In my previous post, I mentioned the approach on air intake modifications and how I feel that the standard stock air box is best in terms of temperature shielding. Moving forward, it was time to improve the airflow with a more flow superior element.
There are many aftermarket filters available and if you surf the web, you will notice that everyone expresses different opinions on what's best and what's bad. Of course, I have also been cautioned by some other car enthusiast that an oiled cotton filter like K&N is not good for the Mass Air Flow (MAF) sensor as there is a belief that the oil molecules would coat the wire of the MAF sensor. K&N claims that there is no issue so I decided that I should give it a go since this was marketed as "The world's best air filter."After all, as in all engineering applications, it is always great to experiment since the risk isn't of any massive magnitude.
I purchased the K&N on the 19th September and I have been using it for just over a month now. In the perspective of performance, there wasn't much noticeable improvement so do not expect a sudden surge in acceleration like what some others claim online when upgrading air filters. I suppose much that is being said online is an exaggeration as this is no turbo upgrade. I did 'feel' that the high end pull is slightly better but then again, this could be psychological as my V6 is already full of torque to begin with. But I can assure you that there was no power loss throughout the rev range.
What really surprised me was the better mileage. If you look at my chart from my Gas Cubby iPhone app, you will see that after the K&N was installed, I achieved 9.4 - 9.7 km/L on a tank of 95 octane fuel. My driving habits and routes were more or less similar and the improved mileage is credible. I'm now running on my 4th tank of fuel after the filter replacement and I am expecting an approximate 9.7 km/L once again. A noticeable gain of about 1km/L is really pretty impressive, especially if you consider the prices of fuel these days.
To conclude, the high flow K&N filter does promote mileage gains and some fuel savings to begin with. The S$118 K&N is quite worth the investment as it is washable and reusable with a claimed million mile warranty. Personally, I do not think anything will really last a million miles so changing it out once in a year or two wouldn't be such a bad idea anyway.