K&N Engine Air Filter: Increase Power & Acceleration, Washable, Premium, Replacement Car Air Filter: Compatible with 2010-2015 BMW L6 (X1, 135i, 335i Coupe), 33-2458

Gained a little go but fuel economy saw about an 8% increase

What can I say, this is my third K&N air filter, this one was installed in my 2011 BMW 335xi. The difference in performance is immediate and somewhat startling. I have no idea how much additional power is being generated, but it's fantastic overall. Low end torque is immediately improved an noticible, no increase in noise or other changes. For those that know BMW's, the 2010 335xi used the N54 twin turbo engine. I owned this vehicle and used KN air filters, it was quite a car. Then I traded it for a 2011 335xi, which uses the N55 "twin power" turbo - note the difference, this engine has only one turbo whereas the N54 has two turbos. There is a definite decrease in torque with the N55, and I was unhappy to say the least. My 2011 BMW had the sport package and nav, though, which is why I upgraded - the seats alone are worth the upgrade. Anyway, after installing this new KN air filter, my 2011 335xi runs with what appears to be at least the same, if not more, power than my former twin-turbo BMW. BMW should include these as standard equipment, for the price, it's a no brainer. Just buy it.

I've always throw in a K&N whenever I get a new (or used) car. Finally spent the money on one for our 2011 335i. Usually I feel little when it comes to performance with the K&N installed. Not so with the 335!! My guess is the turbo loves that extra air. Defiantly feel a kick! Throttle response improved, lower end torque feels stronger. When the car shifts up to 2nd is when I really feel a stronger pull. Highway driving and passing all benefitted. Strongly recommend for 335 owners. Note: Your mileage will suffer for a while you get the "spirited driving urges" out of your system, fun fun fun! As for any concerned with regards to the K&N oil soiling your MAF sensor, buy a can of MAF cleaner after a few weeks of running the filter. Heck, it probably needs a good spray down with cleaner anyway.

I didn't buy this for any power gains, it's definitely way less restrictive than the paper filters so that's gotta be good, besides, you can clean and reuse so what's not to like. I can't really say I felt any improvement, like I said I didn't buy it for that reason, but a less restrictive air filter technically means more air going into the engine, in our case (turbocharged engines) also means faster spool.This is just a good air filter you don't have to toss in the trash and it's a lot less restrictive than the paper media counterpart. And it's cheap.

Fit perfectly in a 2012 135i and so far is meeting all expectations for a replacement filter. I've always been happy with K&N drop in replacements in my motorcycles and cars.

Noticed absolutely no power difference which is okay, but you can definitely hear more engine bay noise which is a good thing. Reusable and long lasting? im glad i switched from the typical paper one time filter.

I installed this on my 2012 BMW 335i xDrive Coupe. It is super easy to install.. Just pop up your hood and all you gotta do is unclip 4 corners and lift up the cover take out old filter put the K&N filter in. The whole process takes less than 5 mins. I love the fact that it's washable/reusable... Environment friendly (somewhat oxymoron driving a 335 lol).I think I could hear the difference in sound (very minute but certainly now a worse sound). MPG and performance will have to wait and see.. But I didn't have any problem yet so I'm guessing it can't be bad.

For its cost, this air filter is quite phenomenal. I drive a 2011 BMW 335i Xdrive, and the change for me was noticeable instantly. After 1 year, there's only 8000km on the car and so the original filter was still quite new. I think that this filter has made my car sound different (certainly an audible difference by before-and-after video recording in my garage) and also feel more responsive. We'll see if it changes the fuel economy.I'd recommend it 100%.