Introduction to the GReddy Supreme SP GT-R Exhaust

Upgrading the exhaust system on a Nissan GT-R is one of the most effective ways to unlock additional horsepower, reduce weight, and transform the car’s acoustic character. The GReddy Supreme SP series is engineered specifically for the R35 platform, offering a blend of high-quality materials, precision fitment, and a refined sound profile that avoids the drone common with cheaper aftermarket setups. This step-by-step guide walks you through the entire installation process, from gathering the right tools to performing the final test drive. Whether you are a seasoned DIYer or a first-time modifier, following these instructions will help you achieve a professional-grade result while avoiding common pitfalls.

Benefits of the GReddy Supreme SP Exhaust

Before diving into the installation, it pays to understand what makes this exhaust system stand out. The Supreme SP features full T304 stainless steel construction with mandrel-bent tubing for consistent internal diameter and maximum flow. The polished tips add a visual upgrade, while the integrated Helmholtz resonators cancel out unwanted frequencies in the cabin. Expect gains of 15–25 hp and a weight reduction of approximately 30–40 pounds compared to the factory system. The sound is aggressive under full throttle but remains civil during cruising, making it an excellent choice for daily-driven GT-Rs.

Tools and Materials Needed

Having the correct tools on hand before you lift the car will save time and frustration. Below is a comprehensive list of everything required for a smooth installation.

  • GReddy Supreme SP GT-R Exhaust System – Verify you have received all components: front pipes, mid-pipes, muffler section, hardware bag, and new gaskets.
  • Socket set – Metric sockets from 10mm to 19mm, including deep sockets for longer studs.
  • Wrench set – Combination wrenches for tight spaces, particularly 14mm and 17mm.
  • Torque wrench – Essential for tightening bolts to factory specifications to prevent leaks or stripped threads.
  • Jack and jack stands – A low-profile jack and four sturdy jack stands rated for the GT-R’s weight (minimum 3-ton capacity).
  • Penetrating lubricant – WD-40, PB Blaster, or similar to break loose rusted fasteners.
  • Oxygen sensor socket – For removing and reinstalling O2 sensors if your setup requires relocating them.
  • Cutting tool – A reciprocating saw or angle grinder with a cutting wheel may be necessary if the old exhaust has seized bolts or welded sections.
  • Safety goggles and gloves – Protect your eyes from debris and hands from sharp edges and hot surfaces.
  • Lubricant for rubber hangers – Silicone spray or dish soap to ease hanger removal and installation.
  • Shop rags and degreaser – Clean any oil or dirt that accumulates during removal.
  • New exhaust gaskets – Even though the GReddy kit includes gaskets, having spares from Nissan ensures leak-free sealing.
  • Exhaust hanger removal tool – A specialized tool makes removing the stubborn rubber isolators much easier.
  • Helper – An extra set of hands is invaluable when aligning and hanging the new sections.

Preparation Before You Start

Taking the time to prepare the work area and the vehicle prevents unnecessary delays and ensures safety throughout the job.

  • Work on a flat, level surface. A garage floor or paved driveway is ideal. Avoid gravel or uneven ground where the jack could tip.
  • Engage the parking brake. Even though the car will be on jack stands, always use the brake as a secondary safety measure.
  • Disconnect the negative battery terminal. This prevents any accidental electrical shorts, especially if you will be working near the O2 sensors or wiring.
  • Let the vehicle cool completely. The factory exhaust gets extremely hot. Allow at least two hours after driving to avoid burns.
  • Check for clearance. Ensure the jack and stands have adequate access to the factory lift points. The GT-R has designated jack points at the front crossmember and rear diff housing.
  • Prepare penetrating oil. Spray all exhaust nuts and bolts with your chosen lubricant 30 minutes before beginning work. This gives the chemical time to penetrate rust and corrosion.

Removing the Factory Exhaust System

With the vehicle safely raised and secured on jack stands, you can begin removing the stock exhaust. Work systematically from front to rear to avoid unnecessary strain on the system.

Step 1: Remove the Rear Exhaust Section

Starting at the muffler section, locate the bolts that connect the rear exhaust to the mid-pipes. On an R35 GT-R, there are typically two flanges held by four 14mm bolts each. Use a socket wrench and penetrating oil if they are stubborn. Once the bolts are removed, support the muffler with one hand while pulling the rubber hangers off their studs. A silicone spray on the hangers makes this step much easier. Lower the muffler slowly and set it aside.

Step 2: Disconnect the Mid-Pipes and Front Pipes

The mid-pipes run from the rear muffler to the front catalytic converters. There are additional hangers along the transmission tunnel that need to be freed. Continue removing bolts and hangers, working your way forward. The front pipes (often called downpipes on the GT-R) attach directly to the turbocharger outlets. These connections have O2 sensors that must be unplugged. Disconnect the sensor wiring harness clips, then unscrew the sensors using an O2 sensor socket. If the sensors are seized, apply penetrating oil and allow extra time. Once the sensors are free, remove the remaining bolts that secure the front pipes to the turbos. There are typically four 12mm bolts per side. Carefully lower the entire factory exhaust assembly out from under the car.

Step 3: Inspect and Clean

With the old system removed, use this opportunity to inspect the turbo flanges for any exhaust leaks or gasket remnants. Clean the mounting surfaces with a rag and degreaser. Check the condition of the rubber hangers – if they are cracked or stretched, replace them with new ones from Nissan to ensure proper support of the new system.

Installing the GReddy Supreme SP Exhaust

Now that the factory exhaust is out, you can assemble and install the GReddy system. Follow the order shown in the instruction manual, but the general procedure is consistent across most GT-R exhaust swaps.

