It is currently Thu Nov 21, 2019 12:58 pm
Board index » Talking About Stuff » Good Tech



Post new topic Reply to topic  [ 129 posts ]  Go to page Previous  1, 2, 3, 4, 5  Next
Author Message

Offline
User avatar

Joined: Sun Jul 04, 2010 10:09 pm
Posts: 302
Location: Dungowan

Post Posted: Sat Aug 24, 2013 10:55 pm 
Reply with quote Top  
http://www.aulro.com/afvb/technical-chatter/50650-air-filter-tests-finally.html

Interesting read, from someone who can back it up, on paper vs k&n......

 Profile  

Offline

Joined: Tue Jan 08, 2013 4:52 pm
Posts: 99
Vehicle: 93 Vitara -itty bitty lift

Post Posted: Sun Sep 29, 2013 1:49 pm 
Reply with quote Top  
know this is a bit of a grave dig but i though it might interest some folks
a youtube vid of a couple of cars on the dyno with pods and stock air filters
https://www.youtube.com/watch?v=PAIxeQUSg-Q

 Profile  

Offline
az supporter
az supporter
User avatar

Joined: Wed Sep 11, 2013 8:07 pm
Posts: 230
Vehicle: 92 wt soft top sierra

Post Posted: Tue Oct 01, 2013 5:36 pm 
Reply with quote Top  
Gwagensteve wrote:
There seems to be some many myths about air filters it's hard to know where to start, but here's some basic truths.

The task of an air filter is to remove harmful particles from the inlet air.

A filter is a filter and not a sieve. ALL filters filter more efficiently the dirtier they are (so long as they fit and are used in the right application). Just read that again.

ALL filters filter more efficiently the dirtier they are. Right up until the point they choke the engine. That means they are filtering so well they are actually stopping the air molecules from reaching the engine.

Every time you open the airbox of your engine you shorten the life of the engine. Industrial machinery (and even landcruisers) run a tell tale light to tell the operator when to change the filter based on pressure drop between each side of the filter. when the light lights, THAT's when you change the filter. You're actually harming the motor by changing the filter before there is a measurable pressure drop across the filter, and that's because you let dust into the inlet tract.

Every time you service your air filter, you reduce its filtration efficiency.

Foam and cotton gauze air filters don't filter as well as the stock paper filter. When they are really dirty, they might filter as well as a new paper filter in the same application.

Car manufacturers employ hundreds of engineers and have lots of money to throw around. Their engineers know stuff. They will fit the smallest, lightest and therefore cheapest air filter that provides the minimum required air filtration for the car and it's intended use. That means for a passenger car, a much smaller and lighter filter than for a 4WD. It also means it's false economy to fit a smaller lighter filter than the car came with unless you aren't interested in how long the engine lasts.

The air filter element is very rarely the source of power loss in an inlet tract. It's most often the diameter and path of the piping to and from the element.

Foam and oiled gauze filters generally have a smaller surface area than a convoluted paper filter. That means there is less surface area to trap dirt, meaning they clog more quickly.

OEM Air filter housings are designed to work with a paper filter. Most of the debris is designed to fall away from the filter, either by centrifugal force or gravity. Most filter housings then have a small hole or trap that actually lets this dust fall out of the housing. Oiled filters trap all this dirt, making the filter clog even quicker and preventing the airbox from working properly.

The particles that will wear out your engine are too small to see. If you can see dust in your inlet tract, your filtration is worse than terrible. Bear this in mind when you hold up a oiled gauze filter to the light. You can see pinpricks of light through them when new and clean.

If you think your air filter is a power restriction, you need a larger element and a larger airbox, not a filter with less surface area and a less efficient filter medium.

What is used in (certain forms of) racing is not applicable for road or recreational 4WD use. In a race car, if the engine rebuild interval is short, the air filtration becomes progressively less important. Two strokes that run for hours require just enough filtration to prevent the engine wearing out before it's operating parameters wear it out.

However, an engine that's expected to last 200,000km will require significantly better filtration than a race engine that has to last 1000km.

Additionally, as I touched on, use plays a huge part. An LS motor in a commodore uses a small, flat filter. An LS motor in a chev truck uses a huge flat filter. an LS motor in a desert race buggy (often) uses a UMP filter or a donaldson - a huge centrifugal filter that wouldn't fit under the bonnet of a road car, however, many people are happy to reduce the filtration effectiveness of their stock airbox with a "free flowing" filter.

