Snorkel: Air Ram or Pre Cleaner?

[Ben Up North]

Which would be better for dust?
It seems pretty logical to me that the pre cleaner would be better than the air ram for dust assuming the air ram didn't have a sock.


Which is better in (heavy - when we get it it generally thumps down) rain

It also seems logical to me that the pre cleaner would be better than the air ram for rain ingress.


So.. if using a sock on the air ram, is there any noticeable restriction in air flow?

How often do they need cleaning in 'normal' use (i.e. not outback dust)?
How do you clean them?


Is anyone using/used a pre cleaner? Do you ever need to empty it in 'normal' use? Do yo still use it?



Thanks!

 

[Kevin]

I tried the oiled socks but they clogged up pretty quickly in the outback and needed cleaning daily. They may help if un-oiled. I think the cyclonic pre-cleaners would be good e.g. https://www.donaldsontoolbox.com.au/files/8213/8084/0061/13ENG025_TopSpin_HD_PreCleaner-Oct2013.pdf

 

[Ben Up North]

Yeah, that's what I meant by pre cleaner. Thinking of getting one as I'm worried about the rain destroying the air filter

 

[Beachworm]

air ram

I've been doing a bit of research on snorkels and the ram effect is next to negligible under 100Kph so it doesn't make too much difference whether the snorkel faces forwards or backwards.

The primary purpose of a snorkel is to prevent water ingress and some designs now incorporate a water trap with a drain valve where conditions are such that some water entry is inevitable.

The secondary purpose is to place the air intake in such a way as to minimise the amount of dust entering the intake. The higher the better though very fine dust is still going to be a problem and that's the kind that will block the air filter. This is a problem when travelling in convoy. After a day in a convoy of a dozen or so cars on dry dusty tracks recently, my relatively new air filter had to be vacuumed as a stop-gap measure. A rear-facing intake on a snorkel doesn't fix that problem either as a low pressure spot is created at the entrance to the snorkel and dust gets sucked in just as much as it would with an air ram.

There is no filter, apart from a cyclonic filter that will remove dust without clogging so I agree with Kevin. Apart from looking daggy and bulky, a cyclonic filter is the best option. There is always the option of using a sock and washing it out frequently.

You could take a cordless vacuum and vacuum the main air filter element every time you stop for a break. :rotfl:

 

[Kevin]

You could take a cordless vacuum and vacuum the main air filter element every time you stop for a break.

This is what I do in the evenings :iconwink: Bang the filter on a tree trunk a few times then vacuum with a 18V Ryobi cordless hand vacuum.

 

[Beachworm]

cyclonic filters

If you want a good, though biased explanation of cyclonic versus ram, see the following link https://www.4wdworld.com.au/Airflow-Snorkels---everything-you-wanted-to-know.html

 

[El_Freddo]

There's a few issues there. And I felt the article didn't really explain anything in the end anyway... I'll admit I read it a few nights ago and can't be bothered reading it again. Anyway:

To have any true ram air effect the scoop would need to be a much larger diametre to create a decent high pressure event in the intake. It'd have to be something like 30cm sq to have any great effect.

Also scooping water during rain is a falicy if you've got a decent snorkel - mine is a safari unit and built into the scoop is several drains in the back of the scoop. The idea is the rain droplets can't change direction as quick as air due to their weight. These droplets then hit the back of the scoop of the snorkel then run out via the drains at the back of the scoop at the top of the snorkel. I've not had a wet filter in the heaviest of rain with only very little water in the bottom of the air box - that I don't worry about.

As for the cyclonic device - I'd probably only use it when needed and have the scoop on every other time. I've heard good things from a few people that have used them.

Cheers

Bennie

 

[duncanm]

Cyclonics are absolutely awesome when you need them.


I was passenger in a 4wd in a Simpson desert sandstorm and the sand was literally raining out the bottom of it.


With a standard intake, you would have to stop and wait it out.


Whether you need to keep driving in such conditions is another matter.

 

[Beachworm]

i'd love to know if anyone has put a snorkel on an SH Forester. Now that I've done my breather extensions both front and rear that should be my next project but I haven't been able to find anything on line that details how to fit one to the SH model. The shape of the front guard makes it unlikely that the Pajero unit used on the SG would fit. Is anyone able to share some ideas with me?

 

[scalman]

that pajero unit fits my gen outback ?anyone know what people put on those outbacks?
and thats serious problem if that rain will come inside tube. i mean i dont wanna that happen. what about have air sucking hole looking away and not in front ? saw some people do that on some diy snorkels. i mean no rain problem and less dust as well.

i mean not this kind

but that

if that style works then should be no rain problems anymore is it ?
..unless you go backwards and rain goes inside still haha

 

[Ben Up North]

what about have air sucking hole looking away and not in front ? saw some people do that on some diy snorkels. i mean no rain problem and less dust as well.

I'm pretty sure that even backwards rain gets drawn in. I'm positive it will in the tropics here when it's absolutely belting down. Sometimes you can't see more than 10 or 20 metres ahead - which makes driving in the rain interesting mainly because of the idiots on the road that don't slow down going around roundabouts.

 

[scalman]

as with most mods and such we all need different stuff depends where we live. sadly most ppl just uses what some use for their countries. like i dont need most stuff that australia needs or US and such. so yh depends from our weather best thing would be to have one for any weather is it ? in russia what flies high is mostly mud and not water or dust haha. so against mud facing rear is better i guess.

 

[Beachworm]

Rear facing openings create negative pressure, not a lot, but enough to reduce air flow and suck dust and perhaps water into the snorkel. All good snorkel systems have a design that catches small amounts of water that may enter. This is the concern with many home-made snorkels. They do not account for water entry.

 

[duncanm]

As noted above, a good snorkel design will have a couple of sharp bends and drainage to do away with large droplets of water. The principle is exactly the same as a cyclonic or Dyson vac, accelerate the air around a bend fast enough that the particles you want to remove fling out of the airstream and hit the walls, ala:

 

[Ben Up North]

So I'm norrowing down the choices..
And I'm doing it on the cheap so a Donaldson is out of the choices.


Anyone using this type of precleaner?

The advantage as I see it is that this one is self cleaning (the dirt just drops out) and not quite as ugly as this:

Edit2: It looks like this one is self cleaning too, so I guess it comes down to how well they work (compared to each other)

Whatever I put on, will probably stay on. Main reason for general use is to stop the airfilter getting damp/wet (there are no drain holes in my snorkel)

 

[Ben Up North]

As noted above, a good snorkel design will have a couple of sharp bends and drainage to do away with large droplets of water. The principle is exactly the same as a cyclonic or Dyson vac, accelerate the air around a bend fast enough that the particles you want to remove fling out of the airstream and hit the walls, ala:

Ahh..
Well the head of my snorkel looks spretty much exactly like the one you pictured.

So perhaps a cycloinc filter is not needed for general use.

The air ram style is certainly the most common around here, where every second 4wd you see has one (and a 4"lift)

 

[Kevin]

A normal snorkel head is fine if you're not doing lots of outback stuff in the bulldust or, especially, in convoy which I find is the worst for dust build up in the air filter.

 

[scalman]

You can make with homemade what you want it to be . all those water catching / removing spaces looks just simple things to do. If you need it thou. Ppl just put sock on it from dust if going in caravans and stuff.