Why Upgrade Your Porsche 911 Exhaust?

Installing a performance exhaust system on your Porsche 911 is one of the most rewarding modifications you can make. Beyond the immediate weight reduction—factory systems often use heavy mufflers and restrictive resonators—an aftermarket exhaust liberates horsepower and torque while transforming the acoustic character of your flat-six engine. Brands like Eisenmann and Fabspeed represent two distinct philosophies: Eisenmann offers a refined, race-bred note with multiple sound profiles (Sport, Race, and Performance), while Fabspeed focuses on weight savings and maximum flow using high-grade T304 stainless steel and carbon-fiber options.

This guide covers the complete installation process, from preparation to final testing, whether you’ve chosen an axle-back, cat-back, or full turbo-back system. All steps apply to 991, 992, and earlier 997/996 chassis adapted for the specific models. Read through the entire guide before lifting your car to avoid surprises.

Tools & Materials Required

Gather everything beforehand to keep the job moving. The list below goes beyond basic wrenches to include items that solve common headaches like rusted fasteners or stubborn hangers.

  • Socket and ratchet set—metric 10mm, 13mm, 15mm, and 18mm (extensions and swivel sockets helpful)
  • Torque wrench (range 20-80 Nm)
  • Jack and four jack stands
  • Penetrating oil (e.g., PB Blaster or WD-40 Specialist)
  • Exhaust hanger removal tool or large flathead screwdriver
  • Pry bar for loosening stuck hanger bushings
  • Safety goggles and gloves
  • Anti-seize compound (copper or nickel-based)
  • New exhaust gaskets if your kit does not include them
  • O2 sensor socket (if your system requires sensor relocation)
  • Shop rags and degreaser for cleaning pipes
  • Needed exhaust system (Eisenmann or Fabspeed kit of your choice)

Preparation and Vehicle Lifting

Proper preparation prevents damage and speeds up the swap. Park the 911 on a level surface, engage the parking brake, and chock the rear wheels. For safety, disconnect the negative battery terminal—this is critical on newer 991/992 cars with electric parking brakes and electronic chassis controls that could engage unexpectedly. Remove the battery cover and use a memory saver if you prefer to keep radio presets and adaptations.

Jack the car at the central rear jack point (consult your owner’s manual) and place jack stands under the designated lift pads on the sill. Lower the car onto the stands and verify stability. If you need extra clearance, consider a QuickJack or ramp system. Never rely on a hydraulic jack alone.

Removing the Factory Exhaust

Loosen Fasteners While Cold

Spray all exhaust flange bolts, clamp fasteners, and O2 sensor bungs with penetrating oil. Allow 10–15 minutes for the oil to work. If bolts are severely corroded, use a breaker bar and apply heat with a propane torch (avoid heating near fuel lines or rubber components).

Disconnect O2 Sensors (if applicable)

On 991/992 cars with wideband sensors upstream and downstream, disconnect the sensor connectors carefully. Use an O2 sensor socket to remove the secondary sensors that may be threaded into the catalytic converters or mid-pipes. Label them to avoid confusion during reassembly. Fabspeed and Eisenmann kits often include sensor extension harnesses or bungs—ensure they are routed away from moving parts and exhaust heat.

Remove Exhaust Hangers and Clamps

Using a socket wrench, remove the bolts securing the exhaust hangers to the car body. The stock exhaust typically has three hanger points: one at the rear muffler, one at the center muffler, and one at the intermediate pipe. Pry the rubber bushings over the metal hooks with a screwdriver or hanger removal tool. If they are stuck, spray lubricant and work them loose with a pry bar. Do not cut the original hangers unless you are replacing them—they can be reused if in good condition.

Lower the Old System

Support the cat-back or axle-back section with a transmission jack or have a helper hold it. Remove the last clamps connecting the exhaust to the catalytic converters or headers. Slide the entire assembly rearward, tilting it downwards to clear the bumper valance. On some 911 models, you may need to remove the rear diffuser or lower bumper cover to access the mufflers. Place the old exhaust aside—consider selling it or recycling.

Installing the New Exhaust (Eisenmann or Fabspeed)

Test Fit Before Tightening

Before applying any final torque, do a dry fit of the new system. Lightly use spacers or washers if needed to center the tips in the cutouts. Both Eisenmann and Fabspeed offer adjustable tip positions—check alignment with both sides. Mark the position with a silver marker for later reference.