There's a fair amount of science in filter selection. Paper filters are still considered the industry standard for filtration effectiveness.

If you want to make more power via your filter, fit a larger filter, not a smaller one.

Sorry if this seems like an arrogant rant, but there are plenty of people out there that are still buying oiled gauze and foam filters believing the marketing hype that they are doing something good for their motor (often because that's what "race teams use." The science (and logic) doesn't support this. You will never, ever, find any independent scientific data from the manufacturers of any of these filters indicating they filter as well or better than paper, but enormous lettering on the box about how many HP you will gain. It's a con.

Some context:

I've destroyed motors from poor filter selection (foam). I've also dynoed motors in cars with modified inlet pipe diameters, and with different filter sizes. I run a 1980's Hi-ace van filter in my Sierra, which is an almost direct copy of a Donaldson cyclopac. It's very well designed. I leave it alone- I haven't opened it since I fitted it over 12 months ago. It runs a paper filter.

Steve.



I back what steve said all the way, i just learnt all that stuff at stage 2 diesel fitting tafe.

 Profile  

Offline

Joined: Mon May 16, 2011 7:33 pm
Posts: 684
Location: Brinkworth, England

Post Posted: Wed Oct 30, 2013 10:58 pm 
Reply with quote Top  
I ran a K&N element on my road bike. My first engine (with stock filter) ran well for 174k miles, the second with the K&N ran well for 80k miles. The filter was serviced every 8000 miles using the proper K&N oil and there was a noticable drop off in performance when the filter needed cleaning. There was often a noticable film of very fine dust in the airbox after the filter. I would never a K&N in an off-roader, just hold a new one up to the light - you can see how bad a filter it is.

 Profile WWW  

Offline
Platinum Supporter
Platinum Supporter
User avatar

Joined: Tue Dec 06, 2011 10:00 am
Posts: 2154
Location: Nhulunbuy 0880
Vehicle: 2010 jimny

Post Posted: Wed Nov 06, 2013 3:44 pm 
Reply with quote Top  
electrostatic precipitates are made up from stainless wires that are electrified.
i can stick my fingers between the rows of wires. i am bigger than a bit of dust.
they still remove alumina dust from air flows as well as a bag house would as long as the power is on.

in a similar principal oil soaked filters work if they are oiled . the light passing factor doesnt actually mean anything because the foam filter is relying on oil capture rather than producing a filter cake on the filter surface as would happen in a paper filter. in saying that, the oil capture becomes less efficient at lower particle size (and mass) as the particle may avoid the oiled surfaces and travel with the air mass through the filter. particles avoiding contact with the oil will pass. this is because the low mass makes the particle more evasive, avoiding the collision with the fine oil barrier that protects your engine.
reusing filters risks damage from improper cleaning. even proper cleaning causes minute damage and this causes a change in the void volume. this in turn creates selective pathways where less surface area of exposed oil is available to capture particles.
IMO the optimum filtration method would be to use a precleaner, then a oilef filter to remove oversize, and a paper to cake and filter the <2.5pm materiel

 Profile WWW  

Offline

Joined: Mon May 16, 2011 7:33 pm
Posts: 684
Location: Brinkworth, England

Post Posted: Wed Nov 06, 2013 10:52 pm 
Reply with quote Top  
If you hold it up to the light you can see how big the holes in it are, the oil only clings to the surface of the fibres. Any particle smaller than the size of the hole will pass through if it doesn't hit the side.

 Profile WWW  

Offline
User avatar

Joined: Tue Sep 15, 2009 12:00 am
Posts: 4268
Location: Eyre Peninsula

Post Posted: Thu Nov 07, 2013 8:39 am 
Reply with quote Top  
IF your really tight on the amount of oil used, yes.

 Profile  

Offline
Platinum Supporter
Platinum Supporter
User avatar

Joined: Tue Dec 06, 2011 10:00 am
Posts: 2154
Location: Nhulunbuy 0880
Vehicle: 2010 jimny

Post Posted: Thu Nov 07, 2013 12:16 pm 
Reply with quote Top  
Rhinoman wrote:
If you hold it up to the light you can see how big the holes in it are, the oil only clings to the surface of the fibres. Any particle smaller than the size of the hole will pass through if it doesn't hit the side.


nearly. while foam and cotton filters do allow the passing of less than 2 micron dust, the 'hole' size is larger than 10 microns. the air borne pm10 dust is attracted to the oiled surface. the pm 2.5 and lower meterial is also attracted to the oiled surface, but not enough to pull it out of the air flow effectively.

