[DeTomaso] Data for K&N filters
Guido deTomaso
guido_detomaso at prodigy.net
Sun Nov 20 18:27:26 EST 2016
Years ago I was taught there are two broad categories of air filters, barrier filters and depth filters.
A paper element is a good example of a barrier filter, there are passages through the filter media of a known diameter, nothing bigger can get through. The barrier tends itself to be thin, but of a high surface area.
A foam air filter like you'd see on a dirt bike is a depth filter. The passages or pore diameter is greater than the size of particles you'd like to have pass through, but the odds are most of the particles will hit some oily fiber and stick to it. As the name implies, a depth filter tends to be thick, but with a low surface area.
The advantage of the barrier filter is nothing gets through above a certain particle size. A downside is they can't hold / tolerate a huge amount of dust before they clog and become restrictive. Also they don't tolerate getting wet.
A depth filter can hold a lot of dust before it becomes ineffective, tolerates water, but does not provide that absolute pore size to protect the engine.
So ... the K&N strikes me as the best / worst of both worlds. It's a very thin depth filter with a high surface area. Low restriction at the cost of letting some particles through. Once every sticky cotton strand has some dust stuck to it, I believe they continue to work as an ersatz barrier filter - the spaces between the stuck on dust limit the size of what gets through. I believe this is why they are popular in off-road, they sort of keep working after others would clog.
While not a fan I've got applications where there's no paper element of the correct shape, so use a K&N. It's kinda fun to use the special soap and wash out the dust with water, but alarming how thin the cotton can get in spots with use and repeated washing. Being thorough with the red oil means it slowly soaks all the cotton, then drips out at the bottom for few days.
For a dirt bike there's no way I'd consider replacing a foam unit with a K&N, the frequent cleaning would just be too much compared to the ease of washing a foam element.
But for a road-going vehicle, only paper if I have a choice.
Or so it seems to me, I could be wrong.
GD
From: Garth Rodericks via DeTomaso <detomaso at server.detomasolist.com>
To: DeTomaso Mail List <detomaso at server.detomasolist.com>
Sent: Saturday, November 19, 2016 12:50 PM
Subject: [DeTomaso] Data for K&N filters
Years ago I recall reading a magazine dyno test (Hot Rod? Car Craft? or
one of those) of a typical round K&N filter against a comparable paper
filter, but I can't find it online. I recall they found the K&N didn't
provide any additional horsepower against a stock filter when new,
however after a limited time/miles (simulated by adding dust to the
filters on the dyno) they found the K&N provided a horsepower increase
over the paper filters as their flow capacity was greatly reduced
pretty quickly as they began to collect dirt. But, they also provided
more protection for your engine! Again, this is just from memory, and
I have no interest in promoting K&N. I do have a K&N filter on my
Pantera and have thought about just stocking up on inexpensive paper
filters and changing them more regularly as the K&N it seems to get
dirty quite quickly and it's a PITA to clean.
Here are some other resources:
[1]http://www.knfilters.com/filter_facts.htm - Yes, this is K&N's
website, but there are some links to other resources (which are
favorable toward K&N of course)
[2]https://www.bobistheoilguy.com/airfilter/airtest3.htm - Bob is the
oil guy filter test results - a good read.
I couldn't find any other resources online worth reading other than
Dan's post from David Vizard's book "How to Build Horsepower" (Thanks
for the link Julian).
[3]https://books.google.es/books?id=OAw1GDB0kN0C&printsec=frontcover&hl
=es#v=onepage&q&f=false
Everything else online is just miscellaneous drivel on other car forums
with people arguing back and forth.
Cheers!
Garth
#4033
References
1. http://www.knfilters.com/filter_facts.htm
2. https://www.bobistheoilguy.com/airfilter/airtest3.htm
3. https://books.google.es/books?id=OAw1GDB0kN0C&printsec=frontcover&hl=es#v=onepage&q&f=false
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-------------- next part --------------
Years ago I was taught there are two broad categories of air filters,
barrier filters and depth filters.
A paper element is a good example of a barrier filter, there are
passages through the filter media of a known diameter, nothing bigger
can get through. The barrier tends itself to be thin, but of a high
surface area.
A foam air filter like you'd see on a dirt bike is a depth filter. The
passages or pore diameter is greater than the size of particles you'd
like to have pass through, but the odds are most of the particles will
hit some oily fiber and stick to it. As the name implies, a depth
filter tends to be thick, but with a low surface area.
