TWMX All Access: K&N Engineering

If you’re familiar with K&N Filters, it may be from their involvement with things as diverse as drag racing, off-road trucks and buggies, the IRL, or even the street automotive aftermarket, but it wasn’t always like that—their roots run deep in the motorcycle industry. Chris Bennett, K&N’s Powersports Merchandising Manager, explains, “Ken Johnson and Norm McDonald were two desert racers who were trying to get more horsepower. They kind of fell upon this technology while dinking around in their shop in the late 60s.”

After one look, K&N’s filters are obviously different from the normal oiled foam setup that is standard-issue for the motorcycle industry. “Our filters are comprised of four layers of gauze sandwiched between two layers of wire mesh. The main difference between K&N and foam filters is that with our pleating, we’re able to offer more surface area, so we can go twice as long as a foam filter, which would be at its max as far as dirt impaction. The pleating also gives the filter rigidity, and the wire mesh helps straighten out airflow and catch big particles. We’re the second largest consumer of surgical cotton gauze in the United States, second only to Johnson & Johnson. With a smile Chris added, “Of course you’d expect them to be number one.”

Filter Construction

Nearly all the machinery at K&N is proprietary and constructed in K&N’s machine shop, including the pleating machines that give the screen/gauze laminate its unique look. Chris explains, “Depending on the application, the depth of the pleats and their spacing will differ. Everything is tested to achieve optimal airflow, and determine how the airflow is affected by pleat pattern. We’re really proud of those machines. We still have the original machine from back in the day, which is called Plinky. I don’t think it’s in operation any more, but we’re keeping it around as a museum piece.”

“In the old days, they tried cutting the pleats on a bandsaw, but couldn’t get the cuts nice and smooth like they needed, so they used to freeze the material in ice, and cut the blocks of ice. Then they’d let it thaw out and make their filters. By today’s standards, it was a tedious process.”

Fortunately, as they’ve modernized, things have gotten a lot more efficient. Watching production of filters is interesting, and Chris was happy to run through the process. “As the finished pleated material comes out of the pleating machines, it’s cut into the correct widths for various applications. Usually the rolls are 20 inches wide, so they can be cut into three or four different widths for various filters, and all of those are done in one shot. Then they come to a pleating station, where they get made into specific part numbers. They’ll hand-count each pleat, depending on the part number, cut them to length, and join the ends of the pleats with an aluminum binder clip.”

“After everything’s done with the pleating process, they go into bins with a specific mold for each filter. Depending on how popular the part number is, it determines how many of the molds we make. On some of the one-offs there might only be one or two molds, while on more popular filters, there will be a lot more.”

“They pour the urethane or Plastisol into the bottom of the mold, then set the pleated material into it. Each mold has built-in supports to hold it all together. Then they run it through the oven to cure it.”

“Halfway through, there’s another station where they flip the filter, do the bottom side, and send it through a second oven. After it comes out on the other end each filter is hand-trimmed to remove any flash or bleed-over and goes through final inspection.”

“After that, they go to an oiling station with an automated sprayer. They operator plugs in the part number of the filter, and the computer knows how much oil needs to be applied, and it spins on the turntable until it’s finished. It may look unfinished after it’s been sprayed, but the oiwicks out to cover the gauze. All K&N filters come pre-oiled, so the consumer doesn’t have to deal with it.”

“It’s a hands-on-intensive product. Granted, the technology and automation is good, but we still employ a lot of folks here who do a great job in building a quality product.”

“We sell to the large distributors, Parts Unlimited, Tucker Rocky, White Brothers and similar, but we also sell to consumers at a price that doesn’t undercut our dealers.”

After commenting on the small quantities of various filters coming through production, Chris noted, “We definitely want to keep a certain level of popular inventory items, like the top 100 part numbers. But for the most part, it’s a build-to-demand type of a deal. It’s all integrated into our Business Management System that tells the folks in manufacturing what needs to be built, and how many. We have three shifts that run around the clock. One side of manufacturing is dedicated to round filters, while the other side is devoted to flat panel filters, which are mostly used in automotive applications, though you’ll also find some street bikes and ATVs that use that style of filter. The flat panel manufacturing is less hands-on than the round filters, taking advantage of more automation.”

