Why the HKS Legamax Premium Is a Worthy Upgrade for Your Integra Type S

The HKS Legamax Premium exhaust is engineered specifically for the Integra Type S, offering a deeper, more aggressive exhaust note without the drone that plagues many aftermarket systems. Constructed from high-quality stainless steel and featuring HKS’s signature straight-through muffler design, this system delivers a noticeable improvement in both sound and performance. The Legamax Premium is known for its refined tone at cruising speeds and a more pronounced roar under hard acceleration, making it a popular choice among enthusiasts who want an enhanced driving experience without excessive cabin noise.

Beyond sound, this exhaust system can provide modest gains in horsepower and torque, particularly when paired with other intake and tuning modifications. The precise fitment and factory-style hangers ensure a straightforward installation, but attention to detail during the process is critical for avoiding leaks, rattles, or misalignment. This guide expands on the basic installation steps with deeper technical insight, torque specifications, and practical tips to help you complete the job like a professional shop.

Tools and Materials You Will Need

Before lifting the car, gather everything you need. Having the correct tools on hand will prevent frustrating mid-job trips to the hardware store and ensure you can tighten every fastener to the correct specification.

Tools Required

  • 3/8-inch and 1/2-inch drive socket wrench set with metric sockets (10mm, 12mm, 14mm, 17mm)
  • Torque wrench capable of 20–80 ft-lbs (1/2-inch drive recommended for manifold bolts)
  • Flathead screwdriver or pry bar (for releasing exhaust hangers)
  • Floor jack and two heavy-duty jack stands (minimum 3-ton capacity)
  • Penetrating oil (PB Blaster or similar)
  • Rubber mallet (for gentle persuasion on stubborn hangers)
  • Safety glasses and mechanic’s gloves
  • Exhaust gasket (check if the HKS kit includes one; if not, purchase a new OEM gasket for the manifold-to-cat connection)
  • Anti-seize compound (for exhaust bolts, optional but recommended)
  • Shop rags or paper towels

Parts Supplied in the HKS Kit

  • HKS Legamax Premium muffler assembly
  • Mid-pipe and connecting pipes (if applicable to your vehicle configuration)
  • Hardware pack: bolts, nuts, washers, and springs (check against the included instruction sheet)
  • Hanger bushings (if replacements are included)

If your HKS kit does not include a replacement gasket for the manifold flange, order an OEM gasket from your local dealership or a trusted parts retailer. Reusing the old gasket can lead to exhaust leaks and a hissing sound that will require rework.

Preparation and Safety

Park the Integra Type S on a level, solid surface. Allow the exhaust system to cool completely if the engine has been running — a hot exhaust can cause severe burns. Chock the front wheels to prevent any movement while the rear is elevated. Disconnect the negative battery terminal if you plan to work near any sensors or wiring, though this step is optional for a simple exhaust swap.

Apply penetrating oil to each of the exhaust flange bolts and hanger brackets. Give the oil at least ten minutes to work into the threads. This will dramatically reduce the risk of snapping a bolt, especially on vehicles exposed to road salt or moisture. Have a bolt extractor set on standby in case a stubborn fastener does break — it happens, and being prepared saves hours of frustration.

Step 1: Raise and Secure the Vehicle

Position the floor jack under the rear differential or the designated rear jacking point on the Integra Type S. Lift the rear of the vehicle until you have at least 18–24 inches of clearance beneath the chassis. Place jack stands under the reinforced frame rails near the rear subframe — never place them under the exhaust or suspension components. Gently lower the car onto the stands and verify that it is stable by giving it a firm shake at the bumper.

Step 2: Remove the Stock Exhaust System

Loosen the Flange Bolts

Start at the exhaust manifold flange where the downpipe connects to the rest of the system. Using a 14mm socket, loosen the two bolts that hold the front pipe to the manifold. These bolts are often tight due to heat cycling, so a breaker bar or long-handled ratchet helps. If they resist, apply additional penetrating oil and wait a few minutes before trying again. Do not remove them completely yet — just break them loose.

Release the Hangers

Slide under the vehicle and locate the rubber exhaust hangers. There will be three or four hangers supporting the mid-pipe and muffler sections. Using a flathead screwdriver or a pry bar, gently work each rubber hanger off its metal post. A spray of silicone lubricant on the rubber makes this step significantly easier. If a hanger is particularly stubborn, use the rubber mallet to tap the hanger arm and dislodge it.

Lower the Stock System

With all hangers released and the flange bolts loosened, remove the flange bolts completely. Carefully lower the stock exhaust system — it is heavier than it looks, so have a second person help if possible. Slide the stock exhaust out from under the car and set it aside. Inspect the old gasket at the manifold flange; if it is crushed or damaged, discard it and plan to use a new one during installation.

Tip: If you plan to sell the stock exhaust or reuse it later, wrap it in a moving blanket or bubble wrap to prevent scratches during storage.

Step 3: Install the HKS Legamax Premium Exhaust

Test Fit Before Final Tightening

Remove the HKS Legamax system from its packaging and lay the components out underneath the car in their approximate positions. This dry fit helps you understand how the pipes will route and where the hangers need to align. It also allows you to identify any fitment issues before applying torque.

Install the Mid-Pipe and Front Connections

Begin at the manifold flange. Place a new gasket over the studs or onto the manifold face, then lift the HKS front pipe into position. Hand-thread the bolts (and any included springs) to hold the pipe in place. Do not fully tighten yet — leave all fasteners snug but loose enough to allow adjustment.

Work your way toward the rear, connecting the mid-pipe sections as needed. The HKS Legamax system uses slip-fit connections with clamps on some variants; if your kit includes clamps, ensure they are oriented so that the bolt heads are accessible for tightening after alignment.

