K&N High-Flow Original Lifetime Engine Air Filter: Increase Power: Premium, Washable: Compatible with 1981-2021 Faw/Ford/Infiniti/Nissan: (See product Description for Select Models) 33-2031-2

A perfect drop-in fit for my 2013 Nissan Altima 3.5S with factory air box and intake. Throttle response was noticeably improved over clean/new factory paper filter, ESPECIALLY at lower RPM (which this engine w/ the CVT tends to prefer). You'll notice throttle response increase much more than an overall power increase. MPG climbed right around 1 full mile per gallon (hovering between .9 and 1.1 additional from my calculations at the gas pump and the in-dash display). Intake growl increased a little when really getting into the throttle, but is same as stock when you're not driving aggressively. If you have a CVT (Altima, Maxima, Murano, Pathfinder, etc.), then this seems to make sense due to the improvement in throttle response (how power applied to the wheels tracks with pedal movement). If you're in a truck with the std 6-speed auto, then it may not make much of a difference other than tripling your filter change interval. Going from 27mpg to 28 mpg will pay for the filter alone (I already have a recharge kit from K&N, also found here on Amazon).Don't expect miracles, but it's a quality product that delivers reasonable return on investment. If you drive like a fool, don't expect your MPG to go up. But you will enjoy the slight noise improvement and the throttle response.

Perfect fit!

My '01 Frontier is now a high performance machine! Ok, not really. There is definitely a noticeable difference since I installed this filter though. My gas mileage and power have improved.

I had read the rave reviews for these air filters and wondered about them. I also noticed that at a very popular auto parts store one of these was going for around $50 plus tax here - that's quite a bit of money for an air filter. But I found the same filter on AMAZON for about a third less with free shipping - so, I decided to buy this air filter from AMAZON. Well, the results were just spectacular: I went from getting 27 mpg to 31 mpg in my 2002 Nissan Altima - and this filter was the only thing I changed. Buy this filter - it really works! The racing guys know what they are doing. Just think - in less than 4 tanks full, this air filter pays for itself in gas savings - and from there you are saving real money. Before I had never thought of an air filter as being an investment - but this one is. Plus, it's a lifetime filter - just clean it and re-install it in your auto and go. Wow!

Our dealership wanted to charge us $150 to change our engine air filter. This has to be one of the easiest maintenance items a car owner can do. I decided on the K&N because I like the idea of a washable / reusable filter. Easy to install, easy to clean. Overall a great product.

This product is very good, not great, but good. I say very good because it sounds amazing & defiantly improved the horsepower immediately. But on the flip side I have noticed my gas mileage has gone down a little. The only other issue is it didn't fit perfectly. Actually I had to shove it in and broke a sweat putting it in. But it does fit, increases horsepower, but does not improve gas mileage like stating.

You get what you pay for with K&N products. Have purchased several K&N air filters before and keep coming back to them. Quality and long lasting.

Perfect fit for our Murano. Nissan dealer wanted $43 for one that had to be replaced every year.