“We’re in the process of fully automating this warehouse. Soon it’ll be one of those deals where you plug in a part number, and it’ll go out and collect everything, then dump it off.”

Inside R&D

After running through production, we made the hike to K&N’s R&D facility, which is among the original group of buildings that comprised K&N’s original headquarters before they built their current facility, which measures at just under 300,000 square feet. K&N also has a similar-sized building in a separate location that they use as their distribution center.

While making our way to R&D, Chris commented, “People think, ‘Ah, it’s an air filter. There can’t be that much technology in it.’ Nothing could be further from the truth. Obviously for a motor to breathe well it needs a good filter, but it also has to stop dirt. We do a lot of research and development for that exact purpose. We want to flow as much air as we can, but still protect the motor.” R&D houses a large room for permeability tests, and an engine dyno, as well as their race support and race shops, as well as a room with a microscope that they use to check for warranty issues, and that’s where we met with Rich Dwyer, K&N’s R&D Manager.

Pulling a view of the gauze material used in a K&N filter up on a monitor, Rich said, “This actually is a pretty good picture of what the dirt sees as it comes into the filter. Some people will hold a filter up to the light and say, ‘See all the little holes in it? How well is that going to filter?’ But each one of these fibers are in the airstream and they kind of sweep the air. As the air goes through it, it has to take this convoluted pathway, and dirt gets out of synch with the airflow, and they get snared in the tacking agent.”

“When a dirt particle hits it and gets trapped in the tacking agent, the tacking agent wicks onto the dirt particle, and then the dirt particle will also snare more dirt, and it becomes part of the process. That’s why our filters truly do get more efficient as they get dirtier…to a point.”

Rich then showed us the area where they do permeability tests. The room is set up to be climate controlled 24/7, and is set at standard levels used for testing of 70 degrees, and 50% humidity—both of which were much lower than conditions found outside the building. Why such close tolerances? The testing is all based around the amount of dust that gets through the filter and makes it to an “absolute” filter, and it’s all based on the pre- and post-test weight of that filter.

Rich explained, “It’s a simple concept, but very complicated procedure. Basically you put either fine or coarse dust in the hopper, you have a pre-determined airflow depending on which vehicle it’s going to go on, and what size motor. You start it up and it pulls air through. You feed dirt into it, and weight the absolute before and after. You know how much dirt was fed into it, you know how much was caught, you find out how much is in the absolute. Do a little simple math, and you know how efficient your filter is.

“To do one test on here takes just about a day. Before you weigh the absolute, you have to put it in the oven and bake the moisture out of it. You have to do the same afterward, because as soon as you remove the absolute filter from the system, it starts absorbing moisture, and the weight immediately goes up.”

Rich also showed off a tray of foam filters that they’d tested. “What we found with the foam filters is that they’re very efficient initially, but as they get dirty, they stay pretty dry and become less efficient as they go through their lifespan. As a dirt particle hits the foam, it occupies that space and the tacking agent that they use on the foam filters is so thick that it doesn’t wick onto that piece of dirt that it captures. What you wind up with in effect, is like gopher holes through it. To where a dirt particle enters into that passageway skips over the dirt until it enters the motor.

On a foam filter the key to it is understanding that as soon as you clean it and oil it, it’s as good as it’s going to be. As soon as it gets a little dirty, you need to change it. You’re going to service a foam filter a lot more often than you are a K&N Filter because the K&N Filter filters well in the beginning, but as it gets dirty…to a point…it gets more and more efficient as it goes along.”

The Future

Leaving R&D and headed back to the corporate headquarters, Chris commented, “Powersports are currently only a small percentage of K&N’s annual sales, though they’re working on changing that. A lot of people tend to shy away from our stuff because it’s not what they’re used to.  Obviously it’s where our company was founded on. We kind of let it get away from us, while growing other areas of the business. But we’ve got a renewed sense of focus, pumping in research dollars, and investing in this product line. We wouldn’t do that if we didn’t believe it was a benefit to the folks who use it.

