Air filters
10-29-2015, 09:41 AM
#1
Safety Car
Thread Starter
10-29-2015, 09:09 PM
#2
Melting Slicks
Richard,
The reason that K&N won't telly you how good their filters are, or how small a particle they filter out is because their filters are junk. They flow a lot air when they are fresh, but they don't filter well, and it doesn't take much dirt to clog them up. Once they get some dirt in them they don't filter at all. All K&N will say is that they filter out something like 97% of the particles in the air, but a good filter takes out 99.93%, or something like that, so, compared to a good filter the K&N is passing about 30 times as much junk.
There was an article where they were tested against the SAE spec and it turned out that a good paper filter was far more effective at keeping dirt out of your engine than a oiled filter like a K&N.
Here's a link to that test report.. http://www.nicoclub.com/archives/kn-vs-oem-filter.html
Amsoil has a high tech filter that has only slightly more restriction than the K&N, but has much better filtration and much longer life. It's not the same filter that is listed as the Amsoil filter in the above test. They don't make them for the C5 but I got a couple when they did. It is based on technology developed by Davidson filters and it's a pretty amazing piece.
A K&N is better than nothing, and if you're looking for something for a race car that isn't used much but if you're driving on the street or have a motor that you really want to protect then get a real filter and don't waste your money on a K&N.
About the only place you'd want a filter like that is if you have a lot of water in the air that would mess up a paper filter, and that's why they use them in off road racing.
The reason that K&N won't telly you how good their filters are, or how small a particle they filter out is because their filters are junk. They flow a lot air when they are fresh, but they don't filter well, and it doesn't take much dirt to clog them up. Once they get some dirt in them they don't filter at all. All K&N will say is that they filter out something like 97% of the particles in the air, but a good filter takes out 99.93%, or something like that, so, compared to a good filter the K&N is passing about 30 times as much junk.
There was an article where they were tested against the SAE spec and it turned out that a good paper filter was far more effective at keeping dirt out of your engine than a oiled filter like a K&N.
Here's a link to that test report.. http://www.nicoclub.com/archives/kn-vs-oem-filter.html
Amsoil has a high tech filter that has only slightly more restriction than the K&N, but has much better filtration and much longer life. It's not the same filter that is listed as the Amsoil filter in the above test. They don't make them for the C5 but I got a couple when they did. It is based on technology developed by Davidson filters and it's a pretty amazing piece.
A K&N is better than nothing, and if you're looking for something for a race car that isn't used much but if you're driving on the street or have a motor that you really want to protect then get a real filter and don't waste your money on a K&N.
About the only place you'd want a filter like that is if you have a lot of water in the air that would mess up a paper filter, and that's why they use them in off road racing.
10-29-2015, 11:00 PM
#3
Race Director
Richard,
The reason that K&N won't telly you how good their filters are, or how small a particle they filter out is because their filters are junk. They flow a lot air when they are fresh, but they don't filter well, and it doesn't take much dirt to clog them up. Once they get some dirt in them they don't filter at all. All K&N will say is that they filter out something like 97% of the particles in the air, but a good filter takes out 99.93%, or something like that, so, compared to a good filter the K&N is passing about 30 times as much junk.
There was an article where they were tested against the SAE spec and it turned out that a good paper filter was far more effective at keeping dirt out of your engine than a oiled filter like a K&N.
Here's a link to that test report.. http://www.nicoclub.com/archives/kn-vs-oem-filter.html
Amsoil has a high tech filter that has only slightly more restriction than the K&N, but has much better filtration and much longer life. It's not the same filter that is listed as the Amsoil filter in the above test. They don't make them for the C5 but I got a couple when they did. It is based on technology developed by Davidson filters and it's a pretty amazing piece.
A K&N is better than nothing, and if you're looking for something for a race car that isn't used much but if you're driving on the street or have a motor that you really want to protect then get a real filter and don't waste your money on a K&N.
About the only place you'd want a filter like that is if you have a lot of water in the air that would mess up a paper filter, and that's why they use them in off road racing.