 Profile WWW  

Offline
User avatar

Joined: Tue Sep 15, 2009 12:00 am
Posts: 4268
Location: Eyre Peninsula

Post Posted: Thu Nov 07, 2013 12:38 pm 
Reply with quote Top  
Not sure, a large airfilter, that has a slow inlet volume, rather than a small that has a high iltet volume, will trap far greater, big is the key.

 Profile  

Offline
Platinum Supporter
Platinum Supporter
User avatar

Joined: Tue Dec 06, 2011 10:00 am
Posts: 2154
Location: Nhulunbuy 0880
Vehicle: 2010 jimny

Post Posted: Thu Nov 07, 2013 2:01 pm 
Reply with quote Top  
the key is to minimize flow velocity. double the number of pathways (size of filtration area) and you have half the flow velocity, minimizing pressure drop.
the larger area can catch more dust before this pressure drop is a issue.

 Profile WWW  

Offline
User avatar

Joined: Mon Dec 26, 2011 2:41 pm
Posts: 398
Location: Frankston

Post Posted: Mon Nov 25, 2013 7:11 pm 
Reply with quote Top  
I wonder how my pod filter is going to go this weekend :D
I am stirring the pot

 Profile  

Offline
az supporter
az supporter
User avatar

Joined: Sat Feb 04, 2012 7:41 pm
Posts: 1083
Location: Oberon, NSW
Vehicle: Drover pickup turk

Post Posted: Sun Jan 12, 2014 8:39 pm 
Reply with quote Top  
Hey Steve,

Does this like it would be any good?

Image

Image

Image

Image

Image

Image

Image

Image

_________________
Quote:
I like the tuna here

 Profile  

Offline
User avatar

Joined: Thu Feb 26, 2009 11:00 pm
Posts: 11261
Location: Melbourne

Post Posted: Sun Jan 12, 2014 8:59 pm 
Reply with quote Top  
That looks to be a nicely designed filter. In comparison to the Hiace filter it's only lacking the diffuser that encourages the centrifugal action. I reckon I'd run it.

Steve.

 Profile  

Offline
az supporter
az supporter
User avatar

Joined: Sat Feb 04, 2012 7:41 pm
Posts: 1083
Location: Oberon, NSW
Vehicle: Drover pickup turk

Post Posted: Mon Jan 13, 2014 9:43 am 
Reply with quote Top  
Same filter Part No. (Ryco) as a Hicace. http://www.rycofilters.com.au/catalogue ... part/A1215

_________________
Quote:
I like the tuna here

 Profile  

Offline
az supporter
az supporter
User avatar

Joined: Thu May 27, 2010 12:31 pm
Posts: 832
Location: Melbourne

Post Posted: Mon Jan 13, 2014 7:01 pm 
Reply with quote Top  
look a lot like the one I have. but mine had the diffuser, maybe you can get a different filter that will fit with a diffuser

viewtopic.php?f=5&t=34568&p=768462&hilit=mitsubishi#p768462

 Profile  

Offline
az supporter
az supporter
User avatar

Joined: Sat Feb 04, 2012 7:41 pm
Posts: 1083
Location: Oberon, NSW
Vehicle: Drover pickup turk

Post Posted: Mon Jan 13, 2014 7:41 pm 
Reply with quote Top  
Yea this one came from a Mitsubishi van (Delica) aswell.

_________________
Quote:
I like the tuna here

 Profile  

Offline

Joined: Fri Feb 14, 2014 8:07 pm
Posts: 132
Vehicle: 1999 Suzuki Jimny JLX

Post Posted: Thu Jan 08, 2015 3:03 pm 
Reply with quote Top  
Sorry to drag up an old thread but I have read through this a few times and have thouroughly enjoyed it. I have a K&N panel filter in my Jimny and after reading this I went down to Repco and ordered a Ryco paper filter.
Another interesting thing... I've been driving my Dad's 2010 Subaru Forester 2.5L petrol and have noticed that it doesn't feel as nimble as it use to before. I decided to check the air filter and I found the problem. The filter was black and was clogged with leaves, sticks, stones, bugs and the odd butterfly. On the opposite side of the air filter where the engine draws its clean air, the airbox was absolutely spotless and there wasn't even a spec of dust. This was a stock Denso paper air filter.
Also when I worked at Caterpillar on trucks, they just had a no frills giant cylindrical paper air filter or two.

