K&N Air filter swap!

[E Zurcher]

I would love to run the stock filter but the price is ridiculous for a throw away filter. I'd rather spend the money an a washable and clean it every year for a couple of bucks.

 

[icemansid]

Was your air box modded or stock?

 

[JPunisher]

I've had K&N and BMC, and in a few bikes.
Compare them side by side and the only difference you can see is the color.
Compare the race filter to the standard, and the race version is about 2/3 the thickness.

Many times the comment comes up as to how hp is lost with a K&N...yet the evidence never surfaces.
Don't belive everything you hear.

This is the closest I have seen to evidence. This is from Brocks Performance FAQ page:

Q: Does Brock's recommend the use of K&N or BMC aftermarket street or race air filters?

A: Brock’s Performance does not currently recommend or endorse the use of ANY BRAND aftermarket “streetâ€￾ filters. It has been our experience that they do not perform as well as stock and can actually work much worse. The reduced air flow compared to stock; disrupts our known good mapping, decreases fuel mileage, hampers driveability, significantly reduces power levels, fouls plugs, creates excessive soot at the exhaust tip, generates excessive carbon deposits in the intake track etc. When over-oiled we have seen these problems increase dramatically with registered horsepower losses in the vicinity of 10-15+ with greatly increased fuel consumption. You can't go wrong with today’s modern OEM air filters, in regard to engine life and consistent performance.

We have noticed measurable performance gains when using both K&N and BMC aftermarket “raceâ€￾ filters compared to stock, but these filters are for racetrack or low mileage use only since they basically filter out bugs and birds!

Registered Brocks Performance exhaust system owners can read additional test details in our private owner section linked below (see note 18):

Here is the reference: Brock's Performance FAQ

JPunisher

 

[sixpack577]

This is the closest I have seen to evidence. This is from Brocks Performance FAQ page:



Here is the reference: Brock's Performance FAQ

JPunisher

Finally some good info, Brocks definitely know their stuff.
I would agree that the thin race filters would have to perform better than stock when properly tuned.
As an engine is just an air pump; more air in, more air out, and tuned correctly=more hp/tq.