The reason that K&N won't telly you how good their filters are, or how small a particle they filter out is because their filters are junk. They flow a lot air when they are fresh, but they don't filter well, and it doesn't take much dirt to clog them up. Once they get some dirt in them they don't filter at all. All K&N will say is that they filter out something like 97% of the particles in the air, but a good filter takes out 99.93%, or something like that, so, compared to a good filter the K&N is passing about 30 times as much junk.
There was an article where they were tested against the SAE spec and it turned out that a good paper filter was far more effective at keeping dirt out of your engine than a oiled filter like a K&N.
Here's a link to that test report.. http://www.nicoclub.com/archives/kn-vs-oem-filter.html
Amsoil has a high tech filter that has only slightly more restriction than the K&N, but has much better filtration and much longer life. It's not the same filter that is listed as the Amsoil filter in the above test. They don't make them for the C5 but I got a couple when they did. It is based on technology developed by Davidson filters and it's a pretty amazing piece.
A K&N is better than nothing, and if you're looking for something for a race car that isn't used much but if you're driving on the street or have a motor that you really want to protect then get a real filter and don't waste your money on a K&N.
About the only place you'd want a filter like that is if you have a lot of water in the air that would mess up a paper filter, and that's why they use them in off road racing.
I use K&N and clean/oil it every 6 months or so. I change oil per the dic indicator (about every 5k miles) My Blackstone test is excellent. So what did I miss here?
What does a c6z oem filter cost these days at a dealer?
10-30-2015, 05:41 AM
#4
Melting Slicks
Froggy,
If you're willing do clean it that frequently then it's probably ok, but most folks don't. If you live in a high dust environment, then you'd see a lot of silicon in your analysis, but if you're not showing that you're ok.
There was also a guy that I saw was doing regular oil sample testing and used one for a couple of months and saw his analysis results shoot up with high silicon when he switched from paper to K&N.
If you plan on not tearing an engine down for 100k miles then I wouldn't use one. If you want some extra track performance then use it at the track and take it out for the street.
The only time filter restriction makes any difference at all is at WOT and you aren't using that on the street very often anyway.
If you're willing do clean it that frequently then it's probably ok, but most folks don't. If you live in a high dust environment, then you'd see a lot of silicon in your analysis, but if you're not showing that you're ok.
There was also a guy that I saw was doing regular oil sample testing and used one for a couple of months and saw his analysis results shoot up with high silicon when he switched from paper to K&N.
If you plan on not tearing an engine down for 100k miles then I wouldn't use one. If you want some extra track performance then use it at the track and take it out for the street.
The only time filter restriction makes any difference at all is at WOT and you aren't using that on the street very often anyway.
10-30-2015, 06:48 AM
#5
Safety Car
Thread Starter
There is very little transparency regarding oil and air filters. It's all about marketing hype. the data exists (as Solo has demonstrated) but it's not widely shared.
Richard Newton
Richard Newton
10-30-2015, 11:30 AM
#6
Melting Slicks
There is so much snake oil being pedaled in this part of the market that getting to the real facts are nearly impossible.
I'm not a fan boy of Amsoil in general, but they really had a great product with this new technology air filter and it didn't seem to sell all that well, which is unfortunate. I became aware of it through some aerospace connections I had with Davidson filters and when I looked into the product I was most impressed. It had low intake loss and it was very good at filtration and you could clean it out a couple of times before you pitched it, so it was decent in the economics even if it was more expensive up front.
K&N is one of the worst I terms of hiding their true performance and they sell it as "you can feel the power".. BS... all they do is make some more intake noise and that's supposed to make you think it's making more power...
For a race car that gets torn down on frequently it probably doesn't make much difference so long as you keep the big rocks out of the intake, but if you're trying to get 100k miles from and engine it's really important to have good filtration.
As Froggy is doing, regular oil analysis is probably a good way to track it, but most of us just change the filter on a regular (or not so regular) basis and keep on going. In that case you want the best filter you can get and that's the easy way to keep it healthy for a long time.
10-30-2015, 01:59 PM
#8
Race Director
When I am servicing the K&N (I wash it, let it air dry, reoil) I stick the oem paper in. I don't notice much difference if at all.
I have been know to clean the paper filter also (just knock most of the dirt out by rapping it on a tree). I only do this once or twice as I know I can't see all the dust clogging it up. I do, however, give it a test by just holding it up to the bright sun & see if it looks ok or not.