Ray

 Profile  

Offline
User avatar

Joined: Tue Sep 15, 2009 12:00 am
Posts: 4268
Location: Eyre Peninsula

Post Posted: Sat Jan 10, 2015 9:06 am 
Reply with quote Top  
Ray, like radiators, go the biggest possible, mostly things are built to a price, ie small as possible. I changed my radiator to a custom job, huge, had to cut the car a bit to get it in, near 3 times the stock suzi volume, I run thermos only, very seldom come on, airfilters, same deal, bigger is better, small filter, means air is roaring past the medium, this means a loss of power, big big filter, very slow movement across medium.

 Profile  

Offline
az supporter
az supporter
User avatar

Joined: Fri Feb 04, 2011 11:25 pm
Posts: 9347
Location: Newcastle
Vehicle: G13BB Jimny

Post Posted: Sat Jan 10, 2015 12:12 pm 
Reply with quote Top  
Weird

_________________
mlm

 Profile  

Offline
User avatar

Joined: Tue Sep 15, 2009 12:00 am
Posts: 4268
Location: Eyre Peninsula

Post Posted: Sat Jan 10, 2015 7:51 pm 
Reply with quote Top  
?? what is weird.

_________________
Bad decisions make good stories.

 Profile  

Offline

Joined: Fri Feb 14, 2014 8:07 pm
Posts: 132
Vehicle: 1999 Suzuki Jimny JLX

Post Posted: Sat Jan 10, 2015 9:54 pm 
Reply with quote Top  
I agree SuziBlu, the air filter on the Subaru seems way too small but it does its job very well. What do you think about the stock Jimny filter size? If its possible I'd like to put a bigger filter/airbox combo on but I don't think there would be enough space anyway.

Ray

 Profile  

Offline
User avatar

Joined: Thu Feb 26, 2009 11:00 pm
Posts: 11261
Location: Melbourne

Post Posted: Sun Jan 11, 2015 10:11 am 
Reply with quote Top  
Ray, filters are sized for the air they are required to flow, the level of filtration required, and the service interval expected.
The Jimny airbox is effectively a modified baleno airbox, and isn't designed for off road work. if it was, it would look more like a Sierra airbox (not that they are all that well designed, but they were designed for offroad work.) the Jimny filter was designed for circa 20k service intervals in road use, just like a car.

The Sierra filter has a much bigger air filter area, so it can operate for longer in a dirty environment before requiring service.
It also uses centrifugal force to prevent heavy/large particles sticking to the filter. I don't like manufacture of the Sierra box, (as in they often don't seal very well) but the engineering principles are sound.

If you are concerned about the short service interval of the Jimny filter, the best option would be to fit a snorkel and a Donaldson cyclonic pre cleaner. This will take out most of the dust that loads up the stock filter.

I too doubt there is enough space for a filter suited to severe service under a Jimny bonnet.

Steve.

 Profile  

Offline
User avatar

Joined: Thu Feb 26, 2009 11:00 pm
Posts: 11261
Location: Melbourne

Post Posted: Sun Jan 11, 2015 10:15 am 
Reply with quote Top  
My experience with Subaru filters is that they do require reasonably frequent replacement. I don't consider this unusual for modern cars though - a small, light, and therefore cheap filter that requires replacement once a year is a more cost effective and easier to engineer than a heavy "severe duty" filtration system that might only need changing every two years.

Horses for courses.

Of course, some experts then remove that small filter and replace it with one that barely filters at all in the name of added horsepower which they then service every two months to ensure it never gets dirty enough to filter properly.

 Profile  

Offline
User avatar

Joined: Fri Oct 29, 2010 2:23 pm
Posts: 5666
Location: Northcliffe, W.A.
Vehicle: LJs, Sierra, Jimny, Swift.

Post Posted: Sun Jan 11, 2015 12:25 pm 
Reply with quote Top  
Jimny airboxes are totally garbage. My air filter looks like it's being force fed dirt, that's never been a problem with any other cars

Suzuki say for dusty road use to inspect the filter every 2500kms, I'd say that's about right.

