Rigorous air filter comparison test

"Steve" > wrote in message
...
> Daniel J. Stern wrote:
>
>> On Tue, 4 Jan 2005, Steve wrote:
>>
>>
>>>Daniel J. Stern wrote:
>>>
>>>
>>>>http://home.usadatanet.net/~jbplock/ISO5011/SPICER.htm
>>>>Interesting stuff. Just look how well that K&N did at stopping dirt!
>>
>>
>>>The rate at which they added dirt to the air flow is an unbelievable 9.8
>>>GRAMS per minute! Its hard to imagine that anything short of a 9+-liter
>>>turbo-diesel in a front-end loader working at the bottom of an open pit
>>>mine in the desert would ever see that kind of dirt ingestion rate. The
>>>problem with that sort of rate is that it doesn't just accelerate the
>>>test, as intended, it also overwhelms the ability of any passive
>>>electrostatic filter being tested to maintain its electrostatic charge.
>>>Each dirt particle that hits an electrostatic filter immediately
>>>neutralizes some of the filter's electrostatic charge, and air has to
>>>flow over the fibers again for a while to re-ionize them. Too high a
>>>dirt flow rate, and the filter never ionizes at all. My concern is that
>>>this kind of accelerated testing unfairly handicaps the oiled cotton
>>>filters, because they rely on electrostatic charge build-up in order to
>>>work.
>>
>>
>> I don't believe in the K&N magic, but let's say I did and you're right.
>> Ever drive through an extremely dusty area? A concrete construction zone,
>> for instance, or a windstorm in a dusty area? I surely have, and if what
>> you say is true, I'm more glad than ever that I don't use K&Ns.
>>
>> DS
>
> And good reason not to use them in such an area.
>
> On the other hand, do you believe that any measurable damage would happen
> to an engine just from driving through a single construction zone even
> WITHOUT an air filter?

Yes. depending on the time exposed and the abrasiveness of the dust then
substantial damage could occur in a short time scale.


>
> I think people that make a big deal out of feeding an engine ultra-clean
> air are chasing the wrong red herring. Dirt in the intake air is rarely
> the life-limiting factor for any internal combustion engine other than an
> off-road diesel earthmover.
>

A road engine on a damp day will injest clean air regardless. However,
following a lorry carrying sand without an element could well cause damage
within a few minutes.
As far as ultimate cleanliness is concerned, I would tend to agree with you.
But I was roundly condemned when I suggested that it is perfectly
permissible to wash and reuse elements by people who suggested that some
dust would somehow get past the pores after this and get through to damage
the engine. Like you, I am pragmatic and realistic about what it takes to
make a lump of metal continue to tick, because I own and run very many of
them. Given the choice however, I would use elements with the best
filtration efficiency or at least use the original equipment element model.
However, any element is better than none.

Huw

AZGuy wrote:
> On Mon, 3 Jan 2005 17:38:14 -0500, "Daniel J. Stern"
> > wrote:
>
>
>>On Mon, 3 Jan 2005, Steve W. wrote:
>>
>>
>>>>http://home.usadatanet.net/~jbplock/ISO5011/SPICER.htm
>>>>Interesting stuff. Just look how well that K&N did at stopping dirt!
>>
>>>Yep, proves what I have thought all along, K&N SUCKS!
>>
>>Yep. The conspiracy theoristas are already hard at work attacking the
>>study. Good luck, since it was impeccably conducted.
>>
>
>
> Actually the study results for % efficiency are very similar to what
> was at one time posted on the K&N website (don't know if it still is).
> K&N did report that paper filters had a typical filtration efficiency
> of 98% and that K&N were about 96%. As presented, and with just that
> one bit of info (not all the other tests in SPICER.htm) they said that
> for the slight increase in dirt being passed, the 2% difference, you
> got the big benefits of increased airflow. I never bought it but on
> the surface it doesn't sound like you are losing a whole lot if your
> primary goal is the extra 2 to 4 hp you might get at wide open
> throttle. When you see all the other poor results you'd be nuts to
> use a K&N - but I"m sure that this study won't slow their sales down
> one bit.