Install Gaskets and Connect Sections

Use new copper or graphene gaskets on all flange connections. Fabspeed typically uses flat gaskets with sealing grooves; Eisenmann often supplies metal gaskets. Apply a thin coat of anti-seize to all bolt threads to prevent galling and make future removal easier.

Connect the mid-pipes to the cats or headers, then slide the muffler assemblies onto the intermediate pipes. Hand-tighten the clamps and bolts. For clamp-style connections, ensure the slots are oriented downward so moisture cannot pool inside the pipe.

Hang the System

Slide the stock exhaust hanger bushings onto the new system’s mounting posts. If the new exhaust has different hanger points, use the supplied brackets (Eisenmann includes adapter brackets for some chassis). Lubricate the bushings with silicone spray to ease installation. Push the system up onto the hangers, ensuring no wires or lines are pinched. Tighten the hanger bolts to the factory torque spec (typically 25 Nm on the body-side studs).

Tighten All Clamps and Bolts

Now torque all fasteners to the manufacturer’s specifications. For typical 911 exhaust clamps: 40–50 Nm for M8 bolts, 60–70 Nm for M10 bolts. Check the supplied instructions for your specific kit. Use a torque wrench in the final pass. Over-tightening can deform flanges or strip threads.

Final Adjustments and Clearance Check

With the system hanging and loosely aligned, adjust the exhaust tips so they are centered within the bumper cutouts. Both Eisenmann and Fabspeed offer slotted brackets for tip movement. Once centered and parallel to the ground, lock the position by tightening the tip set screws.

Check all clearances: make sure the exhaust does not contact the heat shield, sway bar, driveshaft, or chassis. Crank the steering lock-to-lock (if the system runs near the steering linkage) and bounce the rear suspension a few times to simulate travel. Fabspeed systems are built with tight tolerances, but Eisenmann Race mufflers can be slightly larger in volume, so verify 1–2 inches of clearance from the rear bumper beam.

Reconnect Battery and Test

Reattach the negative battery terminal. Start the engine and let it idle. Listen for immediate leaks—a hissing or ticking sound indicates a gasket issue. Gradually rev the engine to 3000–4000 RPM while stationary to seat the new exhaust. Check for fumes inside the cabin—if present, tighten the header flanges or check for leaks.

Perform a visual underside inspection after the test run: look for smoke, wet spots near connections, or soot indicating a leak. Tighten any loose fasteners. Take the car for a short drive (5–10 miles) then re-check torque on all visible clamps. The heat cycles will expand and contract components, sometimes loosening hardware.

Break-in Period and Sound Evolution

Both Eisenmann and Fabspeed exhausts will change sound over the first 200–500 miles as packing material settles and carbon deposits form on the inner surfaces. During this period, avoid sustained high RPM or track use. You may notice the tone becomes deeper and louder as the system breaks in. Eisenmann Sport systems gain a more aggressive bark, while Race variants produce a raw, motorsport-inspired note. Fabspeed systems are known for their crisp, metallic sound that evolves into a refined rumble.

Troubleshooting Common Issues

  • Drone at highway speeds: Consider adding a Helmholtz resonator or J-pipe if the system produces excessive 2000–3000 Hz resonance. Fabspeed offers optional resonators; Eisenmann Race systems are designed for minimal drone.
  • Excessive vibration at the tips: Loose hanger bushings or misaligned tips. Replace rubber bushings with polyurethane units for better dampening.
  • Check engine light: If your system removed catalytic converters, you may need O2 sensor spacers, a tune, or sensor simulators. Eisenmann and Fabspeed sell de-cat versions, but check local emissions laws.
  • Rattling on startup: The exhaust may be contacting the heat shield. Bend the shield away or relocate the exhaust using the slotted brackets.

Additional Resources

For detailed model-specific tutorials, refer to the official installation guides from each manufacturer as well as trusted Porsche forums:

Conclusion

Upgrading your Porsche 911 to an Eisenmann or Fabspeed exhaust is a gratifying DIY project that delivers instant audible and performance feedback. By following methodical steps—from thorough preparation and careful removal to proper torque procedures and break-in monitoring—you can ensure a leak-free install that lasts for years. Whether you prefer the refined character of Eisenmann or the lightweight flow of Fabspeed, a well-installed performance exhaust transforms your 911 into the sports car it was always meant to be.