Mike
Well-Known Member
Here's a little bit for you to think over the next time you're servicing your vehicles.
K&N wants you to believe you're going to get a million miles of service out of their air filters. They remind you how much more air they flow and how you will get better mileage and more power.
Caveat emptor.
Yes, there will be more air flow with a K&N air filter than with a paper filter. But not a significant amount. Pressure drop across any filter is fairly negligible.
So how does that "magic" K&N filter achieve more flow? Well, when you think about how a filter works, it starts to become painfully obvious.
If we build an air filter from solid metal, one from paper and one from oiled cotton-gauze, the metal filter isn't going to flow much air. And the K&N filter will slightly edge the paper filter in terms of air flow. I can assemble a filter element from chicken wire that will out-flow anything else, mind.
But when we start looking at filtering ability, we start to see some differences that amount to something. That metal filter won't flow any air, but it is 100% effective at keeping contaminants out of your engine. The paper filter will work well at filtering contaminants. The K&N filter won't work as well in the beginning, will start to improve at some point, but will then start to lose ground again, when the material is loaded and starts to develop air channels. And my good, ol' chicken wire element will be doing a wonderful job of keeping out chickens, sea gulls, beer bottles and small children.
When I was still at the shop, my employer also owned a 3/8 mile dirt oval track. And, as you can imagine, we did a lot of engine work for racers at the track. The average racer is on a numbers hunt, when building an engine. Which naturally leads them to K&N's front door, because of all that additional air flow they think they are going to get. But when we would get the engines back in at the end of a season for a freshen, we were seeing dirt in the intake runners. So, we decided we would try using Outerwears, which really didn't seem to make much difference. Every year, we were touching up the bores and ordering another new set of pistons, to get things sealed back up again. And I was always harping at everyone to remember to clean their carbs each week. Idle circuits and high speed circuits were constantly plugging up with dirt.
A former employee from the machine shop sat down and very purposely built an engine for one of the classes at the track. And when we got down to air filter selection, he decided to apply a different method. He tried a 4" K&N air filter on the dyno. He then pulled the K&N and since he didn't have access to a 4" paper filter, he sealed two paper filters with silicone and ran that combination. No difference in the numbers. So that was the combination that went to the race track, where he ran circles around everyone else. The next day, instead of having a cotton-gauze air filter that could be cleaned and reinstalled, he was looking at replacing his paper filter combination. So, when week 2 rolled around, he had two, new paper filters, with an Outerwear. And suddenly, he was getting 3 weeks out of his paper filters. But the proof came at the end of the year, when he knocked the shortblock apart and saw he was going to be able to run that set of pistons for a second season.
Like I said, these will be fighting words to many. But let me tell you, I didn't fall off the turnip truck, just last night. Before you start telling me how much better K&N filters are, because of all the racer teams using them, let me remind you how those racers are constantly taking things apart to freshen them. Are you ready to take the engine in your significant other's car apart each Winter, so you can freshen it up? No? See the difference? And don't depend on a decal on the side of your favorite racer's car to "know" what products he is running. Pennzoil gave us plain, white, oil bottles. That way, no one knew what oil was getting poured into the engine. We were working with a local coil winder, looking for the best combination of materials and wraps. Once week we would have a clunky-looking Vertex coil on the car, but the next week it might be the same coil inside a Mallory cannister. You really have to be careful what those lying eyes and ears are trying to tell you.
A multi-time Pro Stock World Champion used our valve springs for years, but when the titanium springs started appearing on the market, he switched and used them. But he discovered he could still receive a contingency check by running our decals on the car, so that was the arrangement. Every year, his Christmas card to the shop would have a note inside, requesting a dozen contingency decals be mailed to the shop.
In ongoing oil analysis testing, we consistently saw high silicate content in the engine oil, when using the K&N elements. And we also saw snotty-running street cars, where K&N filter oil had been drawn into down stream air sensors and has fouled them. Just how much oil does a K&N air filter require? Too little and the filter becomes as useful as udders on a bowling ball. Too much oil and your street driver is suddenly running like trash.
For the cost of a paper element you can simply drop in and forget for a few thousand miles, the cotton-gauze filters are a wonderful and delightful waste of money. That are introducing unnecessary contaminants into your engine.
