K&N Cold Air Intake Kit: Increase Acceleration & Towing Power, Guaranteed to Increase Horsepower up to 14HP: Compatible with 4.0L, V6, 2008-2019 Nissan (Frontier, Xterra, Pathfinder), 63-6014

Installation took about 45minutes. Box contained everything it needed and the filter works great. I can already feel an increase in power in the lower end and the engine sounds great when you put the pedal down! K&N has always been my go to for CAIs and filters and I don't see that changing anytime soon.

This is a well-engineered bit of kit, I especially like the design of the heat shield with its cushioned seal. I was a bit concerned after seeing another review claiming rattles given that non-OEM can propagate poor results. I was also concerned about fitment as the Amazon Garage claimed it wouldn't work on my 2009 CrewCab , short bed, 4x4, 4.0L Frontier. Took a chance as the 4.0 Xterra/Frontiers are nearly identical mechanically over their respective model years. I took my time installing, utilized all the sealing material, trimmed to fit perfectly and double checked my work...net result, zero rattles, perfect fit (almost, see below), and per my butt dyno, the claimed power gain is at least close which is unusual for a CAI, usually the cool sticker is about as effective. It seems some real thought and engineering went into this, it also tells me the stock setup was fairly restrictive. As another reviewer pointed out, the plastic tube reduces the chance for heat soak, and the heat shield is effective. I hemmed and hawed at dropping the $$'s on a CAI, but it turns out you get what you pay for, this time in a good way. As for sound, it's stock quiet at idle, a little louder (in a good way) in normal driving conditions, and obnoxious at WOT. At WOT I like it, my GF hates it, 'nuff said. The fitment caveat, kit comes with a replacement crankcase ventilation hose to replace the stock piece, it is about 6" too short, and half the diameter so you will be buying that elsewhere. Maybe why Amazon claims the kit doesn't work?? Otherwise, it's a perfect fit, but you'll need the 5/8's hose. Overall, very happy

The product box arrived in pretty rough shape, however the contents appeared to be okay. However there is one issue, the sealed parts bag that was provided appears to have supplied the wrong hardware type, included should've been 6 M6 sized bolts that correspond with the provided nylon lock nuts. The bolts provided are definitely too small. Email sent to KN customer support.

K&N does a super job of making its intake system fit perfectly and with minimal installation time. It is relatively quiet and looks great also. The truck breathes easier and power or fuel savings are more subjective than measurable.

Purchased 7 months ago. Relatively simple install. Upon starting I could immediately tell it was pulling air through the crack by your hood, where it was not before. Can for sure feel the power. Noticed I got up to speed a little quicker and acceleration felt SMOOTHER. Remember it is just 15 HP so it is not a huge improvement. The sound is honestly the best part. If my window is down I can hear it pulling air through the hood when accelerating. When you romp on it, it absolutely comes alive at 4000 rpm it's like a switch is thrown and you hear it working. It sounds like a demented leafblower! No joke , it is like this hollow whine that makes your hair stand up. Better if window is down though. Overall good product. To be honest, probably not worth the money, but not too much stuff is made for our trucks so we take what we can get and this is my hobby. Dyno tested at 230 hp to the ground with 3 inch lift and 32s. Believe the graph they give you. The gas mileage increase canceled out my lift and tires so about 2mpg in town. Was getting 16 now about 18 in town. If I took the lift and tires off I could probably get 20 with my bedcover down which is a great purchase as well (1-2mpg in town).