$171.99 USD
MSRP $312.19 44.9% Off
Free Ground Shipping!
In Stock & Ready to Ship!
Find a Dealer

K&N 57S-4000 Performance Air Intake System

57i Series Kits > Performance Air Intake System
Rating Star 1 Rating Star 2 Rating Star 3 Rating Star 4 Rating Star 5   4.9 out of 5 stars   23 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 Air Intake System fits some Ford C-Max, Ford C-Max II, Ford Focus, Ford Focus II, Ford Focus III, Ford Focus RS, Ford Focus ST, Ford Focus XR5, Ford Grand C-Max, Ford Kuga, Ford Kuga II, Ford Tourneo Connect, Ford Transit Connect, Mazda 3, Mazda 5, Volvo C30, Volvo C70 II, Volvo S40 II, Volvo V40 Cross Country, Volvo V40 II, Volvo V50, and Volvo V70 III models. See vehicle applications link for details.
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

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

K&N 57S-4000 Performance Air Intake System Product Reviews

Saturday, March 10, 2018 - Part 57S-4000
Awesome filter easy fitting won't buy anything else.

Ian Forward
Wednesday, February 7, 2018 - Part 57S-4000
Had a issue with a different filter. Called technical support and spoke with Troy. Troy sent me this one and what a difference, the fit is perfect, the performance and sound is second to none. Troy went above and beyond to help to me out great customer service does still exist Make sure you ask for Troy for assistance. I would without hesitation refer family and friends. I now have K&N in all my vehicles and will here on out.

Las Vegas
Wednesday, January 24, 2018 - Part 57S-4000
Would give it 5 but for the cost - I can't get my head round why K&N don't actively sell the filter from this kit separately. The filter they sell separately doesn't have the open end and plug like this one. You can get it though - as a replacement part for this kit, so that's what I bought, and it fits with the standard air box lid perfectly. Anyways, it worked a treat for my mk3 ST petrol. A brilliant, cheap mod. Sounds a bit better but feels much better. I had a problem with a jerky throttle response which has all but disappeared. Feels like it revs higher more happily. Do it.

Saturday, November 25, 2017 - Part 57S-4000
Imagine a Grand C-max making turbo chirps as it passes you down the road. It has a standard eco boost engine but this air filter has completely changed the noise from weedy to meaty and now you can hear the turbo spooling and the standard blow off valve is much louder. The car also feels more powerful. Well pleased.

Nick Griffin
Chafford Hundred, United Kingdom
Thursday, August 24, 2017 - Part 57S-4000
Quick receipt. no problems getting it. Put this in the spouse's 2013 Focus ST. Got it used - 52,000 miles, so wanted to spruce it up. Very easy install. Installed the new one and tried it out. but feel was much better indicating a bit more torque. Nice sound. not real loud with the rubber seal in. Got about a mile or two better at about 25 mpg from 23.4 around town, low 30's on the road. I'm looking forward to removing the end piece when we go to the mountains. I figure it'll breath easier. The cover doesn't look as plasticy as the picture on K&N, it is a very close match to stock. Overall, very satisfied with the purchase.

Timothy Nygaard
Hanson, Kentucky
Thursday, June 29, 2017 - Part 57S-4000
Easy Installation, and very quick efficient delivery service.

Tim Saxon
Wetherill Park, Australia
Friday, June 23, 2017 - Part 57S-4000
Purchased this for my Focus ST diesel 2015 but unfortunately after 20 miles car went into limp mode on first two journeys made. Luckily I had kept the old filter which was refitted and car returned to normal. Technical department was quick to provide support and explained that this is due to the tight limits applied by Ford and that the settings would have to be changed to fix the problem. Wasn't keen to do this so asked to return and money was refunded quickly and without hassle. Unfortunately the cheque for return shipping I was offered has not turned up hence 4 stars.

Jason Loosley
Upper Heyford, United Kingdom