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

AEM Dryflow Filters increase power while protecting the engine from contaminants

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

The fully redesigned 2017 Audi A4 features an engine described by the editors of Car and Driver as “TFSI engine proved impressively torquey and willing to rev to its power peak, and while turbo lag is minimal, midrange throttle response is fabulous.” AEM can further supplement the performance of the 2017 Audi A4 with its 21-815C cold air intake kit, which adds another 11 horsepower to the 252 with which it left the Audi factory.

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 large AEM air box accomodates an oversized Dryflow air filter for increased power

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

The 21-815C intake system is a new design concept which allows for the full-assembled AEM replacement air box to simply be dropped in place of the OEM Audi unit. The air box is assembled outside the car and is then positioned in the engine compartment, utilizing only OEM mounting hardware. The AEM aluminum air box keeps hot engine air from entering the air intake system and directs cooler air to the filter using the factory inlet scoop.

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.

In most driving situations, a Dryflow filter doesn't require cleaning for up to 100,000 miles

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

Cleaning the Dryflow filter consists of an application of AEM 1-1000 synthetic air filter cleaner. The cleaner loosens and dissolves dirt and grime collected by the filter, after which the filter need only be rinsed with water, dried, and reinstalled. If you drive regularly in dusty or dirty conditions, your filter will probably require more frequent inspection and maintenance.

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


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