Pre filter for K&N ???
Melting Slicks
Joined: Aug 2004
Posts: 3,003
Likes: 89
From: Indy IN
Paper filters have an issue with collapsing if you get them loaded with water, and that is why K&N type filters are used in off road racing, where if you have to cross a stream you could get water into the filter and that would be a bad thing.
Beyond that, any filter will work for a day or two, and then you rebuild the engine after the race anyway. If you take time to look at the data in the SAE test, the restriction of the K&N was actually worse after the filter became loaded with the same amount of dirt that was in the paper filter. It took less total dirt to block the K&N filter than it did the paper filter and the paper filter actually had less restriction after that. In the referenced test, the K&N “plugged up” nearly 3 times faster, passed 18 times more dirt than the AC filter.
I haven't been fording any streams in the Vette, so I'll stick with paper.
Last edited by Solofast; Jan 28, 2010 at 07:59 AM.
Premium Supporting Vendor
Joined: Aug 2001
Posts: 5,364
Likes: 38
From: King George VA
I use and recommend: AMSOIL Ea Air Filter
C5 part EAA83
I'm clearly biased, but I used to run K&N and I stopped after I came to believe that the higher air flow of wetted gauze came at the expense of filtration. Several years ago my motor was way down on power. Had it taken to a dyno to try to evaluate why and while I never really was sure the cause, my leak down was on the order of 8-10% whereas a new crate motor is typically around 3-5%. In testing, we also swapped the filter from the K&N to a paper filter during the dyno runs and it gained 2 Hp. Probably well within the tolerance of the dyno, but between the poor leakdown and the lack of impressive dyno gains with the K&N, I swapped to the EAA filters and have been using them since. However, no concrete dyno run in several years so can't say for certain whether my leakdown is any better or worse than it was before. As a final point, I was also very leery of oil from the intake filter on the MAF. With EAA filter I don't have to worry about that anymore either.
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Last edited by C66 Racing; Jan 28, 2010 at 08:51 PM.
Melting Slicks
Joined: Aug 2004
Posts: 3,003
Likes: 89
From: Indy IN
I use and recommend: AMSOIL Ea Air Filter
C5 part EAA83
C5 part EAA83
Thanks for the tip.
Last edited by Solofast; Jan 29, 2010 at 11:22 AM.
Premium Supporting Vendor
Joined: Aug 2001
Posts: 5,364
Likes: 38
From: King George VA
That looks pretty interesting. I wasn't aware of the Ea filter. Sounds like something that I will definately try. It's 4x as expensive as a typical paper filter, but it lasts longer and, more importantly filters better. Looks like it's worth a shot. The air filter is the first line of defense in terms of maintaining an engine...
Thanks for the tip.
Thanks for the tip.
Race Director
Joined: Jan 2006
Posts: 10,554
Likes: 33
From: Not on either liberal coast.
DONALDSON is the original developer of the "Blackwing" oil gauze (synthetic) filter. The marketing rights to that product were later sold out to SLP.
DONALDSON/SLP is therefore a competitor of K&N.
DONALDSON/SLP is therefore a competitor of K&N.
Last edited by hotwheels57; Jan 30, 2010 at 11:17 AM.
Burning Brakes
Joined: Oct 2004
Posts: 931
Likes: 35
From: Rowlett, Texas
There is a pretty neat way to do your own evaluation of a filter.
We did this all the time on dirt bikes to help trap some of the fine dust that went right through the oiled foam filters.
We spread a thin film of heavy grease on the intake boot between the filter and the carb, particularly where the boot elbow'd, or changed direction. The dirt would be captured in the grease film as it banged into the side of the intake boot trying to change direction.
So, just coat the inside top of the "cobra" duct on your Vette, and maybe the accordion boot as well, run a few thousand miles and see how dirty it gets.
You can also coat the outside of the throttle body and the blade, but on the Vette that might be misleading due to all the nasty PCV oil being drawn through the engine adjacent to the throttle blade.
DG
We did this all the time on dirt bikes to help trap some of the fine dust that went right through the oiled foam filters.
We spread a thin film of heavy grease on the intake boot between the filter and the carb, particularly where the boot elbow'd, or changed direction. The dirt would be captured in the grease film as it banged into the side of the intake boot trying to change direction.
So, just coat the inside top of the "cobra" duct on your Vette, and maybe the accordion boot as well, run a few thousand miles and see how dirty it gets.
You can also coat the outside of the throttle body and the blade, but on the Vette that might be misleading due to all the nasty PCV oil being drawn through the engine adjacent to the throttle blade.
DG
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Melting Slicks
Joined: Aug 2004
Posts: 3,003
Likes: 89
From: Indy IN
Donaldson knows their stuff on air filtration. We are having huge success using some of their stuff on some turbine engines that we have been working on. We need to move huge amounts of air at a very low pressure drop, and they are claiming less than a 4 inch of water drop for the stuff that we are doing. I'll be putting in the Amsoil filter when I bring the car out in the spring...
Racer
Joined: Dec 2008
Posts: 469
Likes: 0
From: Lindenhurst New York
Just thought I would add my 2 cents....... I truly do not believe the K & N style filters filter quite as well as the paper filters, however for a street car Im sure the K & N is more than adequate. I also have a wrangler and in the jeep world any none paper filter is a no no because of all the dirt and such the jeep will be exposed to is bad. On a corvette or my supercharged truck for example, a K & N would filter most of the contaminants so I wouldn't worry to much, its not like you plan on driving through dirt or water do you? On another note, I know a few turbo cars and ITB setups where people use no filter at all..... just food for thought.
Safety Car
Joined: Sep 2000
Posts: 3,572
Likes: 420
From: Taildragers rule! USA1
K&N = snake oil
Burning Brakes
Joined: Jul 2004
Posts: 768
Likes: 6
From: Newport Beach, Southern California
Just thought I would add my 2 cents....... I truly do not believe the K & N style filters filter quite as well as the paper filters, however for a street car Im sure the K & N is more than adequate. I also have a wrangler and in the jeep world any none paper filter is a no no because of all the dirt and such the jeep will be exposed to is bad. On a corvette or my supercharged truck for example, a K & N would filter most of the contaminants so I wouldn't worry to much, its not like you plan on driving through dirt or water do you? On another note, I know a few turbo cars and ITB setups where people use no filter at all..... just food for thought.
