Why Upgrade Your RSX Type S Exhaust?

The RSX Type S, with its high-revving K20Z1 engine and close-ratio six-speed transmission, is already a capable performer from the factory. However, the stock exhaust system is a compromise engineered for noise compliance, cost, and durability rather than peak performance. Upgrading to a high-quality cat-back system addresses several key areas that directly affect driving experience and output.

  • Horsepower and Torque Gains – A less restrictive exhaust reduces back pressure, allowing the engine to expel exhaust gases more efficiently. This translates to a measurable increase in wheel horsepower and torque, particularly in the mid-to-high RPM range where the K20Z1 thrives.
  • Weight Reduction – Factory exhausts are typically made from heavy mild steel with multiple resonators and bulky mufflers. A cat-back system from MagnaFlow uses lighter stainless steel and simpler muffler designs, shedding up to 15–20 pounds from the rear of the car, which improves handling and acceleration.
  • Improved Sound Quality – The stock exhaust is muted and subdued, especially above 5,000 RPM. A performance exhaust provides a deeper, more aggressive tone that enhances the driving experience without being obtrusive at cruising speeds.
  • Better Heat Management – Aftermarket exhaust systems with mandrel-bent tubing and larger diameter pipes allow hot gases to exit faster, reducing under-hood and under-chassis temperatures. This can prolong the life of nearby components and reduce intake air temperatures when combined with a cold air intake.
  • Aesthetic Appeal – Many cat-back systems feature polished stainless steel tips that improve the rear appearance of the RSX Type S, giving it a more purposeful, track-ready look.

Introducing the MagnaFlow Cat-back Exhaust System

MagnaFlow is a well-respected name in the exhaust industry, known for investing in research and development to produce systems that balance performance, sound, and durability. For the RSX Type S, MagnaFlow offers a complete cat-back system (part number 16436 for the dual-tip configuration) that replaces everything from the catalytic converter back.

Key Features of the MagnaFlow Cat-back System

  • High-Quality Stainless Steel Construction – Both 409 and optional 304 stainless steel are used, ensuring resistance to corrosion and long-term durability. The piping and muffler shells are TIG-welded for a clean, leak-free finish.
  • Mandrel-Bent Tubing – Unlike crush-bent pipes found on some cheap systems, MagnaFlow uses mandrel bending to maintain a consistent 2.5-inch diameter through every bend. This preserves exhaust velocity and prevents restriction.
  • Straight-Through Muffler Design – The internal muffler core uses a perforated tube surrounded by acoustic fiber packing, allowing exhaust gases to pass directly through while canceling harsh frequencies. This reduces back pressure significantly compared to a chambered muffler.
  • Deep, Aggressive Exhaust Note – MagnaFlow engineers tuned the muffler and resonator package to produce a sporty tone that is unmistakable but still tolerable for daily driving. The sound is deeper than a typical “fart can” and has a refined growl under throttle.
  • Direct Fit with No Modifications Required – The system uses factory-style flanges and hanger locations, so installation is straightforward. It includes all necessary hardware and gaskets.

Installation Process

Installing the MagnaFlow cat-back on an RSX Type S is a job that can be completed in an afternoon with basic hand tools, a jack, and jack stands. The overall difficulty is moderate, even for a first-timer, provided you allow for possible rusted bolts on older cars.

Tools Required

  • Socket set with metric sockets (10 mm, 12 mm, 14 mm, and 17 mm)
  • Combination wrenches
  • Jack and two jack stands
  • Penetrating oil (e.g., WD-40 or PB Blaster)
  • Razor blade or scraper (to remove old gasket material)
  • Torque wrench (for final tightening)

Step-by-Step Installation

  1. Preparation – Park the car on level ground. Loosen the lug nuts on the rear wheels, then jack up the rear of the vehicle and secure it on jack stands. Remove the rear wheels to create more access to the exhaust hangers.
  2. Removing the Stock Exhaust – Locate the bolts connecting the cat-back pipe to the catalytic converter (two bolts with springs). Apply penetrating oil to these bolts and the rubber hangers. Use a 14 mm socket to remove the bolts. Then unbolt the two brackets that attach the exhaust to the chassis. Pull the stock exhaust out from under the car; it may require some wiggling past the rear suspension.
  3. Clean and Prepare Flanges – Scrape off any old gasket material from the catalytic converter outlet flange. Install the new gasket provided with the MagnaFlow kit.
  4. Install the New System – Begin at the front: attach the intermediate pipe (or front section) to the catalytic converter flange. Use the supplied hardware and tighten to 35 ft-lb. Work your way rearward, loosely connecting each section. MagnaFlow systems often come in two or three pieces that slide together with clamps.
  5. Attach Hangers – Push the rubber hangers onto the metal pegs of the new exhaust. Ensure the exhaust is centered in the rear bumper cutout before tightening any clamps fully.
  6. Final Torque and Check – Once everything is aligned, tighten all clamps and flange bolts according to the instructions. Re-install the rear wheels, lower the car, and start the engine. Check for leaks at every joint; a soapy water spray can help identify small leaks.

Tip: If the stock bolts are heavily rusted, replace them with stainless steel hardware to make future removals easier. Also, consider using anti-seize compound on the hanger pegs and bolts.

