How to Install an Apr Audi Rs5 Performance Exhaust for Enhanced Sound and Power

Why Upgrade to an APR Performance Exhaust?

The Audi RS5 is already a formidable machine, but the factory exhaust system is often designed to balance sound, emissions, and cost. An APR performance exhaust is engineered to unlock more aggressive exhaust notes and reduce backpressure, which can translate into noticeable horsepower and torque gains. Beyond the raw performance increase, the sound profile becomes deeper and more refined—a hallmark of the RS5’s 2.9L or 4.2L V6/V8 engines. APR’s systems are backed by extensive research and development, ensuring that you get a product that integrates seamlessly with the vehicle’s engine management and emissions components.

Before diving into installation, it’s essential to understand what you’re getting. APR offers several exhaust configurations for the RS5, including cat-back, axle-back, and full turbo-back systems. Each option provides different levels of sound enhancement and power gains. For most enthusiasts, a cat-back exhaust is the sweet spot—it replaces everything from the catalytic converters back, delivering a noticeable sound improvement and a modest power bump without the need for a tune. If you’re planning to pair it with an ECU upgrade, a full turbo-back system maximizes gains but may require additional modifications for emissions compliance.

Tools and Materials Needed

Having the right tools on hand before you start will save time and frustration. While the specific hardware may vary based on the APR kit you purchased, the following list covers the essentials for a typical cat-back install:

APR performance exhaust system (cat-back or turbo-back, depending on your kit)
Jack and jack stands (or a vehicle lift)
Socket set (metric, typically 10mm, 13mm, 15mm, and 18mm)
Wrenches (combination wrenches in the same sizes)
Torque wrench (to tighten bolts to spec)
Cutting tool (e.g., reciprocating saw or angle grinder with a metal-cutting blade, if factory exhaust needs sectioning)
Safety glasses and gloves
Penetrating oil (e.g., WD-40 or PB Blaster) for stubborn bolts
Exhaust hanger removal tool (or pry bar to pop off rubber hangers)
Oxygen sensor socket (if reusing factory sensors)
Anti-seize compound (for reuse of sensor threads)

Double-check your APR kit contents. Some systems include clamps, gaskets, and hardware; others may require you to reuse factory brackets or gaskets. If anything is missing, contact APR support before proceeding.

Preparation Steps

Proper preparation is critical for a safe and smooth installation. Follow these steps in order:

Choose a level workspace – Concrete garage floor or driveway. Ensure the area is well-lit and free of clutter.
Engage the parking brake and place wheel chocks in front of the front wheels.
Lift the vehicle – Using a floor jack, raise the rear of the car and place jack stands under the factory pinch weld jacking points. Make sure the car is stable. Never work under a vehicle supported only by a jack.
Protect yourself – Wear safety glasses to guard against debris and gloves to avoid cuts from sharp exhaust edges or hot components.
Allow the exhaust to cool if the car has been driven recently. A hot exhaust can cause burns and make hardware removal more difficult.
Apply penetrating oil to all exhaust flange bolts, hanger bolts, and any oxygen sensor threads (if present) to ease removal.

Removing the Stock Exhaust

The OEM exhaust system on the RS5 is a single unit from the catalytic converters to the rear mufflers. Removing it requires careful attention to hangers and flanges. Here’s a detailed step-by-step:

Locate the rear exhaust hangers – There are typically four to six rubber hangers on the rear section. Use a hanger removal tool or a pry bar to disconnect the rubber isolators from the metal exhaust hangers. Take care not to tear the rubber.
Unbolt the mid-pipe hanger (if present) – Some RS5 models have a bracket near the center support bearing. Remove the 13mm or 15mm bolt holding it to the chassis.
Disconnect the exhaust flanges – Locate the connection behind the catalytic converters. This is usually a slip joint or a bolted flange with two nuts (18mm). Use a socket and ratchet to loosen and remove them. If the bolts are rusted, apply more penetrating oil and allow it to soak.
Cut the stock exhaust if needed – The factory system may be too long to slide out in one piece. Using a reciprocating saw with a metal blade, cut the exhaust pipe at a convenient point (e.g., between the rear axle and the muffler). Wear ear protection and work slowly to avoid damaging nearby components.
Remove the oxygen sensors – If your vehicle has sensors in the factory exhaust (post-cat), carefully unscrew them using an oxygen sensor socket. Keep them clean; they will be reused in the APR system.
Lower the stock exhaust – With all hangers and flanges free, slide the exhaust sections out from under the car. You may need to wiggle the system past the rear axle and suspension components. Having a helper is beneficial here to avoid scratching the undercarriage.

Once the stock exhaust is removed, take a moment to inspect the rubber hangers. If they are cracked, dry, or stretched, replace them with fresh OEM or aftermarket hangers. Worn hangers can cause the new exhaust to sag or rattle.

