How to Install an ISR Single‑Exit Exhaust on a G37 Sedan

Swapping the stock muffler for an ISR single‑exit system can give your Infiniti G37 a richer tone and a modest boost in performance. The job isn’t rocket science, but it does call for a bit of patience, the right tools, and a willingness to get your hands a little greasy. Below is a step‑by‑step guide that walks you through the process, from prepping the car to the final torque check.

What You’ll Need

• ISR single‑exit exhaust kit (including pipe, flange, and gaskets)
• Basic hand tools: socket set, wrench, torque wrench
• Jack and jack stands (or a lift)
• Penetrating oil (WD‑40 or PB‑Blaster)
• Rubber mallet
• Rag and clean‑up solvent
• Safety gear: gloves, safety glasses

Preparation: Safety First

Before you lift the sedan, make sure it’s parked on a flat surface and the parking brake is engaged. Disconnect the negative battery terminal to avoid any accidental shorts while you’re working around the exhaust.

Apply a liberal coat of penetrating oil to the factory exhaust bolts. Let it sit for at least ten minutes; this will make the stubborn nuts much easier to turn.

Step 1 – Lift the Car

Position a floor jack under the front subframe, then raise the vehicle until the front wheels are clear of the ground. Secure the car with jack stands placed under the pinch bolts—don’t rely on the jack alone.

Step 2 – Remove the Stock Exhaust

Start at the rear and work forward. Use a socket to remove the muffler clamps, then unbolt the hangers that support the pipe. When you reach the catalytic converter, you’ll likely need a breaker bar to loosen the bolts that have been tightened to factory torque.

Once all brackets are freed, gently lower the entire exhaust assembly and set it aside. A rubber mallet can help coax out any stubborn sections without bending the pipe.

Step 3 – Prep the Mounting Points

Clean the flange surfaces on both the car and the new ISR pipe. Any residue or old gasket material can cause leaks. A rag soaked in solvent does the trick without scratching the metal.

If the ISR kit includes new mounting brackets, compare them with the old ones. In most cases the stock brackets are reused, but double‑check the holes line up perfectly.

Step 4 – Install the ISR Pipe

Slide the ISR pipe into place, making sure the single exit aligns with the rear of the sedan. Fit the new gaskets onto the flange, then hand‑tighten the bolts. Follow the kit’s torque specifications—typically around 30 Nm for the flange bolts.

Reattach the hangers using the original bolts. If the kit provides upgraded hangers, install them now; they often feature a softer rubber bushing that reduces vibration.

Step 5 – Connect the Tailpipe

The ISR system’s single exit usually ends in a flared tip. Align the tailpipe with the exhaust flange, insert the gasket, and tighten the bolts in a criss‑cross pattern. This ensures even pressure and a leak‑free seal.

Step 6 – Check Everything

Before you lower the car, give each bolt a final torque check. Verify that the exhaust isn’t rubbing against any suspension components or the under‑body. A quick visual inspection can save you from rattles later on.

Step 7 – Lower the Car and Test

Remove the jack stands, lower the G37 gently, and reconnect the negative battery terminal. Start the engine and listen. You should hear a deeper, more resonant note, and the exhaust should feel firm when you place a hand near the pipe (watch the heat!).

If you notice any rattling or a faint hissing sound, re‑inspect the bolt torques and gasket seating. A minor adjustment now prevents headaches down the road.

Troubleshooting Tips

• Leaking at the flange? Re‑apply gasket and tighten to spec.
• Exhaust rattles? Ensure all hangers are snug; consider adding a silicone heat‑shield.
• Engine back‑fires? Double‑check that the oxygen sensor connections are intact; sometimes the sensor plug can get nudged during removal.

Final Thoughts

Swapping to an ISR single‑exit exhaust is one of the more rewarding DIY projects for a G37 owner. It’s a blend of modest performance gain, a sportier sound, and a sense of accomplishment that only a hands‑on upgrade can bring. Take your time, follow the torque specs, and you’ll enjoy the new tone every time you hit the road.