The advantage of the barrier filter is nothing gets through above a
certain particle size. A downside is they can't hold / tolerate a huge
amount of dust before they clog and become restrictive. Also they
don't tolerate getting wet.
A depth filter can hold a lot of dust before it becomes ineffective,
tolerates water, but does not provide that absolute pore size to
protect the engine.
So ... the K&N strikes me as the best / worst of both worlds. It's a
very thin depth filter with a high surface area. Low restriction at
the cost of letting some particles through. Once every sticky cotton
strand has some dust stuck to it, I believe they continue to work as an
ersatz barrier filter - the spaces between the stuck on dust limit the
size of what gets through. I believe this is why they are popular in
off-road, they sort of keep working after others would clog.
While not a fan I've got applications where there's no paper element of
the correct shape, so use a K&N. It's kinda fun to use the special
soap and wash out the dust with water, but alarming how thin the cotton
can get in spots with use and repeated washing. Being thorough with
the red oil means it slowly soaks all the cotton, then drips out at the
bottom for few days.
For a dirt bike there's no way I'd consider replacing a foam unit with
a K&N, the frequent cleaning would just be too much compared to the
ease of washing a foam element.
But for a road-going vehicle, only paper if I have a choice.
Or so it seems to me, I could be wrong.
GD
__________________________________________________________________
From: Garth Rodericks via DeTomaso <detomaso at server.detomasolist.com>
To: DeTomaso Mail List <detomaso at server.detomasolist.com>
Sent: Saturday, November 19, 2016 12:50 PM
Subject: [DeTomaso] Data for K&N filters
Years ago I recall reading a magazine dyno test (Hot Rod? Car Craft?
or
one of those) of a typical round K&N filter against a comparable
paper
filter, but I can't find it online. I recall they found the K&N
didn't
provide any additional horsepower against a stock filter when new,
however after a limited time/miles (simulated by adding dust to the
filters on the dyno) they found the K&N provided a horsepower
increase
over the paper filters as their flow capacity was greatly reduced
pretty quickly as they began to collect dirt. But, they also provided
more protection for your engine! Again, this is just from memory,
and
I have no interest in promoting K&N. I do have a K&N filter on my
Pantera and have thought about just stocking up on inexpensive paper
filters and changing them more regularly as the K&N it seems to get
dirty quite quickly and it's a PITA to clean.
Here are some other resources:
[1][1]http://www.knfilters.com/filter_facts.htm - Yes, this is K&N's
website, but there are some links to other resources (which are
favorable toward K&N of course)
[2][2]https://www.bobistheoilguy.com/airfilter/airtest3.htm - Bob is
the
oil guy filter test results - a good read.
I couldn't find any other resources online worth reading other than
Dan's post from David Vizard's book "How to Build Horsepower" (Thanks
for the link Julian).
[3][3]https://books.google.es/books?id=OAw1GDB0kN0C&printsec=frontcover
&hl
=es#v=onepage&q&f=false
Everything else online is just miscellaneous drivel on other car
forums
with people arguing back and forth.
Cheers!
Garth
#4033
References
1. [4]http://www.knfilters.com/filter_facts.htm
2. [5]https://www.bobistheoilguy.com/airfilter/airtest3.htm
3.
[6]https://books.google.es/books?id=OAw1GDB0kN0C&printsec=frontcover&hl
=es#v=onepage&q&f=false
_______________________________________________
Detomaso Email List is not managed by POCA
Posted emails must not exceed 1.5 Megabytes
DeTomaso mailing list
[7]DeTomaso at server.detomasolist.com
[8]http://server.detomasolist.com/mailman/listinfo/detomaso
To manage your subscription (change email address, unsubscribe, etc.)
use the links above.
Members who post to this list grant license to the list to forward any
message posted here to all past, current, or future members of the
list. They also grant the list owner permission to maintain an archive
or approve the archiving of list messages.
References
1. http://www.knfilters.com/filter_facts.htm
2. https://www.bobistheoilguy.com/airfilter/airtest3.htm
3. https://books.google.es/books?id=OAw1GDB0kN0C&printsec=frontcover&hl
4. http://www.knfilters.com/filter_facts.htm
5. https://www.bobistheoilguy.com/airfilter/airtest3.htm
6. https://books.google.es/books?id=OAw1GDB0kN0C&printsec=frontcover&hl=es#v=onepage&q&f=false
7. mailto:DeTomaso at server.detomasolist.com
8. http://server.detomasolist.com/mailman/listinfo/detomaso
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