Why Upgrade to an AWE Tuning Intake on Your B9 S4?

Your Audi B9 S4 comes from the factory with a capable but restrictive air intake system. The AWE Tuning Intake is a popular aftermarket upgrade that replaces the stock airbox and snorkel with a free-flowing, high-quality cold air intake. The primary benefits include a noticeable increase in intake sound—a more aggressive growl under acceleration—and a modest gain in horsepower and torque, typically 10–15 wheel horsepower when paired with a proper tune. The intake also reduces intake air temperature by pulling air from outside the engine bay, which can mitigate power loss on hot days. Additionally, the AWE intake uses a reusable, washable filter, saving you money on replacement filters over time. The kit is engineered specifically for the B9 S4 (3.0T) and includes all necessary hardware, CNC-machined brackets, and a silicone coupler for a precise fit. This guide will walk you through the complete installation process, from prepping your workspace to verifying the install after a test drive.

Tools and Materials Needed

Gather all tools and components before starting. The AWE Tuning Intake kit contains the main intake pipe, heat shield, filter, clamps, brackets, and fasteners. You will also need:

  • Socket set (metric, primarily 10mm and 13mm)
  • Torque wrench (capable of low torque values like 30–55 in-lbs)
  • Flathead screwdriver (for prying clips and loosening band clamps)
  • Phillips screwdriver (for removing a few factory screws)
  • Ratchet and extension bar (a 6-inch extension helps reach lower bolts)
  • Trim removal tool (optional, but useful for popping plastic clips without breaking them)
  • Shop towels (for cleaning spillage or wiping the engine bay)
  • OBD-II scanner (to check for any post-installation codes)

It is also recommended to have a flashlight, a magnetic pickup tool (in case you drop a fastener), and some lubricant for the silicone coupler if it is tight (soapy water works).

Preparation Steps

Proper preparation prevents mistakes. Park your vehicle on a level surface and allow the engine to cool completely—the intake manifold and rubber hoses can be hot. Disconnect the negative battery terminal to prevent any accidental electrical shorts or activation of the electronic throttle body while you are working near sensors. Use a 10mm socket to loosen the battery clamp, then tuck the terminal away from the post. Set your parking brake and consider using wheel chocks for added safety. Read the AWE Tuning installation manual that came with your kit; while this guide covers the same steps, each kit variant (with or without sound enhancement) may have minor differences. Finally, clear the area around the engine bay—remove any loose items from the strut tower brace or cowl area.

Understanding the B9 S4 Engine Bay Layout

Before you start removing parts, familiarise yourself with the stock intake system. The B9 S4 uses a dual-path intake: the main air filter box sits near the right (passenger side) of the engine, connected to a snorkel that extends to the front grille area. The mass airflow (MAF) sensor is integrated into the intake tube just after the filter box. A large rubber hose connects the intake tube to the throttle body. The AWE intake replaces the entire assembly from the filter box to the throttle body, using a larger diameter tube and a conical filter. Note the location of the MAF sensor connector—it is a grey or black clip near the top of the intake tube. Also identify the breather hose from the engine cover that connects to the intake; you may need to disconnect it.

Removing the Stock Intake System

Begin by carefully removing the plastic engine cover. It is held by four rubber grommets; pull upward firmly at each corner. Set it aside. Using a flathead screwdriver, loosen the band clamp between the intake tube and the throttle body (the large rubber elbow on the driver’s side of the intake manifold). Do not remove the clamp completely yet—just loosen it enough to separate the hose later. Next, disconnect the MAF sensor electrical connector: press the tab on the connector and pull it apart. Do not yank on the wires. Use a trim tool or your fingers to release the wiring harness from any plastic clips attached to the intake tube. Now loosen the clamp at the front end of the intake tube where it connects to the filter box. You will likely need to remove the two T25 torx screws (or plastic clips) that hold the filter box upper cover to the lower housing. Lift the air filter lid and remove the factory filter element.

Remove the snorkel that feeds air to the filter box from the grille. It is usually held by a few T25 screws or push clips. Work it out carefully—it may be tight against the hood latch reinforcement. With the snorkel free, you can now lift the entire stock intake assembly (lower box, tube, and filter) out of the engine bay. Some vehicles have a small vacuum line attached to the intake tube; disconnect it after loosening its clip. Remove any remaining screws or bolts securing the lower intake box to the chassis (usually a 10mm bolt at the bottom). Set all factory parts aside.