When I compete I want ZERO flow restriction & the K&N does that for me.
Also my yearly miles are about 5k and the coastal environment is not all that dusty for the most part.
Good discussion.
So what's a stock c6z filter go for? The c5z is pretty cheap. Is zr1 the same as c6z?
I have been know to clean the paper filter also (just knock most of the dirt out by rapping it on a tree). I only do this once or twice as I know I can't see all the dust clogging it up. I do, however, give it a test by just holding it up to the bright sun & see if it looks ok or not.
When I compete I want ZERO flow restriction & the K&N does that for me.
Also my yearly miles are about 5k and the coastal environment is not all that dusty for the most part.
Good discussion.
So what's a stock c6z filter go for? The c5z is pretty cheap. Is zr1 the same as c6z?
10-30-2015, 11:06 PM
#9
Melting Slicks
Member Since: Jul 2010
Location: Tacoma, Wa/Surprise, Az
Posts: 2,849
Received 193 Likes
on
166 Posts
When I am servicing the K&N (I wash it, let it air dry, reoil) I stick the oem paper in. I don't notice much difference if at all.
I have been know to clean the paper filter also (just knock most of the dirt out by rapping it on a tree). I only do this once or twice as I know I can't see all the dust clogging it up. I do, however, give it a test by just holding it up to the bright sun & see if it looks ok or not.
When I compete I want ZERO flow restriction & the K&N does that for me.
Also my yearly miles are about 5k and the coastal environment is not all that dusty for the most part.
Good discussion.
So what's a stock c6z filter go for? The c5z is pretty cheap. Is zr1 the same as c6z?
I have been know to clean the paper filter also (just knock most of the dirt out by rapping it on a tree). I only do this once or twice as I know I can't see all the dust clogging it up. I do, however, give it a test by just holding it up to the bright sun & see if it looks ok or not.
When I compete I want ZERO flow restriction & the K&N does that for me.
Also my yearly miles are about 5k and the coastal environment is not all that dusty for the most part.
Good discussion.
So what's a stock c6z filter go for? The c5z is pretty cheap. Is zr1 the same as c6z?
10-30-2015, 11:38 PM
#10
Race Director
About in the $160 rangr. They've merged the filters such that a filter for the LS3 is the same for the LS9. Since the ZR1 moves a lot more air than the LS3, the stock filter is good enough. I too am not a fan of K and N air filters, their Oil filters are supposed to be okay.
Thanks Mike good post. I am not a shill for K&N just work good for me, but if/when I get a zr1 I'll have to reexamine the whole thing.
Last edited by froggy47; 10-30-2015 at 11:40 PM.
10-31-2015, 11:17 AM
#12
Melting Slicks
Also look at the rubber around it and how it seals. A bad seal can make a good filter into junk. Softer sealing plastic seals better and is generally more expensive.
I would really like to see filter makers have to list their efficiency and dirt holding capacity. We have labels on our food that tells us what we are eating, but there is nothing that allows us to judge a product like this and that is unfortunate. You could be buying junk or you could be getting a good filter (as in the test above a "no name" generic filter was actually very good), you just never know.
You know that the OE filter is good at protecting your engine because GM has metrics that they test against and use to spec their filtration. When they are offering a long warranty the also know that they need a lot of capacity because most folks don't change their filters on a regular basis. But also expect a bit more restriction in an OE filter because they want to use tighter paper that passes less crap.
As an aside I was on the AMSOIL site and they sell some generic filters with their Ea technology, so if you are using generic style filters with a cone or round configuraion on a race car or have a different than stock airbox/inlet you may be able to use one of their filters and that is good stuff. The Amsoil Ea and the Donaldson Blue filters are really good technology, low restriction and high filtration is what you want.
10-31-2015, 10:53 PM
#15
Race Director
The best measure of a filter is surface area. The more pleats and the thicker the filter the lower the restriction and the more dirt it will hold. The other thing is how fine are the pores on the filter, and that is impossible to see with the naked eye, but the smaller the pores the better the filtration efficiency. The best filter has a huge area and small pores, but without test data you have nothing.
Also look at the rubber around it and how it seals. A bad seal can make a good filter into junk. Softer sealing plastic seals better and is generally more expensive.
