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The RB20DET: A Legendary Engine That Deserves a Proper Exhaust

The Nissan RB20DET, a 2.0-liter turbocharged inline-six that powered the iconic R32 Skyline GTS-t and dozens of other sports models, remains a favorite among JDM enthusiasts and drift builders. Its iron block, strong bottom end, and responsive turbocharging make it a capable platform for everything from street cruising to competitive motorsport. However, the factory exhaust system was designed for cost and noise compliance, not maximum performance. Restrictive catalytic converters, narrow piping, and resonant chambers choke the engine's potential. Upgrading to a quality aftermarket exhaust system is one of the most effective modifications you can make. A well-matched exhaust improves spool, increases peak power, enhances throttle response, and transforms the driving experience with a more aggressive soundtrack. This guide covers the science of exhaust flow, the components that make up a complete system, and the top brands that deliver real gains for your RB20DET.

From R32 Skyline to Drift Legend

The RB20DET debuted in the late 1980s as Nissan's entry-level performance engine for the R32 chassis. It featured a single Garrett T3 (or T25) turbocharger, intercooler, and a DOHC 24-valve head. Despite its modest 2.0 liters, it produced around 210 to 215 horsepower stock, with a broad torque curve. In the drift world, the RB20DET became a favorite for its reliability, low cost, and ability to rev past 7,000 RPM. With an upgraded exhaust, many owners have seen gains of 30 to 50 horsepower at the wheels, along with faster spool and a more linear power delivery. Today, the RB20DET is still widely used in Silvias, Skylines, and engine-swapped builds, making exhaust knowledge essential for anyone building a budget-friendly JDM powerhouse.

Why Exhaust Flow Matters for Turbocharged Engines

Turbocharged engines rely on efficient gas flow both into and out of the turbocharger. The exhaust system serves two critical roles: removing spent combustion gases from the turbine housing and reducing backpressure in the exhaust manifold. When backpressure is high, the turbo must work harder to spin, increasing lag and limiting peak boost. A free-flowing exhaust system lowers the pressure differential across the turbine, allowing the turbo to spool faster and maintain higher boost levels at lower RPM. On the RB20DET, this translates to earlier torque onset, improved mid-range power, and a reduction in exhaust gas temperatures (EGTs). A well-designed exhaust also helps prevent detonation by evacuating hot gases quickly, which is crucial when increasing boost or running aggressive timing.

Exhaust System Basics – What You Need to Know

Understanding fundamental exhaust principles helps you make informed decisions when selecting parts. The following concepts apply directly to the RB20DET.

Backpressure and Scavenging: Separating Myths from Facts

Older wisdom claimed that engines "need" backpressure. That's a myth. Naturally aspirated engines benefit from careful tuning of exhaust pulse timing (scavenging), but turbocharged engines always perform better with minimal backpressure. The turbine itself acts as a restriction, and additional restrictions after the turbo (like small piping or restrictive mufflers) only hurt performance. The goal is to reduce post-turbo backpressure as much as possible, while still controlling sound to meet local regulations. For the RB20DET, a 3-inch (76mm) exhaust system is the standard for most street and track applications. Anything smaller will limit high-RPM power; anything larger may cause a slight torque loss on a stock turbo but works well with upgraded turbos.

Materials: Stainless Steel vs Titanium vs Mild Steel

The material affects weight, cost, durability, and sound. Stainless steel (usually 304 or 409 series) is the most popular choice for RB20DET exhausts. It offers excellent corrosion resistance, retains its appearance with minimal care, and has a crisp, clean tone. Titanium is lighter and more expensive, with a higher-pitched exhaust note that some enthusiasts love. It also develops a blue/purple heat discoloration that adds aesthetic appeal. Mild steel is the cheapest but rusts quickly if not coated or painted. It produces a deeper, warmer sound. For a street-driven RB20DET, stainless steel provides the best balance of performance and longevity. If you track the car and care about weight savings, titanium cat-backs are worth considering.