 Profile  

Offline
User avatar

Joined: Thu Feb 26, 2009 11:00 pm
Posts: 11261
Location: Melbourne

Post Posted: Sun Jan 11, 2015 1:15 pm 
Reply with quote Top  
That's common for flat panel filters IMHO.

Steve.

 Profile  

Offline

Joined: Fri Feb 14, 2014 8:07 pm
Posts: 132
Vehicle: 1999 Suzuki Jimny JLX

Post Posted: Mon Jan 12, 2015 9:50 pm 
Reply with quote Top  
I see, thanks Steve! Since reading this thread I've been looking at airboxes in other cars and can see that the Jimny airbox is tiny. I've been thinking of ideas to try and maybe mount a small pre cleaner under the bonnet as I'm not keen on a snorkel but like before, there probably isn't enough room. Its interesting how something so important such as air filters can be overlooked so easily.

Ray

 Profile  

Offline
User avatar

Joined: Thu Feb 26, 2009 11:00 pm
Posts: 11261
Location: Melbourne

Post Posted: Tue Jan 13, 2015 4:15 pm 
Reply with quote Top  
I think the Jimny filter is perfectly fine for the use most Jimmy's are put to - and that's the key thing - filter choice is a cost and use assessment by the manufacturer.

I agree it looks tough to fit anything larger under bonnet.

If you regularly travel in very dusty conditions and are concerned about engine longevity, I would definitely run a snorkel and donaldson pre cleaner.

I'd also consider a magnehelic gauge to monitor differential pressure, or a "pop off" indicator as used by heavy equipment. These will pop to red when the air filter presents restriction over a predetermined level, but they do require opening the bonnet to check. a magnehelic gauge could be installed in the dash and monitored real time. My Gwagen had a pop-off indicator standard.

Only ever open the air box when the gauge/indicator tells you to.
do not blow out/dust/or tap the filter clean. remove it and replace it with a new filter.

That's the only way to ensure the minimum silica enters the engine. Every time you open the air box of an engine you shorten its life.

Also consider silica enters the engine via the dipstick, oil cap, PCV hose it it doesn't seal perfectly.

Problem is, a Jimny motor is likely to be worn out before any of these steps make a measurable difference... but if you want to know, that's how to do it.

 Profile  

Offline
User avatar

Joined: Wed Feb 06, 2013 8:54 pm
Posts: 1447
Vehicle: 91 Tin Top

Post Posted: Sat Jan 17, 2015 9:01 pm 
Reply with quote Top  
sideways wrote:
Jimny airboxes are totally garbage. My air filter looks like it's being force fed dirt, that's never been a problem with any other cars

Suzuki say for dusty road use to inspect the filter every 2500kms, I'd say that's about right.



This is a Jimny airbox (fed by normal snorkel with no precleaner) after about 800km of dirt roads, then copped really heavy rain on the highway for about the last 100km from home.
The rain being sucked into the snorkel turned all the dust into mud and made this.

Image



OEM filter after 30,000km, yes that is bugs stuck in the groves.

Image



A decent precleaner would make a huge difference.

 Profile  

Offline
az supporter
az supporter
User avatar

Joined: Fri Jul 22, 2011 11:39 am
Posts: 1009
Location: Melbourne
Vehicle: Suzuki Jimny 2009

Post Posted: Tue Jan 20, 2015 8:48 pm 
Reply with quote Top  
I did over 8,000km with about 2,000 on dirt roads with a pre-cleaner fitted and I didn't replace my air filter for another 6 months after that. The only time I drew in any significant dust was when I left the engine running while on the side of the road while a road train went in the other direction. I should have turned the engine off as the pre-cleaner needs a good air flow through it to work.

Mike

 Profile  

Offline
User avatar

Joined: Wed Feb 06, 2013 8:54 pm
Posts: 1447
Vehicle: 91 Tin Top

Post Posted: Tue Jan 20, 2015 10:19 pm 
Reply with quote Top  
Thanks for the confirmation Mike.
I cleaned the airbox and filter (sorry for cleaning my air filter Steve :( ) only 2 days before I left, the dirt in that pic was from just from that one trip.


Just wanted to show how much stuff gets shoved down a normal snorkel.

 Profile  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 129 posts ]  Go to page Previous  1, 2, 3, 4, 5  Next

Jump to:  


Who is online

Users browsing this forum: No registered users and 40 guests

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum
Untitled Document


Untitled Document


Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group :: Style based on FI Subice by phpBBservice.nl :: All times are UTC + 10 hours