I would really like to see filter makers have to list their efficiency and dirt holding capacity. We have labels on our food that tells us what we are eating, but there is nothing that allows us to judge a product like this and that is unfortunate. You could be buying junk or you could be getting a good filter (as in the test above a "no name" generic filter was actually very good), you just never know.
You know that the OE filter is good at protecting your engine because GM has metrics that they test against and use to spec their filtration. When they are offering a long warranty the also know that they need a lot of capacity because most folks don't change their filters on a regular basis. But also expect a bit more restriction in an OE filter because they want to use tighter paper that passes less crap.
As an aside I was on the AMSOIL site and they sell some generic filters with their Ea technology, so if you are using generic style filters with a cone or round configuraion on a race car or have a different than stock airbox/inlet you may be able to use one of their filters and that is good stuff. The Amsoil Ea and the Donaldson Blue filters are really good technology, low restriction and high filtration is what you want.
Also look at the rubber around it and how it seals. A bad seal can make a good filter into junk. Softer sealing plastic seals better and is generally more expensive.
I would really like to see filter makers have to list their efficiency and dirt holding capacity. We have labels on our food that tells us what we are eating, but there is nothing that allows us to judge a product like this and that is unfortunate. You could be buying junk or you could be getting a good filter (as in the test above a "no name" generic filter was actually very good), you just never know.
You know that the OE filter is good at protecting your engine because GM has metrics that they test against and use to spec their filtration. When they are offering a long warranty the also know that they need a lot of capacity because most folks don't change their filters on a regular basis. But also expect a bit more restriction in an OE filter because they want to use tighter paper that passes less crap.
As an aside I was on the AMSOIL site and they sell some generic filters with their Ea technology, so if you are using generic style filters with a cone or round configuraion on a race car or have a different than stock airbox/inlet you may be able to use one of their filters and that is good stuff. The Amsoil Ea and the Donaldson Blue filters are really good technology, low restriction and high filtration is what you want.
When we had the bad fires in the North County (lot's of ash in the air) a local Chevy dealer offered free air filter service (replacement) which I thought was a pretty cool PR thing to do. I have no idea how many they "gave away" (they also looked to sell other services of course, but no pressure).
You will not go wrong with oem (except maybe price) but they are not max flow once they load up with "dirt".
11-01-2015, 11:40 AM
#16
Melting Slicks
Coming from the drag racing world I read a few dyno tests between different filters. A K&N was tested against multiple paper filters, they all made withing 2-3 HP of each other.
Where the K&N was best is when the filter started to collect dirt, it flowed almost as good dirty as it did clean.
Hot Rod Magazine did a shootout years ago, I remember reading it. Although I can't find that article, here are excerpts from it.
http://www.v8buick.com/archive/index.php/t-219465.html
http://www.moparchat.com/forums/arch...p?t-70169.html
Advanced Flow Engineering (AFE) http://www.afefilters.com
Size: Magnum Flow 14X3
Price: $59.59 USD
Approximate Airflow Capacity: 3,122 CFM
Chassis Dyno: 251.1 hp @ 4300; 307.9 lb-ft @ 4250
