Is the K&N air filter worth the money??

[rboe]

I bought one for my KX550 years ago and it improved the mileage. For the CB, since it has EFI and other fun computer stuff I'm sticking with factory filter. Besides; all the dirt bikes really frown upon the K&N for dirt bikes because of their poor dust filtering and Phoenix is very very dusty; it's a damn dirty state. YMMV.

[DAC]

Maybe this is too simple a solution, but I'd like to see somebody just bench flow the thing and see what it does. So, if the CB needs XXX cubic feet per minute in a state of high tune (new pipe, PCV), then what is the air flow requirement? Does the stock set up give enough flow?

I've see on some threads on oil (yes, I've read some of the dreaded oil threads) where people back up their oil preferences with actual used oil analysis. Back when I was a kid, I remember reading in magazines that the racer types would do a lot of flow analysis on cylinder heads and manifolds. So, I imagine someone has done this on K&N filters.

I do remember seeing one comment from calsci (again, from an oil analysis thread) where the guy said that your wasting your money on air filters. Most all of them, supposedly, flow way more air than you will need.

[GUNFTR_imp]

I've had a K&N or an Airaid in every car or truck I've owned since 2000 as well as every street bike. Never had a single problem, and enjoyed the increased sound from the intake on every vehicle. They last virtually forever if you clean them correctly. My 1988 4Runner notched 238,000 miles on the odometer before I sold it using a K&N. They do, in fact, breathe better because if you've got a bike with a carb instead of fuel injection, you need to rejet much richer when you make the switch, especially if coupled with a non-restrictive exhaust. For me, they are totally worth the $$.

Places that change the oil for your cars don't like them cause they can't play the "you need a new air filter" trick every other oil change.

[Dakota_imp]

Unless you have characterized the stock air filter with a manometer, you really can't do more than speculate as to the restriction. This doesn't require costly equipment.

FWIW, Cummins once had a note on their European web page indicating NOT to use KnN filters due to poor filtering performance. While they are not EXACTLY the same, OEMs used to use oil wetted metal gauze for their air filters. A GM powertrain engineer told me that poor air filtering was one of the main reasons why 1950s engines had such short engine life. Caveat emptor.

[lackskill_imp]

Unless you have characterized the stock air filter with a manometer, you really can't do more than speculate as to the restriction. This doesn't require costly equipment.

FWIW, Cummins once had a note on their European web page indicating NOT to use KnN filters due to poor filtering performance. While they are not EXACTLY the same, OEMs used to use oil wetted metal gauze for their air filters. A GM powertrain engineer told me that poor air filtering was one of the main reasons why 1950s engines had such short engine life. Caveat emptor.

while I agree that you can't do any kind of quantitative analysis without the proper equipment, it is pretty easy to draw a conclusion. For the most part, filtration efficiency and flow rates have an inversely proportional relationship. I'd argue that K&N filters probably flow higher rates that just about any other filter on the market. While on a well worn relatively loose tolerance high mileage car/truck motor, the extra filtration may not be necessary, but I'm guessing (literally, I don't have any tolerance specs at hand) that the clearances on most motorcycle motors is much tighter. But at the same time, if it's a well worn loose tolerance street motor, why do you need incrementally more airflow? More air in means that you need more fuel in as well. Unfortunately, that doesn't always translate to more power.

I'd also wager that if you took multiple identical motors, half with oiled filter media and the other half with paper filter media, and ran them side by side over the life expectancy of the motor that the UOAs would bear much higher wear metal concentrations in the oiled filter media motors. My gut tells me that on motors with lower wear tolerance, that the difference in lifespan would be significant. On motors with higher wear tolerances (such as the aforementioned 4-runner) that this difference would probably never come to light.

Although the application doesn't come close to applying here, this is a pretty good quantitative analysis of several different filters:

http://www.nicoclub.com/archives/kn-vs-oem-filter.html

[Red Mist_imp]

I've used K&N filters in several different vehicles, from a Ford V10 RV chassis to a Toyota Yaris. With the Ford, I noticed an immediate performance and gas mileage improvement, around 10 percent. Not so much with the Yaris, but with the large-displacement engine one would expect a more noticeable increase.

I just did an ECU reflash on another bike I have, along with a K&N filter, and the difference was astonishing. Fuel mileage is about the same but far more power everywhere. Most of that is due to the reflash which changes ignition timing as well as the fuel mapping but some is due to the increased airflow. The K&N was factored into the reflash.