Exhaust Diameter: Selecting the Right Size for Your Power Goals

The exhaust pipe diameter must match the engine's airflow capacity. A stock RB20DET with small turbo (T25) can gain from a 2.5-inch or 2.75-inch exhaust, but 3-inch is still optimal because it minimizes backpressure without causing excessive noise or drone. Once you upgrade the turbo to a T3/T04E, GT28, or larger, a 3-inch system becomes essential. At power levels above 400 hp, consider 3.5-inch or even 4-inch exhausts, but these require careful muffler selection to avoid unbearable drone. The rule of thumb: for street use up to 350-400 hp, a 3-inch stainless steel turbo-back exhaust is the sweet spot for the RB20DET.

Key Exhaust System Components for the RB20DET

A complete exhaust upgrade involves more than just a muffler. Understanding each component helps you build a cohesive system.

Turbo Downpipe and Front Pipe

The downpipe connects the turbo outlet to the rest of the exhaust. The factory downpipe is often the most restrictive part due to its small diameter and kinked bends. An aftermarket downpipe with a smooth mandrel-bent transition from the turbine flange to the main exhaust pipe significantly reduces restriction. Many downpipes also include a flex section to prevent exhaust leaks from engine movement. Combined with a front pipe (the section between downpipe and catalytic converter), this is where the biggest flow improvement occurs. Upgrading the downpipe alone can yield 10-15 hp on a stock RB20DET.

High-Flow Catalytic Converters vs. Test Pipes

RB20DET cars in many countries require catalytic converters for road legality. A high-flow cat (200 or 300 cell) flows much better than the factory unit while still cleaning emissions. Test pipes (straight pipes) replace the cat entirely for maximum flow, but they make the exhaust louder, can cause a check engine light on some ECUs, and are illegal for street use in many regions. For a street-driven RB20DET, consider a high-flow cat from brands like MagnaFlow or MetalCat. If you compete in drift or track days, a test pipe is acceptable at the track and can be swapped out for road driving.

Cat-Back vs. Turbo-Back Systems

A cat-back system replaces everything from the catalytic converter back, including the intermediate pipe, muffler, and tailpipe. It improves sound and reduces weight but leaves the restrictive downpipe and cat in place. A turbo-back system replaces the entire exhaust from the turbo outlet, including downpipe, front pipe, catalytic converter (or test pipe), and cat-back. This yields the maximum performance gains because every restrictive factory component is removed. For the RB20DET, a turbo-back 3-inch system is the recommended path for anyone serious about performance. Many brands offer bolt-on kits that include all necessary gaskets and hardware.

Top Brands for RB20DET Exhaust Systems – In-Depth Review

Blitz – Aggressive Sound and Proven Track Performance

Blitz has been a staple in the Japanese performance scene since the 1990s. Their RB20DET exhaust systems, such as the Blitz Nur-Spec and Blitz Realize TT, feature straight-through muffler designs with minimal baffling, producing a raw, aggressive tone that is unmistakable. The Nur-Spec is a single-exit, 3-inch system made from polished stainless steel. It's lightweight and flows exceptionally well, making it a top choice for drift cars. The Realize TT offers a more subdued sound with twin-tip mufflers, suitable for daily driving. Both systems include mandrel bends and high-quality hangers. Blitz exhausts are known to fit R32 Skyline and compatible chassis with minimal adjustment.

HKS – Japanese Engineering Excellence

HKS produces some of the most refined exhausts for the RB20DET. Their HKS Hi-Power and HKS Silent Hi-Power lines are iconic. The Hi-Power features a large, straight-through muffler with a distinctive burnt titanium tip option. It delivers a deep, throaty sound that becomes aggressive under full throttle but remains civilized at cruise. The Hi-Power system uses high-quality 304 stainless steel and TIG welding. The Silent Hi-Power adds additional baffling to reduce noise for street legality without sacrificing flow. HKS also offers specific downpipes and front pipes that integrate perfectly with their cat-back systems. For a daily driver that sees the occasional track day, HKS provides the best balance between performance and livability.

Fujitsubo – Artisan Craftsmanship and Smooth Power

Fujitsubo is renowned for exquisite build quality and a focus on sound tuning. Their Fujitsubo Legalis R and Fujitsubo Super Ex are popular RB20DET options. The Legalis R uses a patented "R-Damper" muffler that reduces drone while maintaining a sporty note. The Super Ex is a more aggressive, lighter system with a wider pipe diameter. Both feature polished stainless steel and precise fitment. Fujitsubo claims their exhausts improve mid-range torque on the RB20DET, which is noticeable on the street. The systems are also very durable, withstanding years of use without rusting. Fujitsubo is a fantastic choice if you prioritize build quality and a refined exhaust note.