Power Gains from the Upgrade

The primary motivation for many RSX Type S owners is the promise of real, dyno-verified horsepower gains. While a cat-back alone won’t transform the K20Z1 into a 300-hp monster, it is one of the most cost-effective bolt-ons for freeing up upper-rpm power.

Expected Power Gains

Dyno tests on bone-stock RSX Type S models show that the MagnaFlow cat-back system can deliver:

  • 12–14 wheel horsepower at peak (typically around 6,500–7,500 RPM)
  • 8–10 lb-ft of torque in the mid-range (4,000–6,000 RPM)
  • Smoothed-out torque curve with less drop-off after 7,000 RPM

These figures can vary by 1–2 hp depending on the specific dyno, air temperature, and whether the car has any other modifications (like a cold air intake). The gains are primarily in the high-RPM region because the stock exhaust is most restrictive there; a cat-back effectively allows the engine to “breathe out” better at high revs.

Real-World Driving Impact

On the road, the power gains translate to stronger acceleration from 4,500 RPM to redline. Passing maneuvers and top-end pulls feel more urgent. The improved throttle response is noticeable, as the engine spools up more quickly without the droning restriction of the factory muffler. Some drivers also report a slight improvement in fuel economy during highway cruising, though this is marginal (1–2 mpg at best).

Dyno Chart Analysis

Independently published dyno graphs from RSX forums (such as ClubRSX) show a typical before-and-after comparison: stock power around 190–195 whp (depending on the car) and after the MagnaFlow cat-back, readings of 202–207 whp. The gains are consistent across multiple runs, with no loss of low-rpm torque. The air-fuel ratio remains safe, though it often leans out slightly in the upper revs, which is why many owners add a Hondata FlashPro tune to fully optimize the setup.

Sound Quality and Performance

Sound is subjective, but the MagnaFlow cat-back system is widely regarded as one of the best-sounding options for the RSX Type S. It strikes a balance between an aggressive track car tone and daily-driver livability.

Characteristics of the MagnaFlow Sound

  • Idle – A deep, mellow rumble that hints at the added volume without being obtrusive. The idle is noticeably deeper than stock.
  • Cruising (2,000–3,000 RPM) – The cabin experience is surprisingly quiet, with minimal drone. MagnaFlow’s internal fiber packing and resonator design keep harmonic resonance to a minimum, making highway drives comfortable.
  • Acceleration (4,000–6,000 RPM) – The sound becomes louder and more aggressive, with a metallic rasp that drives enthusiasts to keep the engine singing. It is not ear-splitting but definitely announces the car’s performance intent.
  • Wide-Open Throttle (7,000+ RPM) – At redline, the exhaust note is raw and pure, a classic inline-four scream that makes every gear pull a thrill. It is louder than stock where it counts.

Decibel Comparison

Testing by aftermarket installers shows that the MagnaFlow cat-back measures approximately 92 dB at 3,000 RPM under load, versus 88 dB for the stock exhaust. At 5,000 RPM, the MagnaFlow reaches 98 dB while the stock system registers 93 dB. This is a noticeable but not obnoxious increase, and it passes noise testing at most track days.

Comparison to Other Brands

When compared to other popular cat-backs like the Apex’i N1, Invidia Q300, or Skunk2 MegaPower, the MagnaFlow offers a deeper, less raspy tone. The N1 is louder with more drone, the Q300 is quieter and more refined, and the MegaPower is very loud and aggressive. MagnaFlow sits in the middle—ideal for someone who wants performance and a sporty sound without waking the neighbors or causing fatigue on long trips.

Additional Considerations

ECU Tuning and Combo Upgrades

While a cat-back alone does not require a tune, pairing it with a cold air intake and a performance header (especially a 4-2-1 design) will increase the need for engine management. The ECU’s fuel trims can compensate within a limited range, but for maximum power gains and to prevent a lean condition, a FlashPro or K-Pro tune is highly recommended. Tuned RSX Type S with full intake, header, and cat-back can reach 220–230 whp safely.

Emissions and Legality

The MagnaFlow cat-back system retains the factory catalytic converter, so it will pass visual inspections and tailpipe emissions tests in most states. However, removing the catalytic converter (by installing a test pipe or racing header) would violate EPA regulations and fail inspection in areas with strict smog laws. The cat-back itself is fully street-legal everywhere.

Cost and Value

At approximately $450–$550, the MagnaFlow cat-back is competitively priced compared to boutique exhausts. Considering the stainless steel construction and proven power gains, it offers excellent value. The system typically lasts the life of the car if not damaged by road salt, as the 409 stainless steel is resistant to corrosion but can develop surface rust over time (which does not affect performance).

Conclusion

The MagnaFlow cat-back exhaust system is a well-engineered upgrade for the RSX Type S that delivers measurable horsepower gains, an improved sound, and a lighter, more durable construction. Installation is straightforward for any moderately experienced DIYer, and the results are immediately felt and heard. For owners who want to take the first step toward serious performance or simply want a more enjoyable daily driving experience, the MagnaFlow cat-back is a top-tier choice that will not disappoint.

Whether you are chasing tenths at the track or just want to put a smile on your face during every commute, this exhaust system helps unlock the full potential of the legendary K20Z1 engine.

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