The problem is that the restriction from the air filter is one of
the smallest factors. I recall someone measured the restriction
along the intake path of a Mazda, and the air filter had the
least restriction. The resonator contributed several times more
restriction than the filter.

Daniel J. Stern wrote:

> On Tue, 4 Jan 2005, N8N wrote:
>
>
>>Well, in my experience, I've never had a truly *BAD* German-made
>>product, which sadly, I can't say for domestic products. So buying
>>German does seem to give some amount of assurance that you are getting
>>at least an acceptable quality product.
>
>
> My experience differs. Everyone makes crap, all over the world. Some
> countries, to varying degrees, also make good stuff.
>
> My experience with German cars has been awful.
>
> DS

We're just going to have to agree to disagree on that one. I know where
you're coming from, but IME I've driven German cars that were well past
their "best before" date and had only what I consider to be a very
reasonable amount of problems.

nate

--
replace "fly" with "com" to reply.
http://home.comcast.net/~njnagel

Huw wrote:

>
>>I think people that make a big deal out of feeding an engine ultra-clean
>>air are chasing the wrong red herring. Dirt in the intake air is rarely
>>the life-limiting factor for any internal combustion engine other than an
>>off-road diesel earthmover.
>>
>
>
> A road engine on a damp day will injest clean air regardless. However,
> following a lorry carrying sand without an element could well cause damage
> within a few minutes.

IF the intake path actually allowed sand-sized grains in, yeah I could
see that.

But really, what is the difference between 96% filtration and 99% in
terms of ultimate engine life, and given that you stop the boulders in
any case?

> As far as ultimate cleanliness is concerned, I would tend to agree with you.
> But I was roundly condemned when I suggested that it is perfectly
> permissible to wash and reuse elements by people who suggested that some
> dust would somehow get past the pores after this and get through to damage
> the engine. Like you, I am pragmatic and realistic about what it takes to
> make a lump of metal continue to tick, because I own and run very many of
> them. Given the choice however, I would use elements with the best
> filtration efficiency or at least use the original equipment element model.
> However, any element is better than none.
>

Absolutely agreed. My comments are geared more toward people who seem to
have a terror of talc-sized dust getting past a filter and want
semiconductor fab-room clean air for an engine that makes carbon grit as
a NORMAL PART of its operating process.

< When you see all the other poor results you'd be nuts to
> use a K&N - but I"m sure that this study won't slow their sales down
> one bit.

It's like the morons who pay several hundreds of dollars for speaker wire;
there's one born every minute.

"Steve" > wrote in message
...
> Huw wrote:
>
>>
>>>I think people that make a big deal out of feeding an engine ultra-clean
>>>air are chasing the wrong red herring. Dirt in the intake air is rarely
>>>the life-limiting factor for any internal combustion engine other than an
>>>off-road diesel earthmover.
>>>
>>
>>
>> A road engine on a damp day will injest clean air regardless. However,
>> following a lorry carrying sand without an element could well cause
>> damage within a few minutes.
>
> IF the intake path actually allowed sand-sized grains in, yeah I could see
> that.
>
> But really, what is the difference between 96% filtration and 99% in terms
> of ultimate engine life, and given that you stop the boulders in any case?
>
>> As far as ultimate cleanliness is concerned, I would tend to agree with
>> you. But I was roundly condemned when I suggested that it is perfectly
>> permissible to wash and reuse elements by people who suggested that some
>> dust would somehow get past the pores after this and get through to
>> damage the engine. Like you, I am pragmatic and realistic about what it
>> takes to make a lump of metal continue to tick, because I own and run
>> very many of them. Given the choice however, I would use elements with
>> the best filtration efficiency or at least use the original equipment
>> element model. However, any element is better than none.
>>
>
> Absolutely agreed. My comments are geared more toward people who seem to
> have a terror of talc-sized dust getting past a filter and want
> semiconductor fab-room clean air for an engine that makes carbon grit as a
> NORMAL PART of its operating process.
>

Not only that but modern diesels push a proportion of that hard carbon grit
back into the clean air inlet system. It's called EGR or exhaust gas
recirculation.

