Guys I have about 6k on my 09 4-teen and I am going to change the filter, because the guy at the shop says that with my full hindle exhuast my bike is not breathing and that I'm killing my engine with the stock filter, and that I should change to K&N filter for better performance... If this is true, should I go with the K&N or another brand? Thanks in advance for your help

That's bullshit if you ask me! Brock's CT makes the most powerful exhaust and says it is better to stick with the OEM filter. I heard K&N were great though and you save money in the long run but I rather use the OEM and change it every 2 oil change (6000-6500 miles).

Consensus was BMC Race filter #1 when I did my homework several years back.

I got one. Never installed it. GUess I shopuld try it some day, hey?

BMC is something like 1-2 oz heavier than a K&N. The BMC is very hard plastic frame w a VERY fine mesh on it. The K&N is made of plastic (looks softer and flexible but must admit never saw one in life) and foam rubber. To me the K&N looks like it would filter better if you ask me. The BMC might flow just a hair better??

In any case, yo will only get .5-2 hp increase so stick to OEM. That's what I do. Prolly throw the race filter in to do my hardest riding just so I can say I used it ....doubt it will make a dif for my level of skill. I have heard that the mapping for a race filter compared to OEM is pretty much indistinguishable....just doesn't make a big enough dif. I ran a BMC race filter map with OEM and it was just fine.

The aftermarket street fiters get close to the same performance as the race filters. I still feel safest using OEM. Pull the steel screen off of that if you want.

When I first looked at my stock filter at about 3000 miles,it was so filthy in the middle.I have a K&N now.I had a Pipercross race but it wasn't dirty at all.That kinda scared me cause I don't think it was catching any dirt.So I put about 2000 miles on her this year;Will clean it this year when I change the oil in the spring.
Craig

I think the disconnect is with the year of bike being referred to.

Not sure about a 2008, but I do know that for the 2012, it seems those in the know say that the aftermarket's are a complete waste of money, given how increased the flow is on the improved 2012 airbox and filter.

Not sure about a 2008, but I do know that for the 2012, it seems those in the know say that the aftermarket's are a complete waste of money, given how increased the flow is on the improved 2012 airbox and filter.

Interesting-- and I always heard that even on the gen 1, the flow of the OEM is not all that much better than an aftermarket filter either.

Perhaps it is that ther really is NOT nearly as much pressure in that airbox as many of us would think.

Hub hooked up a gauge one time to measure the ram air effect and the air pressure was not a whole heck of a lot even at speed. I bet the engine drawing air creates a lot more flow than the ram air pressure. ....or at least the draw offsets the pressure which would explain the low pressure in the airbox.

In any case, if the airbox pressure is low with an OEM filter, how much will greater flow really help? Perhaps some if you have a high flow exhaust as well.

Generally speaking, it is $100/hp that you can expect to pay when buying mods. For this reason, I have always said that if the claims of 1-2 hp increase are genuine, then a high flow filter is a bargain mod. I still do not know if it is worth the risk of causing premature ware on the engine for street riding. Keep your race filter and throw it in when you are at the track. It'll keep the larger chunks of debris from going in the motor which is better than no filter at all.

* Last updated by: Rook on 9/26/2012 @ 3:45 PM *

Find a new mechanic and find a new shop. Stick with stock OEM.

Not sure what the stock filter looks like because my bike came with a BMC. I know on my ZZR 1200, the K&N I put in was a much more durable unit than the stock foam filter, which tends to shrink and harden from heat over time. The K&N had a Lifetime Guarantee. BMC looks to be of similar quality. Don't really care about the increased power claims.