[zooky08]

It's either 1/4 or 3/8. I can get either hose from work.
I did some tig work for my breathers

[Bugsta]

I used an elbow BSPT tapped in the rear diff bung hole...
[url=http://]http://www.fittingsexpress.com.au/product/3109[/url]
I did have one on the front but it kept getting broken by the chasis under flex, so I sifted through Repco's hose collection till I found a right angle that was the right ID with the right bend. I cut it down, inserted a shprt piece of airline hose as an adaptor and then the 1/4" breather line. Clamped it off and its been great till I ripped it off the last trip. This is due to the use of cable ties around the radius arm. I have on order some rubber covered pipe clamps that I should be able to mould to hold the locker airline and breather pipe, bolted to some nutserts inserted into the inner side of the radius arm... no more cable ties to get snagged.

And 4 bulkheads neatly installed in the air box...

[url=http://]http://www.fittingsexpress.com.au/product/3116[/url]

and relbow tailpieces to attach the pipe...

http://www.fittingsexpress.com.au/product/3182

Received a Stebel Nautilus air horn for christmas (how did Santa know) and that has an air pipe adaptor so I might plumb that into the air box as well. I think the only place it will fit is behind the wing of the ARB bull bar.

[Scales]

guys if there was any more debate about my hose sizes etc. i just dropped the diff oil after going to the cape and also a MASSIVE bog that was in some seriously muddy water and i had hot diffs. The oil looked spotless.

So there you have it, a good 6 months later and plenty of wheeling and all good.

also had plenty of engine bay hose out sessions and accidentally wet the breather filter, still no water ingress. Im guessing thats thanks to the fact the filter is on its side.

[honks]

That filter looks like an oiled filter similar to a k&n filter which would have to help repel light splashes of water,

[SierraDan]

It'd have to be oiled though...

Sweet job man. My fuel filters have done me good.

[Scales]

SierraDan wrote:

It'd have to be oiled though...

Sweet job man. My fuel filters have done me good.

Nope, shes a dry one. nothing stopping ya from giving it a squirt of filter oil if you were that way inclined. im happy with it the way it is, oil=dirt in my eyes and its not sucking constantly so yeah.

[jdk81]

Diff volume calcs.

For interest sakes air volume is = to diff oil volume, as diff oil is approx 1/2 way up the diff.
Temp of air whilst hot is assumed to be 328Kelvin, temp of cool diff will be assumed to be 288 Kelvin, to give us an extreme example (60 Degrees C hot, 15 Degrees C cold).

Diff fluids 1.5L and 1.3L. 1.5L will be used as the volume.
And 1/4" air line.
Will assume pressure is constant (standard atmospheric pressure), and check the Re number, contrast this to flow dynamics and determine if there is a need to reiterate.

Change in Volume
P1V1/T1 = P2V2/T2 ===> 1.5/328 = x/288 ==>x = 1.317 L , so a change in approx 183 mL (cm^3)

Velocity inside the 1/4" pipe
A= pi()*((2.54/4)^2)/4 = 0.3167 cm^2
Velocity = Volume/Area = 183/0.3167 = 578 cm/s = 5.78m/s

Reynolds Number
Re= rho*u*D/mu =
rho = 1.225 kg/m^3
D = (25.4/1000)/4
u = 5.78m/s
mu = 1.78 x 10^-5 kg/ms
Re =1.225*5.78*(25.4/4000)/(1.78*10^-5) =2526

Checking the moody diagram, its right in the transition.
We can do a headloss over 2m of 1/4" pipe.

headloss = h = (f*L*v^2)/(D*2*g)
Pressure loss = rho*g*h
Pressure loss/rho = g*h
Pressure loss= (f*rho*L*v^2)/(D*2)

f = friction factor = 0.08
L = 2m
v = 5.78m/s
D = 1/4 * 25.4/1000 = 0.00635 m
rho = 1.225 kg/m^3
Pressure Loss = (0.08*1.225*2*5.78^2)/(2*.00635) = 515.6 Pa (0.075 PSI)
Dont need to iterate as the change in pressure is relatively low
std atm = 101300 Pa, 101300-515.6 = 100784.4.
SO we have a 1/2% difference. Really not enough to make we want to reiterate

The end result is the theory agrees with scales work.
Hence it is fine to use 1/4" breathers on suzukis, if not all vehicles as the change is so low.

EDIT:Adding more discription
EDIT2:Adding bit more info

[Scales]

WHAT.... THE ..... FUCK!>?!?!!



I simply thought about it in a physical way and how much things would expand and contract vs volume of air, and deemed it negligible enough for a 1/4' hose. I compared it to a person breathing with a solid steel lung, it wouldnt be a lot!

oh that, and 90% of breathers on bigger fourbies use that pissant water filter hose thats like 1/8'

But that... is... maaaad.
if thats real math.... im impressed.

[jdk81]

Well I get sick of miss information spammed around.

Intuition indicated the volume and pressure drop would be low, and calcs confirmed it.

If I am going to argue, I may as well back it up with theory.

[Scales]

well done man, thanks for backing the theory. i like it. good to have piece of mind too.

[jdk81]

And the concern about plumbing it into the air box.

Testing on a landcruiser yields a pre-air cleaner pressure of 31.5cm H2O
The air pressure at intake was at high rpm, on a landcruiser, I would imagine a suzuki at mid rpm would have a lower pressure in the air box (considering we have a snorkel fitted).

So connecting the breather lines up to the air box is also fine, as the pressures are still relatively low.

1m of water (above the diff)
Assuming 31" tyres = 15.5" +1m = (15.5*25.4/1000)+1 = 1.4m
So this is a 1.4m deep hole, I have had mine sierra about 1.6m deep.