Apexi – Innovation with Adjustability

Apexi offers the unique Apexi N1 Exhaust and Apexi EXV adjustable systems. The N1 is a lightweight, single-exit design with mechanical (baffle) adjustability – you can change the sound level by swapping or removing a silencer insert. This is ideal for owners who need a quiet exhaust for street use but want full flow at the track. The EXV uses an electronic valve that opens at a preset RPM or boost level, allowing a stealthy idle and full aggression when the turbo spools. Apexi's systems are made from durable stainless steel and have excellent fitment. The adjustability gives Apexi an edge for those who want versatility without buying two exhausts.

Tanabe – Deep Tones and Lightweight Construction

Tanabe exhausts, especially the Tanabe Medallion series, are known for their deep, muscle-car-like growl. They use a unique canister muffler design that is both lightweight and effective at reducing noise. The Tanabe Touring Medallion is a popular RB20DET choice because it offers a pleasant sound without excessive drone. Tanabe also offers a Tanabe Pro Medallion for those who want a louder, more aggressive setup. The tubing is mandrel-bent stainless steel, and the systems are designed to be direct bolt-on for R32 and other RB20DET-equipped vehicles. Tanabe is a less expensive option compared to Blitz or HKS but still delivers excellent quality.

Other Notable Brands

Greddy (Trust) offers the Greddy Evolution GT and Greddy SP series for RB20DET. The Evolution GT is a dual-exit system with a unique muffler design that produces a clean, European-style note. Tomei is famous for their titanium exhausts – the Tomei Expreme Ti is incredibly light (saves up to 15 pounds over stainless) and has a distinct, high-pitched howl. Kakimoto makes the Kakimoto Racing Gigant, a single-exit system with a massive tip that's popular in drift circuits. All these brands have proven dyno results, and you can find them at Japanese parts retailers like Nengun Performance or RHDJapan. Be sure to check compatibility with your specific chassis and year model.

How to Choose the Right Exhaust for Your RB20DET Build

Matching Exhaust to Turbo Upgrades

If you are running the stock T25 or a small upgrade like the T28, a 3-inch turbo-back system is ideal. For larger turbos like the GT3071R or GT3582R, consider a 3.5-inch downpipe transitioning to 3-inch cat-back, or a full 3.5-inch system for power above 500 hp. The exhaust must match the flow capacity of the turbo's turbine outlet flange. Many aftermarket downpipes use a 3-inch outlet that bolts directly to a 3-inch cat-back. Always confirm flange patterns – common flanges are 4-bolt (Nissan standard) or V-band on some upgraded turbos.

Sound Preference: Track, Street, or Daily Driver

Exhaust sound is subjective, but it directly affects your experience and legal compliance. Large single-exit systems (Blitz Nur-Spec, Tomei Expreme) are loud and aggressive, suitable for track use or lax noise regions. Dual-exit systems (Apexi N1 dual, Fujitsubo Legalis R) often have a deeper, more refined sound. If you drive the car daily, consider a system with resonators or a high-flow muffler like the HKS Silent Hi-Power. Drone at highway speeds can be fatiguing, so look for systems that include a Helmholtz resonator or are designed to reduce resonant frequencies. Many forums have sound clips – listen before you buy.

Budget Considerations and Long-Term Value

Entry-level mild steel exhausts can cost as little as $200-400, but they will rust within a few years. Mid-range stainless steel cat-back systems from Tanabe or Apexi range from $400-600. Full turbo-back systems from premium brands like Blitz or HKS cost $800-1200. Titanium systems can exceed $1500. The best value for most RB20DET owners is a mid-tier stainless steel turbo-back system. It provides excellent flow, durability, and resale value. Avoid cheap, unbranded eBay exhausts – they often have poor fitment, thin tubing, and subpar welds that leak. Invest once and enjoy the performance for years.

