K&N parts matching AC Delco ACA21 air filter

The AC Delco ACA21 air filter cross references with the K&N air filter parts below. K&N offers compatible air filters for many AC Delco air filters giving you an alternative.
ProductPart NumberProduct Image 
K&N Replacement Air Filter
  • Designed to Increase Power
  • Million Mile Limited Warranty
Ojay Lewis, Connecticut
Today was the the first day I used the K&N air filter in my 2003 Maxima SE. I use my cruise control option every day on my drive back and froth to work. Going home from work my MPG went from 26 that I would normally get from the stock air filter to 30-31 MPG and going to work 34 to 38 MPG with the K&N. This air filter gives an extra 90 to 95 MPG per full tank of gas. Today the way the gas prices are going this was a big help me and my family. Thanks K&N!
Bob Lanson, Tarpon Springs, Florida
Filter was for my Infiniti G35 coupe and was installed with the help of a DIY video.
Rony, Illinois
Filter is a great product. My vehicle runs smoother and has new life to it.
33-2031-2 K&N 33-2031-2 Replacement Air Filter
List Price: $77.99
Your Price: $50.99