Engine Dyno: 365.9 hp @ 4800; 444.8 lb-ft @ 3900
Holley http://www.holley.com
Size: Power Shot 14X3
Price: $39.99 USD
Approximate Airflow Capacity: 3,068 CFM
Chassis Dyno: 250.6 hp @ 4300; 308.7 lb-ft @ 4250
Engine Dyno: 367.2 hp @ 4800; 444.6 lb-ft @ 3900
K&N Engineering http://www.knfilters.com
Size: FilterCharger 14X3
Price: $69.93 USD
Approximate Airflow Capacity: 2,988 CFM
Chassis Dyno: 249.7 hp @ 4250; 308.6 lb-ft @ 4250
Engine Dyno: 368.7 hp @ 4900; 444.5 lb-ft @ 3900
Purolator Products http://www.pureoil.com
Size: 14X3 Premium Plus
Price: $5.99 USD (not a typo)
Approximate Airflow Capacity: 2,518 CFM
Chassis Dyno: 246.7 hp @ 4250; 305.6 lb-ft @ 4250
Engine Dyno: 368.7 hp @ 4900; 443.5 lb-ft @ 3900
Rush Performance Filters http://www.barrygrant.com
Size: Rush 14X3
Price: $44.30 USD
Approximate Airflow Capacity: 2,836 CFM
Chassis Dyno: 251.0 hp @ 4250; 311.0 lb-ft @ 4250
Engine Dyno: 368.5 hp @ 4700; 446.5 lb-ft @ 3800
I'm no professional engine builder. I'm not an engineer, so the following assumptions are based off of my own common sense (I'm not even much good at that):
For price, Purolator has the competition nailed. 6 BUCKS? Compaired to a 70 dollar K&N filter. I suppose some people are looking at price while others don't give a damn about it. I personally cannot and refuse to spend 70 dollars on a street driven air filter. Not to mention that from the 60-70 dollar filters that K&N and AFE offer to the 6 dollar one that I can grab around the corner, you are losing almost 3 hp. I'm not sure how much that bothers you guys. Again, for a street driven application, I don't mind. As far as airflow (CFM) goes, the following is the list from lowest to highest:
Purolator (2,518)
Rush (2,836)
K&N (2,988)
Holley (3,068)
AFE (3,122)
The AFE has them all, some by a small margin and others by a landslide. Now, for the power. I noticed that some of these air filters tended to change their peak output RPM. For those of you out there that are hardcore into it, this may have some sort of affect on you. I'll list off the highest HP and then the RPM because I'm not sure if its more important to you guys to achieve more HP at a higher RPM or a lower RPM (I'd assume you'd all cheer for low). These are all on the engine dyno because the factors of the chassis dyno are variable to your particular vehicle.
Purolator (368.7 @ 4900 RPM)
K&N (368.7 @ 4900 RPM)
Rush (368.5 @ 4700 RPM)
Holley (367.2 @ 4800 RPM)
AFE (365.9 @ 4800 RPM)
Now, the Purolator and the K&N run together as far as an engine dyno is concerned. But teh Rush is closing in at a close 368.5 (A miniscule .2 HP) but its peak HP is 200 RPM lower than the victors. Advantage? If I was running a nice, low biting stroker, I would opt for the Rush just to keep my RPM that much lower. Winner by choice of best HP capability, Rush.
Torque gets you off the line faster and gets your rolley polley @ss moving. So how did these filters fair?
Rush (446.5 @ 3800 RPM)
AFE (444.8 @ 3900 RPM)
Holley (444.6 @ 3900 RPM)
K&N (444.5 @ 3900 RPM)
Purolator (443.5 @ 3900 RPM)
The Rush has the highest output torque on the engine dyno. A small 2 lb-ft of torque but at 100 RPM less than its competitors. Not only does it put out more torque, it does it sooner. Winner: Rush.
Hot Rod claims that they could not make a proper judgement call based on the fact that the numbers were so close together that it could just be temperature difference. I disagree. I'd probably have to go with the Rush after thinking this through. But the numbers are above and the decision is up to you.
I wish I could dig up that test.
Where the K&N was best is when the filter started to collect dirt, it flowed almost as good dirty as it did clean.
Hot Rod Magazine did a shootout years ago, I remember reading it. Although I can't find that article, here are excerpts from it.
http://www.v8buick.com/archive/index.php/t-219465.html
http://www.moparchat.com/forums/arch...p?t-70169.html
Advanced Flow Engineering (AFE) http://www.afefilters.com
Size: Magnum Flow 14X3
Price: $59.59 USD
Approximate Airflow Capacity: 3,122 CFM
Chassis Dyno: 251.1 hp @ 4300; 307.9 lb-ft @ 4250
Engine Dyno: 365.9 hp @ 4800; 444.8 lb-ft @ 3900
Holley http://www.holley.com
Size: Power Shot 14X3
Price: $39.99 USD
Approximate Airflow Capacity: 3,068 CFM
Chassis Dyno: 250.6 hp @ 4300; 308.7 lb-ft @ 4250
Engine Dyno: 367.2 hp @ 4800; 444.6 lb-ft @ 3900
K&N Engineering http://www.knfilters.com
Size: FilterCharger 14X3
Price: $69.93 USD
Approximate Airflow Capacity: 2,988 CFM
Chassis Dyno: 249.7 hp @ 4250; 308.6 lb-ft @ 4250
Engine Dyno: 368.7 hp @ 4900; 444.5 lb-ft @ 3900
Purolator Products http://www.pureoil.com
Size: 14X3 Premium Plus
Price: $5.99 USD (not a typo)
Approximate Airflow Capacity: 2,518 CFM
Chassis Dyno: 246.7 hp @ 4250; 305.6 lb-ft @ 4250
Engine Dyno: 368.7 hp @ 4900; 443.5 lb-ft @ 3900
Rush Performance Filters http://www.barrygrant.com
Size: Rush 14X3
Price: $44.30 USD
Approximate Airflow Capacity: 2,836 CFM
Chassis Dyno: 251.0 hp @ 4250; 311.0 lb-ft @ 4250
Engine Dyno: 368.5 hp @ 4700; 446.5 lb-ft @ 3800
I'm no professional engine builder. I'm not an engineer, so the following assumptions are based off of my own common sense (I'm not even much good at that):
For price, Purolator has the competition nailed. 6 BUCKS? Compaired to a 70 dollar K&N filter. I suppose some people are looking at price while others don't give a damn about it. I personally cannot and refuse to spend 70 dollars on a street driven air filter. Not to mention that from the 60-70 dollar filters that K&N and AFE offer to the 6 dollar one that I can grab around the corner, you are losing almost 3 hp. I'm not sure how much that bothers you guys. Again, for a street driven application, I don't mind. As far as airflow (CFM) goes, the following is the list from lowest to highest:
Purolator (2,518)
Rush (2,836)
K&N (2,988)
Holley (3,068)
AFE (3,122)
The AFE has them all, some by a small margin and others by a landslide. Now, for the power. I noticed that some of these air filters tended to change their peak output RPM. For those of you out there that are hardcore into it, this may have some sort of affect on you. I'll list off the highest HP and then the RPM because I'm not sure if its more important to you guys to achieve more HP at a higher RPM or a lower RPM (I'd assume you'd all cheer for low). These are all on the engine dyno because the factors of the chassis dyno are variable to your particular vehicle.
Purolator (368.7 @ 4900 RPM)
K&N (368.7 @ 4900 RPM)
Rush (368.5 @ 4700 RPM)
Holley (367.2 @ 4800 RPM)
AFE (365.9 @ 4800 RPM)
Now, the Purolator and the K&N run together as far as an engine dyno is concerned. But teh Rush is closing in at a close 368.5 (A miniscule .2 HP) but its peak HP is 200 RPM lower than the victors. Advantage? If I was running a nice, low biting stroker, I would opt for the Rush just to keep my RPM that much lower. Winner by choice of best HP capability, Rush.
Torque gets you off the line faster and gets your rolley polley @ss moving. So how did these filters fair?
Rush (446.5 @ 3800 RPM)
AFE (444.8 @ 3900 RPM)
Holley (444.6 @ 3900 RPM)
K&N (444.5 @ 3900 RPM)
Purolator (443.5 @ 3900 RPM)
The Rush has the highest output torque on the engine dyno. A small 2 lb-ft of torque but at 100 RPM less than its competitors. Not only does it put out more torque, it does it sooner. Winner: Rush.
Hot Rod claims that they could not make a proper judgement call based on the fact that the numbers were so close together that it could just be temperature difference. I disagree. I'd probably have to go with the Rush after thinking this through. But the numbers are above and the decision is up to you.
I wish I could dig up that test.
Last edited by FASTFATBOY; 11-01-2015 at 11:41 AM.
11-01-2015, 12:51 PM
#18
Melting Slicks
Since we're on this subject, my car came with a Vararam that has a green filter.
I pulled it to clean it and it was filthy. I had an old K&N cleaning kit and used it.
Reckon it hurt anything?
I pulled it to clean it and it was filthy. I had an old K&N cleaning kit and used it.
Reckon it hurt anything?
11-01-2015, 02:59 PM
#19
Race Director
I don't know the green filters, but in either case, I doubt you hurt anything.
11-01-2015, 03:26 PM
#20
Melting Slicks