Attach the Muffler Section

Lift the HKS muffler into position and attach it to the mid-pipe. Again, keep all bolts and clamps hand-tight. Slide the exhaust hangers onto the metal posts — fresh rubber bushings may require a bit of force. A dab of dish soap or silicone spray on the bushings helps them slide without tearing.

Step 4: Align and Tighten Everything

Check Clearance and Tip Position

With the entire system loosely connected, step back and examine the exhaust tips through the rear bumper cutout. The tips should be centered left-to-right and sit at the same height. If they are off, grasp the muffler and gently shift it until the alignment looks correct. Also check clearance around the undercarriage — there should be at least 1/2 inch of space between the exhaust pipes and any chassis components, heat shields, or the rear suspension. Vibrations from contact will cause annoying rattles and potential damage.

Tighten to Specification

Once you are satisfied with the alignment, begin tightening all fasteners from front to rear using a torque wrench. Consult the HKS instruction sheet for exact values, but the following are common ranges for this type of exhaust system:

  • Manifold flange bolts: 30–35 ft-lbs (apply a small amount of anti-seize to the threads)
  • Mid-pipe clamps: 25–30 ft-lbs
  • Muffler hanger brackets: 15–20 ft-lbs

Over-tightening can strip threads or crush gaskets, leading to leaks. Use the torque wrench for every critical fastener. Recheck each bolt after the first heat cycle — thermal expansion can cause fasteners to loosen slightly.

Step 5: Check for Exhaust Leaks and Noise

Start the engine and let it idle. Listen carefully for any ticking, hissing, or popping sounds that indicate a leak at the flange connections or clamp joints. Have a helper rev the engine gently while you inspect each joint with a gloved hand (feel for air pulses) or use a length of hose held to your ear — this will amplify any leak sounds.

If you detect a leak, shut off the engine, allow the exhaust to cool, and tighten the suspect connection slightly. If the leak persists, remove the bolt and inspect the gasket — it may be misaligned or damaged. Do not proceed to driving until all leaks are resolved, as an exhaust leak can cause poor performance, fuel smell, and even carbon monoxide intrusion into the cabin.

Step 6: Lower the Vehicle and Perform a Final Inspection

Remove the jack stands and lower the car to the ground. With the vehicle at ride height, re-check the exhaust tip alignment — the suspension settles slightly when weight is on the wheels, which can shift tip position by a fraction of an inch. Make minor adjustments by loosening the rear hangers and repositioning the muffler as needed.

Inspect all hangers one more time to confirm they are fully seated and that the rubber is not twisted. Twisted hangers can fail prematurely and will cause the exhaust to sag. Finally, tighten the negative battery terminal if you disconnected it.

Post-Installation: The Settling Period

Drive the car gently for the first 50–100 miles. During this period, the exhaust system will settle into its final position as the rubber hangers stretch slightly and the metal expands and contracts through heat cycles. After this break-in period, re-torque all flange bolts and clamps. This step is often overlooked but is crucial for long-term noise-free operation.

The HKS Legamax Premium exhaust also develops its characteristic sound over the first few hundred miles. Fresh packing material in the muffler needs time to condition, so do not judge the final tone immediately after installation. Give it at least 500 miles for the sound to mature.

Comparison: HKS Legamax Premium vs. Stock Exhaust

Weight savings: The HKS exhaust system weighs approximately 8–10 pounds less than the stock system on the Integra Type S. This reduction in unsprung weight contributes to slightly improved suspension response and a small reduction in overall vehicle mass.

Sound profile: At idle, the Legamax Premium is marginally deeper than stock but remains civilized. Under moderate acceleration, it produces a clean, sporty note without excessive boom. At wide-open throttle, the tone becomes aggressive and purposeful, particularly above 5,000 RPM. On the highway, cabin noise is only slightly elevated — HKS engineers focused on minimizing drone at cruising speeds.

Performance: While not a dramatic increase, dyno tests on similar platforms have shown gains of 5–8 horsepower and 6–9 ft-lbs of torque when paired with a cold-air intake and a tune. As a standalone modification, expect more of a sound improvement than a power leap.

Maintenance and Long-Term Care

The stainless steel construction of the HKS Legamax Premium resists corrosion, but the exhaust tips and visible weld areas can tarnish over time. Clean the tips with a metal polish specifically designed for stainless steel every few months to maintain their luster. Avoid abrasive pads that can scratch the finish.

Check the hanger bushings annually for cracks or excessive softening. Heat and road grime degrade rubber over time; if a hanger feels loose or the exhaust shifts position, replace the bushing before it fails. HKS sells replacement hanger kits, or you can use universal polyurethane bushings for added durability.

If you live in a region with harsh winters and road salt, consider applying a rust inhibitor to the underside of the exhaust system — even stainless steel can develop surface corrosion in extreme conditions. A product like WD-40 Specialist Corrosion Inhibitor or Boeshield T-9 works well.

External Resources

Final Thoughts

Installing the HKS Legamax Premium Exhaust on your Integra Type S is a rewarding project that combines mechanical skill with a tangible improvement in driving enjoyment. The system’s high-quality construction and thoughtful design make it one of the most refined aftermarket exhausts available for this platform. By following the detailed steps above — paying close attention to alignment, torque specifications, and post-installation settling — you will achieve a professional-grade result that delivers reliable performance and a sound that turns heads without annoying your neighbors.

Take your time during the installation, use the correct tools, and do not skip the re-torque step after the first heat cycle. Your Integra Type S will thank you with a crisp exhaust note and a subtle but satisfying bump in performance every time you press the throttle.