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K&N 57S-4000

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   8 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-B0-206
TypeGen I
Weight4.2 lb (1.9 kg)

K&N 57S-4000 Product Reviews

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
Tuesday, November 10, 2015 - Part 57S-4000
All my vehicles are equipped with K&N products. This performance kit was no different, excellent build quality and easy to install. Shipping was very fast and the ordering process is always easy.

Ross Macdonald
Ontario, Canada
Tuesday, August 4, 2015 - Part 57S-4000
It is very easy to install, just take the original airbox cover off, replace the old filter with the new one and bolt the new airbox cover on with the original screws. Takes all of about fifteen minutes. Works great.

Tom Hudson
Rockford, Illinois
Thursday, April 2, 2015 - Part 57S-4000
Very easy to fit to my Volvo C30 RDesign. Immediately smoother through the rev range and better fuel consumption. Wish I had fitted earlier.

Thursday, July 24, 2014 - Part 57S-4000
I tried the kit 57S-4000 with exchange filter from K&N with the new lid for the air box. Just looking at the product and thinking about the idea of putting in a bigger filter by making a new bigger lid of the air filter is in my world is brilliant. The work putting it on was super easy and with good fittings, and with an easy manual. The performance was noticeably better through all the revs. And the best part of all was that the fuel consumption went down below the car manufacturer’s data. This kit cost a lot, but it really works and it will save you fuel, and by the time it will actually pay it self off. I recommend this K&N kit to all Volvo V40 D2 owners.

Andreas Roger Consitt
Sweden / Lund