Installing the APR Performance Exhaust

Now the fun begins. APR designs its exhaust systems for a direct fit, but you must still align everything carefully. Follow these steps:

Prepare the APR components – Lay out all the pipes, mufflers, and hardware. Verify that each piece corresponds to the right location (e.g., driver vs. passenger side, front vs. rear section). Some systems use a band-clamp design; others use V-band clamps or bolted flanges.
Install the front pipe (if included) – For a cat-back system, this is the section from the catalytic converters to the center muffler. For a turbo-back, it includes the downpipe. Bolt it loosely to the factory flange using new gaskets (supplied or recommended by APR). Do not fully tighten yet.
Attach the mid-section – Slide the next pipe into place, connecting it via the clamp or flange. Use anti-seize on the threads of bolts to ease future removal. Again, only snug them.
Position the rear muffler sections – Lift the muffler boxes into place and attach them to the mid-pipe. Connect the hangers to the factory rubber isolators. If the APR system uses new hangers or brackets, install those now. Ensure the exhaust tips are centered in the bumper cutouts.
Reinstall the oxygen sensors – Thread the sensors into the APR bungs (they may be located in different positions than stock). Apply a small amount of anti-seize to the threads. Torque to the manufacturer’s specification (usually around 30–35 lb-ft, but verify).
Torque all connections – Starting from the front and working to the rear, tighten all bolts and clamps to the torque values specified in the APR instructions. For band clamps, this is typically 30–40 lb-ft. For flange bolts, 40–50 lb-ft. Use a torque wrench for consistency.
Check clearances – Rotate the steering full lock (if working near the front) and bounce the rear suspension to simulate road movement. Ensure no part of the exhaust contacts the underbody, heat shields, or driveline. Adjust hanger positions if needed.

A common pitfall is having the exhaust too tight to the chassis, which can cause vibrations and heat transfer. Leave a small gap (about ¼ inch) between the pipe and any frame rail or heat shield.

Final Checks and Testing

After all bolts are torqued and the system is aligned, perform these checks before lowering the car:

Double-check all clamps and bolts – Go around the entire system once more. Loose connections can cause leaks, rattles, or loss of horsepower.
Verify sensor wiring – Ensure oxygen sensor cables are routed away from exhaust heat and moving parts. Zip-tie them to factory brackets if necessary.
Lower the vehicle – Remove the jack stands and lower the car to the ground. Do not drop it abruptly; lower evenly.
Start the engine – With the car in park and the parking brake on, start the engine and let it idle. Listen for any hissing sounds (indicating a leak) or metallic rattles. If you hear a leak, tighten the nearest clamp or flange.
Warm up the system – Let the engine reach operating temperature. The exhaust will expand slightly; some systems may need a re-torque after the first heat cycle.
Take a test drive – Drive the car gently for the first few miles, then gradually increase throttle. Pay attention to drone inside the cabin (some resonance is normal but excessive drone may indicate a loose component). Note the sound at different RPM ranges. The APR exhaust should produce a deep, aggressive note without being obnoxious during highway cruising.

If you notice any check engine light (CEL) related to the oxygen sensors or emissions, double-check that all sensors are properly connected and that there are no exhaust leaks upstream of the sensors. Some APR systems come with a bung extender to move the sensor slightly out of the direct exhaust stream; if included, install it.

Performance Gains and Sound Profile

Installing an APR exhaust does more than just change the sound. On a stock RS5, a cat-back system can yield an increase of 8–12 horsepower and 10–15 lb-ft of torque, depending on the specific version and engine. When paired with an APR ECU tune (stage 1 or 2), the combined gains can exceed 30–40 horsepower. The reduced backpressure allows the engine to breathe more freely, especially in the upper RPM range. You’ll feel a sharper throttle response and a more linear power delivery.

Sound-wise, the APR exhaust eliminates the muffled, subdued note of the factory system. The exhaust tips are significantly larger—usually 102mm or 103mm in diameter—giving the rear a more aggressive stance. Inside the cabin, the Soundaktor (if equipped) may amplify the new exhaust note; you can adjust it via your vehicle’s drive mode settings. Many owners report that the APR system adds a deep, European “bark” on startup and a smooth, throaty roar under acceleration without excessive droning.

Maintenance and Long-Term Care

To keep your APR performance exhaust in top condition, follow these tips:

Inspect clamps and hangers every 5,000 miles – Vibrations can loosen hardware over time. Re-torque as needed.
Clean the exhaust tips regularly – Use a non-abrasive metal polish to remove carbon buildup and road grime. This prevents pitting and maintains the polished appearance.
Check for leaks – After every few months, listen for any changes in sound that could indicate a small leak at a joint. Soapy water applied to connections can help spot bubbles.
Address rust immediately – If you live in a region that uses road salt, consider applying a heat-resistant spray coating to the underside of the exhaust (avoid sensors and bungs). APR systems are made from T304 stainless steel, which resists corrosion well, but salt can still attack welds over time.

Common Issues and Troubleshooting

Even with a quality product, installation can present challenges. Here are common issues and solutions:

Issue	Likely Cause	Solution
Exhaust hitting the driveshaft or frame	Improper alignment or damaged hangers	Loosen all clamps, adjust position, retighten. Verify hangers are seated correctly.
Drone at cruising speeds ( >2000 RPM )	Exhaust resonance; missing resonator or muffler	Check that all supplied resonators are installed. Some kits include a Helmholtz resonator to cancel drone.
Check engine light (P0420, P0430)	Oxygen sensor reading incorrect; exhaust leak before sensor	Inspect sensor bung position. If too far from catalytic converter, use a spacer. Ensure no leaks upstream.
Rattling at idle	Loose heat shield or pipe touching underbody	Tighten all exhaust connections; bend heat shields away (if safe).

Conclusion

Upgrading to an APR performance exhaust transforms your Audi RS5’s driving experience. The deeper, more aggressive sound and the measurable power gains make every commute or canyon run more engaging. By following the detailed steps above—from gathering the right tools to performing final checks—you can install the system yourself with confidence. Remember to take your time, torque everything to spec, and don’t hesitate to consult APR’s official instructions or a professional shop if you encounter unusual obstacles.

For more information on APR’s product line and to verify compatibility with your specific RS5 model year, visit APR’s official website. You can also find helpful installation tips and owner experiences on forums like Audizine and AudiWorld. Always follow local emissions regulations when modifying your vehicle.