Huw

"Daniel J. Stern" > wrote in message
n.umich.edu...
> On Tue, 4 Jan 2005, N8N wrote:
>
>> Well, in my experience, I've never had a truly *BAD* German-made
>> product, which sadly, I can't say for domestic products. So buying
>> German does seem to give some amount of assurance that you are getting
>> at least an acceptable quality product.
>
> My experience differs. Everyone makes crap, all over the world. Some
> countries, to varying degrees, also make good stuff.
>
> My experience with German cars has been awful.

Late 80's and early 90's vw & Audi cars had some issues,
but for the most part, for decades, German cars are pretty
good designs, I have a 928 with over 200,000 miles, and it
still does what it should (well, it's getting new driveline bearings
now, but c'mon, its got a ****load of miles on it.) and I have a
Mercedes 300sd with 236,000 miles, and it drives like it
had a tenth as many on it.

You just have to pick the right ones, just like anything,
go price a carburetor for a 80's Honda, and talk about
design.

Bernard

"Bernard Farquart" > wrote in message
news:RZ1Dd.26135$_62.16730@trnddc01...
>
> "Daniel J. Stern" > wrote in message
> n.umich.edu...
>> On Tue, 4 Jan 2005, N8N wrote:
>>
>>> Well, in my experience, I've never had a truly *BAD* German-made
>>> product, which sadly, I can't say for domestic products. So buying
>>> German does seem to give some amount of assurance that you are getting
>>> at least an acceptable quality product.
>>
>> My experience differs. Everyone makes crap, all over the world. Some
>> countries, to varying degrees, also make good stuff.
>>
>> My experience with German cars has been awful.
>
> Late 80's and early 90's vw & Audi cars had some issues,
> but for the most part, for decades, German cars are pretty
> good designs, I have a 928 with over 200,000 miles, and it
> still does what it should (well, it's getting new driveline bearings
> now, but c'mon, its got a ****load of miles on it.) and I have a
> Mercedes 300sd with 236,000 miles, and it drives like it
> had a tenth as many on it.
>
> You just have to pick the right ones, just like anything,
> go price a carburetor for a 80's Honda, and talk about
> design.
>
> Bernard
>

I too have had nothing but good luck with VW.... an early 90's VW with
280,000km of relatively troublefree driving and now a 2002 VW.

The 2002 TDI has done 80,000 km with only a single lightbulb burning
out!!!!!

In rec.autos.tech Huw > wrote:

> "Steve" > wrote in message
> ...
> > Huw wrote:
> >
> >>
> >>>I think people that make a big deal out of feeding an engine ultra-clean
> >>>air are chasing the wrong red herring. Dirt in the intake air is rarely
> >>>the life-limiting factor for any internal combustion engine other than an
> >>>off-road diesel earthmover.
> >>>
> >>
> >>
> >> A road engine on a damp day will injest clean air regardless. However,
> >> following a lorry carrying sand without an element could well cause
> >> damage within a few minutes.
> >
> > IF the intake path actually allowed sand-sized grains in, yeah I could see
> > that.
> >
> > But really, what is the difference between 96% filtration and 99% in terms
> > of ultimate engine life, and given that you stop the boulders in any case?
> >
> >> As far as ultimate cleanliness is concerned, I would tend to agree with
> >> you. But I was roundly condemned when I suggested that it is perfectly
> >> permissible to wash and reuse elements by people who suggested that some
> >> dust would somehow get past the pores after this and get through to
> >> damage the engine. Like you, I am pragmatic and realistic about what it
> >> takes to make a lump of metal continue to tick, because I own and run
> >> very many of them. Given the choice however, I would use elements with
> >> the best filtration efficiency or at least use the original equipment
> >> element model. However, any element is better than none.
> >>
> >
> > Absolutely agreed. My comments are geared more toward people who seem to
> > have a terror of talc-sized dust getting past a filter and want
> > semiconductor fab-room clean air for an engine that makes carbon grit as a
> > NORMAL PART of its operating process.
> >

> Not only that but modern diesels push a proportion of that hard carbon grit
> back into the clean air inlet system. It's called EGR or exhaust gas
> recirculation.

> Huw



All we need now is an internet test of EGR valves. For most people
though the main thing is to change your cars air filter every once in
awhile. Brand is meaningless in these situations...