gas depending on what your calculating.


.....I think

KaMo wrote: PV=nRT is the characteristic gas equation and isn't quite the one for the expansion and compression of gases.

Boyles's and Charles Laws are the ones for the expansion and compression of perfect gases:

P1*V1 = P2*V2 & V1/T1 = V2/T2

These formulae are derived from PV=nRT. n & R are constants for a given body of gas. If T is also constant, than P1*V1 = nRT = P2*V2. (As a student, we had to derive PV=nRT from Newton's Laws - it's actually pretty easy when you can remember exactly what n & R mean.)

Rearrange the formula to V/T = nR/P. If n, R & P are all constant, then V1/T1 = nR/P = V2/T2.

You are right in saying that each gas type expands proportionally to the other. However each gas has a different mass and therefore occupies a different volume. Thus if you had the same mass of N2 in your left hand as you had CO2 in your right hand, the CO2 would occupy a larger volume (at constant pressure of course,) but they would both expand proportionally.

PV=nRT is dependant on the molar mass of the gas you are considering and will thus vary from gas to gas depending on what your calculating.


.....I think

All this is correct if you are trying to compare different bodies of gas - mixed or otherwise. That's too difficult for me - I'll leave it to somebody else.

For a body of gas trapped inside a tyre (ignoring any variation in tyre shape with pressure ) you can consider the n, R & V components to be constant. Temperature and pressure are your only variables, which will vary in a predictable manner, independently of the gas mix.

Add water, and you're introducing a phase change (liquid to gas) and you lose the predictability. This is why racers use Nitrogen - it's dry.

....looks like im going to fail my thermodynamics exam on thursday

full-boost, I think it is good what you have done and it is a good price to me. I dont know much about the properties of gas and liquid though so i am staying out of that one! Unfortunately i dont need another set of gauges at the moment but i thank you for your time and effort.

-Scott- wrote:full-boost, have a look at Witchdoctor's web site.