Installation and Tuning Tips

Professional vs DIY Installation

Installing a cat-back exhaust is a moderate DIY job, requiring basic hand tools, jack stands, and penetrating oil for rusty bolts. The most challenging part is the downpipe and front pipe on R32 Skylines due to limited working space. Turbo-back installations often require removing the turbo heatshield and sometimes the catalytic converter heat shield. If you have a lift and air tools, allow 2-4 hours. For a first-timer, expect a full day. Pay attention to sealing – use new gaskets and properly torque flange bolts. Consider applying anti-seize to bolts that may need future removal. If you lack experience, a shop specializing in JDM cars can install it for around $200-400. When doing it yourself, be careful not to damage oxygen sensor wires.

ECU Tuning and Fuel Management After Exhaust Upgrade

A free-flowing exhaust will cause the engine to breathe more efficiently, which can lean out the air/fuel mixture if the ECU is not adjusted. On a stock RB20DET, the factory ECU can often compensate up to a point, but for best results and safety, you should install a piggyback (e.g., Apexi Power FC, Nistune) or a standalone ECU (e.g., Haltech, Link, or MaxxECU) and have it tuned on a dyno. Expect a 20-30 horsepower gain from a turbo-back exhaust and tune combined. The tune also enables you to maximize boost and ignition timing safely. If you're on a tight budget, at least install a wideband oxygen sensor to monitor AFR. Lean conditions can cause detonation and damage. Upgrading the fuel pump (to a Walbro 255 or equivalent) is also recommended for any RB20DET with increased boost.

Noise Regulations on Track and Street

Many racetracks enforce strict noise limits (usually 90-105 dB at a certain distance). Straight-through exhausts without resonators can easily exceed these limits. If you plan to track your RB20DET, check the sound output of your chosen system. Some exhausts, like the HKS Silent Hi-Power or Fujitsubo Legalis R, are designed to stay under common track limits. For street driving, excessive noise can attract police attention and fail vehicle inspections. In Japan, the JASMA certification indicates the exhaust meets certain noise standards. Look for this mark when buying Japanese brand exhausts.

Emissions Compliance with High-Flow Cats

If your region mandates emissions testing, you need a catalytic converter. Even with a high-flow cat, a properly tuned RB20DET can pass most smog checks when the engine is healthy. Some aftermarket cats use a metallic substrate that heats up quickly to reduce cold-start emissions. Be aware that using a test pipe will likely cause an emissions failure and may trip a check engine light due to the rear oxygen sensor reading no catalyst activity. If you alternate between test pipe and cat, consider using an oxygen sensor spacer to keep the light off. Ultimately, choose a system that complies with your local laws to avoid fines.

Frequently Asked Questions About RB20DET Exhaust Systems

Will a larger exhaust cause lag?

No, a free-flowing exhaust reduces backpressure and actually helps the turbo spool sooner on the RB20DET. Some tiny turbochargers can experience a slight loss of torque with extremely large pipes (4-inch), but on the RB20DET, a 3-inch exhaust is optimal and will not cause lag.

Do I need to upgrade my intercooler with an exhaust?

Not immediately, but if you increase boost, an upgraded intercooler is a wise next step. The exhaust alone will not significantly increase intake temperatures. However, as you push for more power with a tune, the factory intercooler becomes a bottleneck. A front-mount intercooler (FMIC) is a common upgrade that complements the exhaust.

How much horsepower can I expect?

On a stock RB20DET, a turbo-back exhaust + tune typically yields 30-50 wheel horsepower gains. With other bolt-ons (FMIC, intake, boost controller), many owners reach 280-300 whp reliably. The beauty of the RB20DET is that it responds well to modifications, but the exhaust is the foundation.

Final Thoughts – Unlock Your RB20DET’s Potential

The RB20DET is an engine that rewards careful modification. An exhaust system is not just a sound upgrade – it's a performance necessity. Brands like Blitz, HKS, Fujitsubo, Apexi, and Tanabe have decades of experience building high-flow systems that improve response, power, and reliability. When you pair the right exhaust with a proper tune, the RB20DET transforms from a decent factory engine into a thrilling, responsive powerhouse. Whether you are building a street car, a drift machine, or a time-attack weapon, investing in a quality exhaust is the first step toward realizing the full potential of your RB20DET. For further reading, check out detailed dyno comparisons on SAU Community or technical articles on MotoIQ that explain exhaust theory in depth.