K&N Intake Systems: 4.6L 06+ Explorer & ST

[Carey Frennier]

Priced with bestoffer4 code @ performancepeddler.com



57-2573 FIPK 11.0 HP @ 4500 RPM $254.27 Shipped.



63-2573 Aircharger 11.0 HP @ 4500 RPM $274.19 Shipped.



77-2573KP 77 Kit 10.0 HP @ 4700 RPM $253.75 Shipped.



Basically the 57 and 63 series are the exact same unit. One has a different name so that it can be sold in California. The 57 Series is $20 less than the 63 series.



The 77 is their polished tube unit. It has the least amount of HP gain of the three.



Questions to K&N:

It says that the 63 series is the sister to the 57 Series. What does that mean?



What is the difference between 63-2573 and 57-2573?



Is one better than the other?



Their Answers:



The K&N 57-Series Generation 2 Fuel Injection Performance Kits and 63-Series Aircharger Performance Kits are, in most cases (this one included) the same product, and share the same components between the two systems. Fuel Injection Performance Kits (FIPKs) have been declared exempt by the California Air Resources Board, and carry a current and valid executive order (E.O.) number certifying them as legal for highway use in California, and states which recognize California emissions laws, for the vehicle applications each system is listed for. Aircharger Performance Kits are the same as Fuel Injection Performance Kits which have not yet been declared exempt by CARB.

 

[Tim Schey]

I have the 57-2573 for sale in the classifieds. Like new condition for $175 obo plus shipping.

 

[Bill Koonce]

I bought a FIPK for my '00 Mustang GT, and was sorely disappointed when the heavily reinforced flex-tube section absolutely refused to mate to the molded plastic part. The FIPK that I recently bought for my ST has a more user friendly sleeve fitting.



According to K&N and their fans, the molded plastic plenum is computer designed for optimal air flow. There may be some truth to this, as a simple pipe doesn't always promote laminar flow. My rule of thumb is "if it's chromed, it's for show, not go."



AFAIK the 63 series are "maximum effort" designs that are for off-road use, while the 57 series are for use where you might need to pass an inspection to get plates to drive on the road. In other words, if you race for money, the 63 series might be worth the tiny advantage it gives. :grin: