AEM 21-827C Cold Air Intake System

Why it's worth it

The AEM 21-827C pairs low-restriction aluminum tubing with a heat shield and AEM's oil-free Dryflow filter, which the company rates for up to 100,000 miles before it needs cleaning. It's the pick if you want the performance without the oiling ritual.

The dry filter is the whole argument. AEM's Dryflow media traps grit mechanically, with no oil anywhere in the system, so there's nothing to migrate onto your MAF sensor. AEM rates it for up to 100,000 miles before it even needs washing, depending on how dusty your driving is. You wash it, you dry it, you put it back. For anyone running a turbo, skipping filter oil entirely is the cautious call.

The heat shield has edge trim, which is a small detail that matters. That lining lets the shield seat against the hood or fender without buzzing or wearing a shiny spot into your paint. Combined with the mandrel-bent aluminum tube, you get a kit that looks installed rather than added on. Aluminum also holds its shape better than plastic tubing when the engine bay gets hot on a long climb.

From our review of 5 cold air intakes, by Ben Carter, Tech Editor

What we like

• +The dry filter is the whole argument
• +The heat shield has edge trim, which is a small detail that matters
• +Tuners like AEM for a reason
• +AEM keeps one of the deepest CARB exemption catalogs in the aftermarket

What to know

• –Peak gains sit in the middle of the pack
• –Some fitments use an open or half-enclosed shield
• –Replacement Dryflow elements are harder to grab locally