Step 1: Test Fit the Components

Before applying any sealant or tightening bolts, loosely assemble the entire system on the ground to ensure all parts align correctly. The Silver Supreme SP system is designed to be a direct fit, but sometimes slight adjustments are needed. Verify that the flanges match up and that no component is twisted. Pay attention to the orientation of the muffler tips – they should be centered in the bumper cutouts.

Step 2: Install the Front Pipes

Begin at the front. Use the new gaskets supplied by GReddy (or OEM gaskets if you prefer). Place a gasket on each turbo outlet, then lift the front pipe into position. Hand-tighten the bolts to hold it in place, but do not fully torque them yet. Reinstall the O2 sensors into the bungs on the front pipes. Use anti-seize compound on the sensor threads to facilitate future removal.

Step 3: Attach the Mid-Pipes

With the front pipes loosely mounted, attach the mid-pipes using the supplied band clamps. Slide the clamps over the joint but leave them loose enough to allow movement. Install the hangers onto the rubber isolators – a small amount of silicone spray helps. Ensure the pipes are not contacting the chassis or drivetrain components. Check all clearances and adjust as needed.

Step 4: Hang the Rear Muffler Section

Lift the rear muffler into position and hook it onto the rear hangers. Connect it to the mid-pipes using the provided band clamp, again leaving it loose. Adjust the exhaust tips so they sit evenly within the bumper openings. Tighten the hanger bolts and then the band clamps to the manufacturer’s recommended torque (typically around 35–45 ft-lbs for band clamps). For the flange bolts, use a torque wrench and your vehicle’s factory specification, usually 30–40 ft-lbs for 12mm bolts and 45–55 ft-lbs for 14mm bolts.

Step 5: Tighten in Sequence

To prevent leaks and binding, tighten all fasteners in a logical sequence:

  1. Start at the front pipe to turbo flange, torque all four bolts evenly in a star pattern.
  2. Move to the mid-pipe connections, alternating sides.
  3. Finally, torque the muffler section into place.
  4. Go back and double-check every bolt and clamp after the first tightening pass.

Final Checks Before Lowering the Vehicle

Before you lower the car off the jack stands, perform these essential inspections to avoid problems later.

  • Visually inspect all connections. Ensure no bolts are loose and that gaskets are seated uniformly. Look for any metal-to-metal contact between the exhaust and the underbody that could cause rattles or heat damage.
  • Check ground clearance. The Supreme SP system is designed to maintain factory ground clearance, but verify that the lowest point of the exhaust is not lower than the chassis rail. If it is, adjust the hangers or slightly rotate the pipes if possible.
  • Reconnect the battery. Attach the negative terminal and ensure it is tight. If you disconnected any wiring for the O2 sensors, recheck those connections as well.
  • Clean any grease or lubricant off the exhaust with a degreaser. This prevents burning smells during the first startup.

Testing and Break-In Procedure

With the car back on the ground, it is time to fire up the engine and evaluate the installation.

Step 1: Cold Start and Idle Check

Start the engine and let it idle. Listen carefully for any hissing sounds that could indicate an exhaust leak at the flanges. If you suspect a leak, use a piece of cardboard or a rag to carefully feel for puffing air around each joint (do not touch hot components). Slight smoke or steam from the exhaust tips during the first heat cycle is normal as oils and coatings burn off.

Step 2: Warmup and Re-torque

Allow the engine to reach operating temperature. After the first heat cycle, re-torque all fasteners while the system is still warm, as the metal expands and can loosen the original torque. Pay special attention to the band clamps and exhaust flange bolts.

Step 3: Test Drive and Listen

Take the vehicle for a short test drive (10–15 minutes). Drive at varying speeds and loads to evaluate the sound and performance. Listen for any rattles against the chassis, especially under acceleration or over bumps. If you hear a drone in the 2000–3000 rpm range, check that the Helmholtz resonators are not contacting anything. After the drive, park on a level surface and re-check for leaks while the system is hot.

Step 4: Break-In Period

Like many aftermarket exhausts, the Supreme SP may become slightly louder and develop a deeper tone after a few hundred miles as the insulation inside the muffler settles. This is normal. After approximately 500 miles, perform a final torque check on all accessible fasteners.

Common Mistakes and How to Avoid Them

  • Not using new gaskets. Reusing old gaskets almost guarantees leaks. Always use the ones supplied with the kit or purchase OEM replacements.
  • Over-tightening band clamps. This can distort the tubing and damage the clamp. Follow the manufacturer’s torque spec.
  • Failing to check O2 sensor placement. Ensure the sensors are threaded fully and that their wiring does not touch the exhaust or suspension components.
  • Rushing the clearance check. A rattle at idle or under load is frustrating and often requires reworking part of the installation. Spend the extra few minutes verifying clearance.

Additional Resources

For further guidance, refer to the official GReddy Performance website for product specs and technical support. A well-made video installation guide can also provide visual reference for tricky steps. If you encounter specific fitment issues or want to learn more about GT-R exhaust theory, forums such as GT-R Life have dedicated threads with real-world tips from experienced owners.

Conclusion

The GReddy Supreme SP GT-R exhaust installation is a rewarding project that can dramatically improve both the sound and performance of your vehicle. By following this expanded step-by-step guide, you can confidently perform the installation yourself, saving labor costs and gaining a deeper understanding of your car’s exhaust system. Remember to prioritize safety, take your time with each connection, and consult a professional if you encounter any unexpected obstacles. With proper installation and a short break-in period, your GT-R will deliver the enhanced driving experience that only a high-quality aftermarket exhaust can provide.