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K&N 57S-4000 Performance Intake Kit

57i Series Kits > Performance Intake Kit
Rating Star 1 Rating Star 2 Rating Star 3 Rating Star 4 Rating Star 5   4.9 out of 5 stars   12 Customer Reviews
  • Guaranteed to increase horsepower
  • Designed to improve torque and acceleration
  • Replaces entire factory air box and air filter system
  • Washable and reusable lifetime air filter
  • Easy to install, usually in 90 minutes or less
  • Lasts up to 100,000 miles before service is required (depending on driving conditions)
  • K&N Million Mile Limited Warranty
The K&N 57S-4000 Performance Airbox replaces the restrictive factory air filter and air box lid. K&N performance air boxes are designed to dramatically reduce air flow restriction as well as smooth and straighten air flow. This allows your engine to inhale a larger amount of air than the factory air filter assembly. More air means more usable power and acceleration throughout the engine’s RPM range. The 57S-4000 Performance Airbox comes with an oversized conical K&N high-flow air filter and an injection molded air box lid with the K&N logo embossed on top. The air filter can be used for up to 100,000 miles before servicing is needed depending on driving conditions. This performance air box is relatively easy to install into the air box base with commonly available tools. K&N builds these air box systems to last for the life of your vehicle and they are backed by K&N's Million Mile Limited Warranty. Some K&N 57S Series Performance Airboxes are compliant with the latest TUV emissions and sound regulations. Check the K&N catalog or website for vehicle applications and specific TUV status for each vehicle and air intake.

[More Information on K&N 57S Performance Airbox Systems]

Product Specifications

Air Filter ColorRed
Air Filter Height7.688 in (195 mm)
Air Filter MaterialCotton Gauze
Air Filter Outlet ShapeRound
California RestrictedNot legal for sale or use in California
Clamp MaterialStainless Steel
Clamp StyleRegular
Clamps IncludedNo Clamps Included
Product Box Height11.81 in (300 mm)
Product Box Length15.34 in (390 mm)
Product Box Width11.81 in (300 mm)
Product Style57i Series International Kits
Replacement FilterE-9289
Street Legal In All US States No
TUV Approved (Europe)See Application Link Above
TUV Certificate NumberTU-025979-C0-206
TypeGen I
Weight4.2 lb (1.9 kg)

K&N 57S-4000 Performance Intake Kit Product Reviews

Tuesday, August 16, 2016 - Part 57S-4000
The best purchase I have ever made, car feels, sounds and drives better. Had so many compliments on the car. It feels like a new vehicle with just this new kit. Great purchase and would recommend to all. Easy to install. Looks great!

Casey Raw
Exeter, United Kingdom
Wednesday, August 10, 2016 - Part 57S-4000
1s class service. Easy to install and sounds great.

Lee Brown
Sunderland, United Kingdom
Monday, July 25, 2016 - Part 57S-4000
2013 Focus ST I had watched numerous videos of lots of different applications from basic filters to full CAIS, so I knew what I was getting.The filter itself is top notch and the box lid does make noticeable improvement over stock, although patience is required when fitting as it is quite rigid. With this kit, I found personally that throttle response is improved and the performance sound is great, you actually get to hear the recirc valve now. I can't say that there is any difference in outright performance as I can't notice but over long runs the engine temp is cooler and takes less time to cool. I would recommend this kit 100% to anyone thinking of replacing stock.

Falkirk, United Kingdom
Saturday, June 18, 2016 - Part 57S-4000
Excellent product. Made a difference straight away - great sound and performance. Working well in my C-MAX

Aberdeen, United Kingdom
Thursday, May 19, 2016 - Part 57S-4000
This product is worth buying. My Focus ST 250 runs a lot smoother and got more power with this great K&N system, 10 out of 10 for this!!

Sheffield, United Kingdom
Saturday, November 14, 2015 - Part 57S-4000
I installed this intake on a 2015 Ford Focus Sedan SFE 1.0L EcoBoost. What a difference The kit is just a filter and a new intake box lid, so you won't get the loud CAI sound....but the throttle response is AMAZING MUCH more fun to drive, much smoother acceleration. Less bogging when the rpms dip too low. Couldn't be happier

Thursday, November 12, 2015 - Part 57S-4000
I really like the performance out of my 2015 Ford Focus with this Kit. I feel the kit is overpriced, However....Due to the fact, that all I would have required, in hindsight, would be to order the filter,the stock filter housing would work just fine with little or no modification.

Lynwood, Washington