These filters, when we’re talking about motocross applications, are real easy to install and maintain, compared to a foam filter. Anyone who’s serviced a foam filter knows that you get sticky, gooey hands. Ours are really clean and simple, Like the CRF450s, I understand are a pretty difficult filter to change. Our filter for that application is a two-piece deal, with a lid. Once you remove the lid, the filter is pliable, and you can squeeze it between the frame rails, put the lid on, and you’re done. Our filters are designed to get about 25 cleanings out of them, which I’d say is substantially longer than what you’d expect from a foam filter.”

“A lot of people are familiar with K&N, but they’re like, ‘Oh, that’s for my car.’ A lot of them don’t know the history of the company. It’s like, ‘No, we were here first.’ But we are getting a lot more play now, especially with the mini craze. A lot of the people are running our clamp-on filters there. We like that, but we’d rather be known as the big bike guys, too.”

Contact

K&N Engineering, Inc.
1455 Citrus St.
Riverside, CA  92507
(800) 858-3333
www.knfilters.com

ed airflow depending on which vehicle it’s going to go on, and what size motor. You start it up and it pulls air through. You feed dirt into it, and weight the absolute before and after. You know how much dirt was fed into it, you know how much was caught, you find out how much is in the absolute. Do a little simple math, and you know how efficient your filter is.

“To do one test on here takes just about a day. Before you weigh the absolute, you have to put it in the oven and bake the moisture out of it. You have to do the same afterward, because as soon as you remove the absolute filter from the system, it starts absorbing moisture, and the weight immediately goes up.”

Rich also showed off a tray of foam filters that they’d tested. “What we found with the foam filters is that they’re very efficient initially, but as they get dirty, they stay pretty dry and become less efficient as they go through their lifespan. As a dirt particle hits the foam, it occupies that space and the tacking agent that they use on the foam filters is so thick that it doesn’t wick onto that piece of dirt that it captures. What you wind up with in effect, is like gopher holes through it. To where a dirt particle enters into that passageway skips over the dirt until it enters the motor.

On a foam filter the key to it is understanding that as soon as you clean it and oil it, it’s as good as it’s going to be. As soon as it gets a little dirty, you need to change it. You’re going to service a foam filter a lot more often than you are a K&N Filter because the K&N Filter filters well in the beginning, but as it gets dirty…to a point…it gets more and more efficient as it goes along.”

The Future

Leaving R&D and headed back to the corporate headquarters, Chris commented, “Powersports are currently only a small percentage of K&N’s annual sales, though they’re working on changing that. A lot of people tend to shy away from our stuff because it’s not what they’re used to.  Obviously it’s where our company was founded on. We kind of let it get away from us, while growing other areas of the business. But we’ve got a renewed sense of focus, pumping in research dollars, and investing in this product line. We wouldn’t do that if we didn’t believe it was a benefit to the folks who use it.

These filters, when we’re talking about motocross applications, are real easy to install and maintain, compared to a foam filter. Anyone who’s serviced a foam filter knows that you get sticky, gooey hands. Ours are really clean and simple, Like the CRF450s, I understand are a pretty difficult filter to change. Our filter for that application is a two-piece deal, with a lid. Once you remove the lid, the filter is pliable, and you can squeeze it between the frame rails, put the lid on, and you’re done. Our filters are designed to get about 25 cleanings out of them, which I’d say is substantially longer than what you’d expect from a foam filter.”

“A lot of people are familiar with K&N, but they’re like, ‘Oh, that’s for my car.’ A lot of them don’t know the history of the company. It’s like, ‘No, we were here first.’ But we are getting a lot more play now, especially with the mini craze. A lot of the people are running our clamp-on filters there. We like that, but we’d rather be known as the big bike guys, too.”

Contact

K&N Engineering, Inc.
1455 Citrus St.
Riverside, CA  92507
(800) 858-3333
www.knfilters.com