K&N is pretty militant and aggressive about asserting that its products meet or exceed all OEM specifications and they have decades of research and data to prove it. I have confidence in their products and have good results with the performance enhancements, as well.

I am not much for loud pipes any more; with an ECU reflash and high-flow air filter such as the K&N, retaining the stock exhaust, BIG power and driveability gains are really just a few computer clicks away for many vehicles, cars and bikes alike. I have had so many loud noisy bikes I can't recall them all; I'm lucky I never got a citation, especially for my ear-splitting Harley.

Why not use the ECU as the way to get big power and driveability gains, keep the bike quiet and civil, and have a nice clean exhaust emissions into the bargain? Makes sense to me.

[lackskill_imp]

One of the critical seat of the pants mistakes that people always make is comparing performance and mileage on a brand new filter vs a dirty old filter. The subsequent improvements are often byproducts of an engine running more efficiently because of a fresh filter, which leads to needing to use less throttle, and that turns into MPG improvements.

[Deanohh_imp]

I've used K&N filters in several different vehicles, from a Ford V10 RV chassis to a Toyota Yaris. With the Ford, I noticed an immediate performance and gas mileage improvement, around 10 percent. Not so much with the Yaris, but with the large-displacement engine one would expect a more noticeable increase.

I just did an ECU reflash on another bike I have, along with a K&N filter, and the difference was astonishing. Fuel mileage is about the same but far more power everywhere. Most of that is due to the reflash which changes ignition timing as well as the fuel mapping but some is due to the increased airflow. The K&N was factored into the reflash.

K&N is pretty militant and aggressive about asserting that its products meet or exceed all OEM specifications and they have decades of research and data to prove it. I have confidence in their products and have good results with the performance enhancements, as well.

I am not much for loud pipes any more; with an ECU reflash and high-flow air filter such as the K&N, retaining the stock exhaust, BIG power and driveability gains are really just a few computer clicks away for many vehicles, cars and bikes alike. I have had so many loud noisy bikes I can't recall them all; I'm lucky I never got a citation, especially for my ear-splitting Harley.

Why not use the ECU as the way to get big power and driveability gains, keep the bike quiet and civil, and have a nice clean exhaust emissions into the bargain? Makes sense to me.

Sounds great. Please report on how flashing the cb1100 ecu works for you.

[Red Mist_imp]

I've used K&N filters in several different vehicles, from a Ford V10 RV chassis to a Toyota Yaris. With the Ford, I noticed an immediate performance and gas mileage improvement, around 10 percent. Not so much with the Yaris, but with the large-displacement engine one would expect a more noticeable increase.

I just did an ECU reflash on another bike I have, along with a K&N filter, and the difference was astonishing. Fuel mileage is about the same but far more power everywhere. Most of that is due to the reflash which changes ignition timing as well as the fuel mapping but some is due to the increased airflow. The K&N was factored into the reflash.

K&N is pretty militant and aggressive about asserting that its products meet or exceed all OEM specifications and they have decades of research and data to prove it. I have confidence in their products and have good results with the performance enhancements, as well.

I am not much for loud pipes any more; with an ECU reflash and high-flow air filter such as the K&N, retaining the stock exhaust, BIG power and driveability gains are really just a few computer clicks away for many vehicles, cars and bikes alike. I have had so many loud noisy bikes I can't recall them all; I'm lucky I never got a citation, especially for my ear-splitting Harley.

Why not use the ECU as the way to get big power and driveability gains, keep the bike quiet and civil, and have a nice clean exhaust emissions into the bargain? Makes sense to me.

Sounds great. Please report on how flashing the cb1100 ecu works for you.

Sounds great. Please report on how flashing the cb1100 ecu works for you. Like to do that, unfortunately I don't think anyone's got one worked up yet. Somebody has to be the "lab rat" and provide a bike for a few days. I used Guhl Motors for my Yamaha, they have a great reputation, but their bike ECU reflashes are limited to a few models.

I would have to know what changes to expect; frankly I'm very happy with the way my CB1100 runs now so I doubt I'd do anything to it.

Someone will get around to it eventually, though.

BTW that Street Triple R is a great bike, they did it right.

[banjobart_imp]

I use K&N air and oil filters on everything. I like the idea of the K&N air filter over paper or foam, seems to be a better filtration medium to me.

I stock up when an Ebay seller has a sale.