K&N wants you to believe you're going to get a million miles of service out of their air filters. They remind you how much more air they flow and how you will get better mileage and more power.
Caveat emptor.
Yes, there will be more air flow with a K&N air filter than with a paper filter. But not a significant amount. Pressure drop across any filter is fairly negligible.
So how does that "magic" K&N filter achieve more flow? Well, when you think about how a filter works, it starts to become painfully obvious.
If we build an air filter from solid metal, one from paper and one from oiled cotton-gauze, the metal filter isn't going to flow much air. And the K&N filter will slightly edge the paper filter in terms of air flow. I can assemble a filter element from chicken wire that will out-flow anything else, mind.
But when we start looking at filtering ability, we start to see some differences that amount to something. That metal filter won't flow any air, but it is 100% effective at keeping contaminants out of your engine. The paper filter will work well at filtering contaminants. The K&N filter won't work as well in the beginning, will start to improve at some point, but will then start to lose ground again, when the material is loaded and starts to develop air channels. And my good, ol' chicken wire element will be doing a wonderful job of keeping out chickens, sea gulls, beer bottles and small children.
When I was still at the shop, my employer also owned a 3/8 mile dirt oval track. And, as you can imagine, we did a lot of engine work for racers at the track. The average racer is on a numbers hunt, when building an engine. Which naturally leads them to K&N's front door, because of all that additional air flow they think they are going to get. But when we would get the engines back in at the end of a season for a freshen, we were seeing dirt in the intake runners. So, we decided we would try using Outerwears, which really didn't seem to make much difference. Every year, we were touching up the bores and ordering another new set of pistons, to get things sealed back up again. And I was always harping at everyone to remember to clean their carbs each week. Idle circuits and high speed circuits were constantly plugging up with dirt.
A former employee from the machine shop sat down and very purposely built an engine for one of the classes at the track. And when we got down to air filter selection, he decided to apply a different method. He tried a 4" K&N air filter on the dyno. He then pulled the K&N and since he didn't have access to a 4" paper filter, he sealed two paper filters with silicone and ran that combination. No difference in the numbers. So that was the combination that went to the race track, where he ran circles around everyone else. The next day, instead of having a cotton-gauze air filter that could be cleaned and reinstalled, he was looking at replacing his paper filter combination. So, when week 2 rolled around, he had two, new paper filters, with an Outerwear. And suddenly, he was getting 3 weeks out of his paper filters. But the proof came at the end of the year, when he knocked the shortblock apart and saw he was going to be able to run that set of pistons for a second season.
Like I said, these will be fighting words to many. But let me tell you, I didn't fall off the turnip truck, just last night. Before you start telling me how much better K&N filters are, because of all the racer teams using them, let me remind you how those racers are constantly taking things apart to freshen them. Are you ready to take the engine in your significant other's car apart each Winter, so you can freshen it up? No? See the difference? And don't depend on a decal on the side of your favorite racer's car to "know" what products he is running. Pennzoil gave us plain, white, oil bottles. That way, no one knew what oil was getting poured into the engine. We were working with a local coil winder, looking for the best combination of materials and wraps. Once week we would have a clunky-looking Vertex coil on the car, but the next week it might be the same coil inside a Mallory cannister. You really have to be careful what those lying eyes and ears are trying to tell you.
A multi-time Pro Stock World Champion used our valve springs for years, but when the titanium springs started appearing on the market, he switched and used them. But he discovered he could still receive a contingency check by running our decals on the car, so that was the arrangement. Every year, his Christmas card to the shop would have a note inside, requesting a dozen contingency decals be mailed to the shop.In ongoing oil analysis testing, we consistently saw high silicate content in the engine oil, when using the K&N elements. And we also saw snotty-running street cars, where K&N filter oil had been drawn into down stream air sensors and has fouled them. Just how much oil does a K&N air filter require? Too little and the filter becomes as useful as udders on a bowling ball. Too much oil and your street driver is suddenly running like trash.
For the cost of a paper element you can simply drop in and forget for a few thousand miles, the cotton-gauze filters are a wonderful and delightful waste of money. That are introducing unnecessary contaminants into your engine.