I havent tested to see how much pressure diff seals can withstand, I would imagine the selastic is fine, its the seal on the pinion and shafts which is the concern.
So 1m+ .31m = the equivalent of the diffs under 1.3m of water (above the diffs).
So this is equivalent of us driving into water 1.7m deep.

Having the diff and gearbox breathers plumbed into the air intake means we combust the hydrocarbon emissions.
We are reducing emissions people didnt consider, hence we are saving the environment.

I suspect the slight pressure difference wont really affect things much. If your diff doesnt leak when parked, itll probably be fine.
However, we cant always guarantee the condition of our diff seals, no matter how we vent them (1/2" pipe or 1/4" pipe, vented to atm, or plumbed to air box, or stock vents). So it you drive through deep water, consider inspecting the diff oil anyway.

We are only reducing the risk of giving them a gutfull of water, we cant guarantee anything.

[atari4x4]

nice number crunching thanks for taking the time to clear it up.

[SierraDan]

Scales wrote:

SierraDan wrote:

It'd have to be oiled though...

Sweet job man. My fuel filters have done me good.

Nope, shes a dry one. nothing stopping ya from giving it a squirt of filter oil if you were that way inclined. im happy with it the way it is, oil=dirt in my eyes and its not sucking constantly so yeah.

Sorry, i was commenting on the comment made about it being like a K&N so it would help repel water. If it were oiled maybe yes. Dry.. its just a filter. I run one too, does the job better than the factory ones

[Scales]

yeah i get ya, i thought of oiling it. but id rather keep it dry and clean rather than wet and muddy. like its just been proven with the airflow. the air filter isnt really "on duty" its just to stop bugs getting in really. shit you could use a cigarette filter and it'd do the same thing just as well. (in fact i seriously considered doing that, but liked the bling of the little red fella)

[Scales]

quick update on this.

Had the system fitted for ages now, still going great guns. no water issues.

Have since ran my gearbox and t-case breather lines to the SAME hose also, with no cross-contamination issues or water ingress. so thats 4 parts breathing on 1 hose now. all sweet.


So there you have it folks!
cheers.

[Jezza86]

jdk81 wrote:

We are reducing emissions people didnt consider, hence we are saving the environment.

diff breathers as an environmental control. i like it. will totaly offset the addtional emmisions from a 1.8!

[Wolf]

Which part of the setup is being sugested to use 1/4. The bit on yhe diff, or the line to the breather?

[Jezza86]

i put 1/2" id on the breather and put some thick fuel line with a od of 1/2" inside the 1/2" id line
then i hose clamped and silasticed the shit out of it

[Scales]

Wolf the smaller dia hose (either 3/16 1/4, your choice) is the main line running to the breather point. The 1/2in is the size required to squeeze over the diff nipples once you take the existing breather covers off.

You can see the brass adaptor I made to accomodate the change in size pretty clearly in the photos.

[greenzook89]

Scales this was pretty much the exact idea I copied my diff breathers off, and they are still going great

[albie200]

Good read....Over here in nz we use airbed pumps and hook up both diffs,gearbox and transfer also sometimes the distributor, helps create a positive pressure to keep the water out. Only about 1-2 psi, all the comp guys run it... As we have alot of mud..

[scorpydude]

jdk81 wrote:

Diff volume calcs.

For interest sakes air volume is = to diff oil volume, as diff oil is approx 1/2 way up the diff.
Temp of air whilst hot is assumed to be 328Kelvin, temp of cool diff will be assumed to be 288 Kelvin, to give us an extreme example (60 Degrees C hot, 15 Degrees C cold).

...snip...

Well done jdk81. We need more of this.

[jake84]

wow lots of info
next month ill be putting my breather kit on
is there a kit i can buy like an arb kit

so one way or another ill have to tap the bung hole to fit the breather plug ?

[Scales]

Kits won't work. Hose is wrong size ID for the nipples. Transfer is only one that needs to be tapped. It's easy to do.

[Wolf]

How did you get the metal bit off

[Scales]

What metal bit? The nipple on the transfer case? It's just an interference fit fitting. Just use a pair of vice grips and twist/work it out. You'll destroy the fitting in the process.

[Wolf]

The one on the diff the cap thing

[Scales]

Pair of pliers mate. Or a screwdriver lever it off. They just pop on and off

[jake84]

im thinking ill heads over to my mates work shop and get me a pair of the arb breather kits any one got them and what you think

[missmyljdaze]

jake84 wrote:

im thinking ill heads over to my mates work shop and get me a pair of the arb breather kits any one got them and what you think

I am pretty sure "Scales" pointed out earlier, that the kits that ARB etc sell are not suitable for the 'zooks as the hoses and stuff are the wrong size.

Everything you need to make a decent breather kit is "off the shelf" at any decent engineering supply shop and super - ripco - auto type shop.

roughly speaking, all you are doing is:

- remove the breather caps from the axle tubes and gearbox.

- finding the correct size hose for a good push-on fit for the metal breather tubes, and suitably sized clamps.

- tap a thread into the transfer case to suit a barb tailed fitting that matches the size hose you are using.

- attach hoses to all the fittings and run them all individually to one point high up, and hook them into generic plastic fuel filters.
or....daisy chain the hoses together into one line that leads to your high mounted fuel filter.
[last time I did this years ago, I ran the final hose into the carby air cleaner.]

- secure all the hoses and the filter so they dont hang loose, but leave enough slack hose over the axles, so your hektik flex doesnt tear the hoses out.


A few of the blokes here have "been there - done that", and made thier own.

Either do a search, or ask nicely for someone to point you to a relevant build thread, and you will have a shopping list of whats needed before you crawl under your zook with the pliers.

stephen