Outer Limits 4x4 Board

tweak'e wrote:

chimpboy wrote:The bottom line is that you are definitely going to run your compressor less and it is going to get hot less, the air you are using will be cooler rather than hotter, ........

i don't think thats the case. your still pumping the same amount of air with or without the tank. if anything the tank will require more use of the pump due to pumping tank up to higher pressure (than the tires) and have more heat due to the higher pressures.

the only thing is the pump will run constantly (ie long on time, long off time) not so stop/start as you change tires or use locker. its a lot easier on the motor not having to start so often.

The tank acts as a cooler for obvious reasons. Of course if you are just draining the tank to fill tyres the benefit of the tank is marginal (but there is one). For pretty much any other purpose a tank set-up is clearly better, not just marginally better. It is also not really true that it's better to go long time on, long time off for any compressor I have seen because they are designed to run a bit, cool down, run a bit, cool down, etc. I guess frequent starting might not be great but it is still not as bad as running continuously for ages; if you have a thermal cut-out on your compressor (and you should) then it will switch your compressor off while you're using it. If you don't have one then you will be roasting it.

But let's not go round in circles any more, we obviously just have a different take on it, I will just stand behind the fact that every single serious professional use of compressed air on every well set-up vehicle out there involves a tank, and filling a tank is the exact job the compressors are specified for.

Think about it another way, if someone said "bah, forget having a tank on your workshop compressor it's pointless, just run a compressor and a hose without a tank" you would not listen to him, so why is it different on a vehicle?

Just my thoughts, if I'm wrong I'm wrong.

chimpboy wrote: Think about it another way, if someone said "bah, forget having a tank on your workshop compressor it's pointless, just run a compressor and a hose without a tank" you would not listen to him, so why is it different on a vehicle?

Just my thoughts, if I'm wrong I'm wrong.

discussions are always fun

with workshop compressor (or endless air) the compressor can pump more than you use. with low flow compressors the pump constantly making the tank redundant.

but each to their own

Also, having a tank will mean that the time taken to pull the tyre chuck off, put valve cap on, move to the next tyre, cap off etc, will have the compressor running continuously filling the tank to dump sraight into the next tyre, you'd be effectively getting the most out of the compressor.

No i don't have a tank - just the tiny one on the ARB compressor, i'm in no hurry to air up - would be handy to seat beads though, changed a tyre at home with levers the other day and had to fire up the peerless to seat it, got to wondering what i'd do if it happened in the sticks - maybe a can of lynx

chimpboy wrote: That makes a lot more sense. Personally I would prefer to have 150 psi in the tank and use a regulated feed to lockers (or to a second tank for lockers).

Or have two compressors

One that fills the tank and one that runs the lockers, that way you can run a hose off the tank and also from the air locker compressor so you can air up two tyres at once!

Made this air tank just recently, gets alot of looks. I could make tanks with model spesific mounting kits I guess...

That tank is about 5-6ltrs, anyone got any ideas on what would be the best volume..?

bigger is better

on another forum someone has a 48 litre tank and that pumps one tire up before the compressor kicks in. (not sure on start pressure probably 80psi cut out 100psi)

By my rough calculations, if your tank is at 150psi and about 20 litres in volume it will get a 33 (roughly) from 10 to 30 psi without the compressor having to do anything. In reality the compressor will actually kick in for some of that time.

Tank pressure makes a big difference, twice the pressure is basically equivalent to twice the volume.

Dunno on perfect volume, probably the biggest you can fit without going stupid basically, but also no bigger than your compressor can fill up while staying within its duty cycle.

Thanks for the pics, some nice setups there

Might have to get under the surf and see where I can mount a tank.

Cargo space is so bloody small in the surf (especially with a sub and speaker pods) that I'd rather run the tank outside the car.

Just a question with setup. (probably a stupid question too )

Do you have to change where the pressure switch sits on the arb compressor if you run a tank?

I'm assuming that the all the lines, and the tank create one big tank, so where the pressure switch sits is irrelevant?

endo wrote:I'm assuming that the all the lines, and the tank create one big tank, so where the pressure switch sits is irrelevant?

That's my understanding of it.

endo wrote: Do you have to change where the pressure switch sits on the arb compressor if you run a tank?

I'm assuming that the all the lines, and the tank create one big tank, so where the pressure switch sits is irrelevant?

The pressure switch on the ARB compressor cuts out at 80 psi and is only there for use with ARB air lockers. If you are using this compressor to fill a tank, I would be buying an after market pressure switch at say 150 psi and mounting it where ever you want to mount it.

The ARB compressor has a built in Thermal cut out and a blow off valve at 180psi.

http://www.arb.com.au/resources/pdf/airLockers/3-04.pdf

70-100psi for the CKMA12 / 24

While we are on the tank topic,
saw a bloke the other week pump his tyres up in less than 3 seconds each.
what i want to know is how?
the air hose was quite large, but is he using gas instead of air?
and how much flow can a normal valve take? or would he have to have an open one way hole for a valve?

Rodeo98 wrote:While we are on the tank topic,
saw a bloke the other week pump his tyres up in less than 3 seconds each.
what i want to know is how?
the air hose was quite large, but is he using gas instead of air?
and how much flow can a normal valve take? or would he have to have an open one way hole for a valve?

Was it on his mountain bike?

endo wrote:http://www.arb.com.au/resources/pdf/airLockers/3-04.pdf

70-100psi for the CKMA12 / 24

My bad.

I was close though without looking at the spec sheet.

T_Diesel wrote: My bad.

I was close though without looking at the spec sheet.

I went hunting to make sure... Coz i was sure the ebay add said 70-100

Had me worried for a sec

Rodeo98 wrote:.......
and how much flow can a normal valve take?

good question. like to know that myself.
i know some people fit bigger higher flowing valve stems in their tires.

theres also CO2 systems and endless air that will pump tires up really quick.

i had a weird thought......
seeing as the compressor tries to pump the tank and the tire at the same time, why not fit some sort of valve so it bypasses the tank.
maybe some sort of pressure valve so once the tank got down to max tire pressure it shut the tank off.
that would give you the advantage of the tank being precharged without the drawback of trying to pump it back up while pumping tires up.

chimpboy wrote:

endo wrote:I'm assuming that the all the lines, and the tank create one big tank, so where the pressure switch sits is irrelevant?

That's my understanding of it.

Pressure is distributed equaly and undiminished in all direction's. so in short it does not matter were the pressure switch is in the circut.

What CFM does the ARB one run out?

If you are after quick air you might want to look at an AZ OB2 comp. 3.8cmf 12v and is 100% duty cycle at 200 psi.

Viair's are good too but are less cfm then the OB2

We use allot of these in air suspension setups. Just thought it was worth a mention.

Cheers

don't forget thats only the claimed specs. what they actually do can be far from it.
ARB is about 2CFM (60l/min) at free flow. they claim 75l/min which is fairly good. some claim 150l/min but do around the same as the ARB.
obviously it gets less as the pressure goes up, some do better at higher pressure than others.