PRL Replacement High Volume Intake Oiled Cone Filter

PRL Replacement Oiled Cone Filter - 4" & 6" Inlet

Your PRL intake filter is washable and reusable, so most of the time you're cleaning it rather than replacing it. But eventually one gets damaged, contaminated beyond cleaning, or you'd just rather have a fresh one on hand than take the car off the road while the old one dries. This is that filter, in the two inlet sizes PRL uses across their Honda and Acura intake systems.

Which Size Do You Need?

Simple to sort out, and it depends on which intake you're running.

4" inlet (PRL-AF-4258) is the more common one. It's used in the 2018+ Accord 1.5T and 2.0T HVI, the 2016-2021 Civic 1.5T and 2.0 intakes, the 2017-2022 CR-V short ram, the 2022+ Civic 1.5T and 2.0 intakes, and the 2023+ Acura Integra 1.5T HVI.

6" inlet (PRL-AF-4315) is the Type R filter, used in the 2017+ Civic Type R FK8 and FL5 High Volume Intake systems.

If you're not sure, measure the inlet on your current filter or check which PRL intake is on the car. The two aren't interchangeable.

Why These Are Worth Buying Once

The whole point of an oiled cotton filter is that it isn't a consumable. Clean it, re-oil it, put it back. Done properly it lasts the life of the car, which means you stop buying disposable paper filters and stop sending them to a landfill.

So while this page exists for replacements, most people who buy one of these buy exactly one.

Grab A Cleaning Kit While You're Here

If you're replacing a filter, the one coming off is probably due for a clean anyway, and you'll want a spare in the rotation. Our PRL filter cleaning kit has the biodegradable cleaner and synthetic filter oil these are designed around.

Worth using the right stuff rather than improvising. Generic cleaners can damage the cotton, and the wrong oil in the wrong quantity is how people end up fouling a MAF sensor. The kit takes the guesswork out and it's cheap next to another filter.

More Filtration Surface, Not Less

Most high-flow filters make you trade filtration for airflow. PRL's approach avoids that.

The media is double-layer woven cotton with deep, dense pleats, and that pleating adds 10 to 15 percent more filtration surface than a shallower design. More surface means more air can pass through while the filter still catches particles down to 5 microns. You get the flow and you keep your engine protected, which matters on any turbocharged motor that's picky about what it ingests.

The cotton is encased in stainless steel mesh, so it resists dents and holds its shape rather than collapsing or tearing under real use.

The Rubber Base Is Better Than It Sounds

Worth understanding because it's a genuine difference in how these are made. PRL bonds the rubber base to the filter using a four-step, low-pressure injection molding process. Cheaper manufacturing methods let rubber seep into the media, and that seepage can block up to 25 percent of the airflow you paid for.

PRL's process essentially eliminates that, so you get the full flow area and a cleaner-looking filter. The flexible base also seals airtight, absorbs vibration, and holds up through millions of heat cycles.

The Oil Does Something Clever

There's real engineering in the lubricant. PRL's filter oil is sensor-friendly, so it won't foul your MAF the way over-oiling a cheap filter can. And it creates a positive magnetic charge, an ionic bond, with the stainless steel mesh.

That positive charge attracts negatively charged dust particles and holds them against the mesh before they reach the cotton. The practical result is that the cotton stays clearer for longer, so airflow stays consistent between cleanings rather than tapering off after the first few thousand miles.

Specifications

4" Inlet (PRL-AF-4258)

• Inlet: 4.00"
• Total height: 5.90"
• Filter height: 5.00"
• Flange height: 0.80"
• Base diameter: 4.50"
• Top cone diameter: 4.00"

6" Inlet (PRL-AF-4315)

• Inlet: 6.00"
• Total height: 5.00"
• Filter height: 4.50"
• Flange height: 0.75"
• Base diameter: 7.00"
• Top cone diameter: 4.00"

Fitment

4" inlet:
2016-2021 Honda Civic 1.5T and 2.0 intake systems
2017-2022 Honda CR-V short ram intake
2018+ Honda Accord 1.5T and 2.0T HVI
2022+ Honda Civic 1.5T and 2.0 intake systems
2023+ Acura Integra 1.5T HVI

6" inlet:
2017+ Honda Civic Type R (FK8 and FL5) High Volume Intake systems

Who Should Grab One

This is for the PRL intake owner whose filter has taken damage, gotten past the point of cleaning, or who just wants a spare so the car isn't sitting while one dries. It's the correct filter for your system rather than a generic cone that might fit, and it's built to last the life of the car once it's on. Match your inlet size, grab a cleaning kit if you don't have one, and drop it in.

Fits: PRL Motorsports intake systems, see the fitment list above. Sizes: 4" inlet (PRL-AF-4258) or 6" inlet (PRL-AF-4315). Media: double-layer woven cotton with stainless steel mesh, filters to 5 microns. Base: injection molded rubber, four-step low-pressure process. Maintenance: washable and reusable, use the PRL cleaning kit with biodegradable cleaner and synthetic filter oil.