Distinctive AEM Cold Air Intake Kit Adds Horsepower to 2017 Audi A4

The AEM 21-815C intake for Audi A4 provides a larger air box to fit an oversized Dryflow filter

The turbocharged four-cylinder engine is comprised of a cast-iron block and aluminum cylinder head. The valvetrain is of a double overhead camshaft (DOHC) configuration, with four valves per cylinder controlled by the Audi valvelift system. A bore of 82.5 mm and a stroke of 92.8 mm provides a displacement of 1984 cc, rounded up to 2.0 L. The 2017 A4 engine produces 252 horsepower and 273 lb-ft of torque.

The 21-815C has been developed by AEM engineers to take advantage of Audi’s use of forced induction. As the Audi A4 is turbocharged, it has a greater capacity for increased horsepower over normally-aspirated engines. By packing the turbocharger to capacity with cool, fresh intake air the engine’s Electronic Control Unit (ECU) will respond by adding more fuel. The equation is simple: more air plus more fuel equal more power.

If you’re familiar with turbocharged engines you recognize that the act of compressing the intake air heats it up considerably, as a function of how much the turbocharger pressurizes the incoming air. Internal combustion engines work best with cool intake air, so an intercooler is typically installed between the turbocharger and the intake ports. A cold air intake system actually assists your engine’s intercooler, as it delivers cooler air to the turbocharger, the output of which is lower in temperature, supplementing the drop in intake temperature the intercooler is designed to deliver.

The AEM air box is assembled outside the car for simple and easy installation using OEM hardware

The filter itself is an oversized AEM 21-209DK Dryflow filter with a 7.5” base diameter. The Dryflow filter is constructed of an innovative high-performance synthetic filter material. The washable, non-woven oil-free synthetic filter medium has been specified for its ability to deliver high air flow, excellent filtration, and improved performance. In fact, a Dryflow filter captures up to 99% of harmful contaminants before they can reach your engine.

While AEM Dryflow air filters typically do not require service until after about 100,000 miles of normal driving, a window is provided through which you can inspect the filter at any time. There’s also an AEM logo burnished on the window, so when your raise the hood on your A4 at the next Saturday morning “Morning Beverage and Motors” get-together everyone present will recognize you’re serious about performance.

Despite the fact that the air box needs to be assembled outside the car, the construction and installation of the AEM 21-815C cold air intake is a relatively straightforward DIY modification. The entire process should take just a few hours to install with just a few common hand tools you probably already own. The AEM 21-815C utilizes only the factory mounting locations, so there are no holes to drill or permanent modifications to make.

The tapered cylinder shaped AEM Dryflow air filter is made from an oil-free, synthetic filter media

The AEM 21-815C is designed to fit the following vehicles:

2017 AUDI A4 QUATTRO 2.0L L4 Fuel Injection - All Models
2017 AUDI A4 2.0L L4 Fuel Injection - All Models