I have a '06 S40 fixing to change the Air Filter to a KnN. A good deal for 40 bucks from a Suzuki dealership ( negotiating skills are getting better! ) but just wondering will there be a noticeable difference in power with this change alone? Seems I've read in some other topic where there could be such a difference where a carb jet change may even be required, I definitely hope not! Any comments would be appreciated!

                                                 Thanks
                                                  Ken

 Ok, maybe I should have mentioned my'06 is strictly stock before this KnN filter change in 1 more week. Forgot, I did take the Brass Plug out of the "Idler Jet"? to adjust it to 1 and a half turn out.

There have been lab tests on K&N filters and the results were that although they let in more air, they also let in more dirt than a factory filter. The articles say that vehicle manufacturers would have used a performance inhancing design like the K&N and its numerous clones in order to achieve better mileage and performance, but they don't because these designs necessarily allow more particulate matter to pass through into the engine.

An interesting side note was the reason given for oiling these type of filters.  The type of filter oil needed must be able to be completely dissolved with soap and water.  The oil is needed to stop road oils and contaminants from adhering to the filter element.  Instead, they accumulate on the oil surface and are washed away when the filter is cleaned.  Without the oil, contaminants such as petroleum contaminated exhaust smoke and chemical or oil comtaminated air pollution will be absorbed into the element and require solvents to remove, which will then damage the element.

northshore_paul wrote on 07/09/08 at 19:48:47:




This is an old story....a vehicle manufacturer spends millions of dollars and employs graduate engineers to develop a vehicle which is the best compromise possible for public acceptance.  Then along comes an assortment of small businesses that offer "improvements" which the original manufacturer decided not to incorporate in his design for very good reasons.  An air filter has to filter the air at a level deemed acceptable for engine long life.  This filter is a compromise.  Then along comes K&N and its clones who promise improvement in performance and lie about their filters removing more contaminants than the factory unit.  Then comes independent tests which visually show the dirt that K&N lets through, as compared to the factory filter.  Look at all the oil additives, like Slick 50, and so on.  Lycoming Aircraft Corp. tested all of them, and said that at best, the only thing some of them will do is not damage your engine, and at worst, they will damage your engine.  Look at the false claims Splitfire spark plugs made for its sparkplugs.  The Federal Government prosecuted them for false advertising.

Seems like the safest thing is to trust the vehicle's manufacturer.

   I would think if your warm up time is less your not getting as much air and running richer.

  Its hard to tell by one test ride.

  Do you and your dad weight the same,running the same jets,and same muffler.the same gas mileage.

It wouldn't matter if I rode his bike and he rode mine it would still be faster. And at the time yes they both had the same exhaust, jets, air filter and dino oil. Things are a lot different now and the results are still the same. I don't know if mine was broke in different or what.