Installing the AWE Tuning Intake

Mounting the Heat Shield and Filter

Start by installing the CNC-machined bracket that holds the AWE heat shield. Align it with the factory mounting points on the passenger side of the engine bay. Using the provided hardware, loosely fasten the bracket with a 10mm socket. Do not tighten fully until the heat shield is positioned. Slide the AWE heat shield into the bracket slots and secure it with the included bolts. Adjust the shield so it sits flush against the inner fender and seals against the hood when closed. Torque the bracket bolts to approximately 55 in-lbs (as specified in the AWE manual).

Connecting the Intake Tube and MAF Sensor

Now take the AWE intake pipe. If your kit includes a separate MAF sensor housing adapter, install the MAF sensor into it first. Carefully transfer the MAF sensor from the stock tube—it is held by two T20 Torx screws. Make sure the sensor’s orientation is correct (the arrow should point in the direction of airflow). Use the provided o-ring or gasket and gently seat the sensor. Tighten the Torx screws to 15-20 in-lbs. Slide the silicone coupler over the throttle body opening (the metal inlet on the intake manifold). Use the supplied band clamp but do not tighten yet. Fit the intake pipe onto the silicone coupler and adjust its position so that the filter fits neatly inside the heat shield. The pipe should clear the engine cover mount and the coolant reservoir. Once aligned, tighten both coupler clamps: first the throttle body side, then the MAF side. Torque to 35-40 in-lbs to prevent leaks but avoid over-tightening that could deform the silicone.

Attaching the Filter and Final Checks

Slide the AWE conical filter onto the end of the intake pipe (the MAF sensor will be downstream if you mounted it correctly—confirm that the filter is on the ambient air side). Secure it with the provided clamp. Ensure the filter sits well inside the heat shield and is not rubbing against any hot surfaces or moving parts. Connect the MAF sensor electrical connector—you should hear a click. Reattach any vacuum lines that originally connected to the intake, if applicable. Some B9 S4s have a small breather hose that needs to be connected to a port on the intake pipe; cap it if the AWE kit provides a cap. Reinstall the factory engine cover if it clears the new intake (it may require a slight trim, but typically the AWE intake fits under the cover).

Common Installation Challenges and How to Overcome Them

During installation, you may encounter a few common issues. The MAF sensor connector can be stubborn—use a small flathead to gently release the locking tab before pulling. If the silicone coupler is too tight, dip it in hot water for a few seconds to soften it. When aligning the intake pipe, ensure it does not pinch any wiring harnesses or hoses underneath. Some owners find that the heat shield bracket needs slight adjustment to avoid contact with the inner fender liner. If the hood does not close fully, check that the heat shield is not sitting too high; you can slightly loosen the bracket and reposition it. Finally, if you have an aftermarket strut tower brace, you may need to modify your brace or purchase a compatible brace kit from AWE or another manufacturer. Always refer to the official AWE instruction sheet for torque specs and troubleshooting.

Post-Installation Steps and Verification

After everything is tightened, reconnect the negative battery terminal. Double-check all clamps, the MAF sensor connection, and that no loose tools are in the engine bay. Start the engine. The idle should settle quickly; listen for any whistling or hissing sounds that indicate an air leak. Common leak points are the coupler at the throttle body and the MAF sensor housing. If you hear a hiss, carefully tighten the affected clamp a bit more. Let the engine reach operating temperature, then gently rev it. The intake sound will be noticeably louder—this is normal. Take a short test drive of about 10 minutes, monitoring for any check engine light illumination. Use an OBD-II scanner to check for pending codes. The most common code after intake installation is a lean code (P0171) if there is a vacuum leak. If no codes appear, you are good to go. AWE recommends a performance recalibration of the ECU for maximum gains, especially if you have other modifications. Consider a stage 1 tune from a reputable tuner like Unitronic or 034Motorsport to fully exploit the increased airflow.

Maintenance of Your AWE Intake

The AWE filter is a dry or oiled type depending on your kit variant. Dry filters can be cleaned using a vacuum and then washed with mild soap and water every 15,000–20,000 miles. Oiled filters require a cleaning kit. Never over-oil the filter as excess oil can contaminate the MAF sensor. Inspect the filter every oil change for debris. Silicone couplers can degrade over time; check for cracks around the heat cycle areas. The heat shield is powder-coated and can be wiped clean with a damp cloth. Keeping the intake system clean ensures consistent performance and protects the engine from dirt ingestion.

Conclusion

Installing the AWE Tuning Intake on your B9 S4 is a straightforward afternoon project that transforms the driving experience. The increased intake roar, combined with modest power gains and reduced intake air temperatures, makes it one of the best value upgrades for the 3.0T engine. By following this step-by-step guide, you have equipped your vehicle with a high-flow induction system that looks and sounds professional. Remember to verify all connections, test for leaks, and consider a complementary ECU tune to unlock the full potential. Enjoy the enhanced performance and the unmistakable sound of your Audi S4 breathing freely.