Boost Your Genesis Coupe: The Ultimate Turbo Guide

Deciding to boost your Hyundai Genesis Coupe is an exhilarating step, opening up a world of performance previously only dreamed of. For many enthusiasts, the journey begins with choosing the right forced induction system. While the allure of raw power is undeniable, navigating the options, understanding the underlying principles, and ensuring reliability can be a daunting task. This guide aims to demystify the process, providing a comprehensive look at turbocharging your Genesis Coupe, with a particular focus on a well-regarded kit designed for daily driving and longevity.

Understanding Boost: Why PSI Isn't Everything

One of the most common misconceptions circulating about turbocharged cars is that a higher PSI (Pounds per Square Inch) always equates to more power. This isn't necessarily true, and understanding why is crucial to making informed decisions about your build. PSI is merely a measurement of pressure exerted on a certain volume of air. Consider the difference between pressurising a drinking straw and a large, 12-inch diameter pipe. Both can be pressurised to, say, 6 PSI, but the pipe holds immensely more air. Cars are, at their core, glorified air pumps; the greater the volume of air you can pack into the engine, the better the performance will be.

Let's look at some real-world examples:

• Hyundai Genesis Coupe 2.0T: ~14 PSI stock for 274 HP
• Subaru WRX STI: ~17.5 PSI stock for 310 HP
• Hyundai Genesis Coupe 3.8 Turbo (with a specific kit): 6 PSI for ~525 HP

Why does the 3.8 Turbo produce significantly more power with less boost? The answer lies in the volume of air. A smaller turbo might pressurise a smaller volume of air to a high PSI, but that volume may be insufficient for the engine's peak efficiency. Conversely, a larger turbo can move a much greater volume of air, even at lower PSI, leading to substantially more power. Simply knowing the PSI without considering other variables such as cylinder volume, piston compression ratio, or the turbo compressor map provides very little useful information.

Turbocharger vs. Supercharger: The Clear Winner

When considering forced induction for your Genesis Coupe, the debate often boils down to turbochargers versus superchargers. While superchargers might appear simpler to install, their inherent design leads to significant disadvantages compared to a well-engineered turbo kit, especially for the Genesis Coupe 3.8L engine.

Efficiency and Performance

Superchargers are inherently less efficient than turbochargers. This reduced efficiency means:

• A supercharger will yield less performance for the same PSI compared to a turbo.
• The 3.8 engine is prone to heatsoak. Because a supercharger is less efficient, it needs to run at higher PSI to achieve similar performance to a turbo. This increased boost generates more heat, placing a higher thermal burden on the engine.
• Running higher boost to match or exceed a turbo's output subjects the engine to more stress, potentially reducing the reliability of components like pistons, rings, and rods.

Cost and Reliability

Beyond performance, superchargers also present drawbacks in terms of cost and long-term reliability:

• For a comparable setup of essential parts, a supercharger kit can be nearly £2000 more expensive than a turbo kit, even before accounting for gauges and tuning.
• A supercharger is a parasitic drain on the engine. It's driven by the crank and belt, which also power other accessories. The much tighter belt tension required with a supercharger can prematurely wear the aluminium main journal bearings.
• Alterations to the rotating assembly, such as a lightweight crank pulley, have been linked to stress fractures on the crank. A supercharger similarly alters the wear and load on the crank, potentially accelerating wear and impacting reliability.
• Many supercharger kits for the Genesis Coupe have appeared and disappeared, while turbo kits have a proven and consistent track record. This historical context suggests greater long-term support and knowledge within the community for turbo setups.

Furthermore, some supercharger kits require sacrificing the windshield wiper reservoir and passenger fog light, which isn't the case with certain well-designed turbo kits.

In summary, turbocharging the Genesis Coupe 3.8 offers a more efficient, economical, and safer route to boosting your vehicle's performance.

The Remnant Performance Turbo Kit: A Closer Look

For Genesis Coupe owners, the Remnant Performance (RP) turbo kit has emerged as a highly regarded option, specifically designed for reliable daily operation on a stock engine block. Its "safety first" philosophy is evident in the inclusion of crucial components like an external oil cooler, a 6 PSI wastegate, and a custom billet oil sandwich plate, many of which were pioneering features in the market.

Reliability and Longevity

The RP kit's test vehicle has accumulated over 40,000 miles and three years of service with the turbo, demonstrating its capability for long life on a stock block. However, it's vital to remember that converting to forced induction significantly amplifies the consequences of poor maintenance or engine abuse. Neglecting oil changes, flooring a cold engine, or rapid throttle changes can lead to severe engine damage. Adhering to smart, safe driving and maintenance practices is paramount.

All-Inclusive Cost

The total cost for a Remnant Performance turbo kit, including essential accessories like gauges and a custom tune, typically ranges from £4790 to £5615, depending on your Genesis Coupe's specific model year (BK1 vs BK2) and your chosen turbo. This includes:

• Kit Cost: £3395 - £4290 + tax
• PnP Gauge Kit: £545 + tax
• AlphaSpeed Custom Big Turbo Tune: £850

Additional costs to factor in may include various tools, fluids, and potential modifications like a replacement A/C line for 2014+ BK2 models.

Choosing Your Turbo: GTX3582R Gen 2 vs. 70 OMEGΛ

As of April 2021, Remnant Performance offers two custom-designed turbo options tailored for the Hyundai Lambda II 3.8L engine:

While both options provide excellent performance and fast spool for the 3.8L Genesis Coupe, the 70 OMEGΛ holds a distinct advantage. Its advanced features, including dual ceramic ball bearings and a lightweight billet compressor wheel, allow it to spool significantly sooner and build boost faster. This translates to an impressive ~30 HP more performance compared to the GTX3582R, making it a highly cost-effective upgrade for the performance gained.

The 70 OMEGΛ also benefits from state-of-the-art turbo housing and compressor wheel design methodologies, including hyper-precise point-milling and exhaustive optimisation of airflow. These advanced geometry and aerodynamics techniques enable this mid-frame turbo to support up to ~1200HP on a wide range of engine sizes, making it perfectly suited for the 3.8L Genesis Coupe. Its design techniques are so effective they form the basis of modern, high-performance turbos, far surpassing older designs in terms of spool time, flow rate, and overall performance.

Many owners report that the 70 OMEGΛ spools so rapidly that turbo lag is negligible, providing a driving experience akin to a supercharger but with all the benefits of turbo efficiency. This upgrade can transform your Genesis Coupe into a machine with a power-to-weight ratio comparable to high-end sports cars like the Dodge Challenger Hellcat or an Audi R8 V10.

Anticipated Power Output

With a 70 OMEGΛ turbo and a stock motor running the recommended 6 PSI tune, current estimates suggest approximately 525 crank horsepower. Wheel horsepower (WHP) figures typically range between 415-450, depending on drivetrain losses. This represents a significant increase, with about 20-22 horsepower per PSI on top of the stock engine performance. These figures place your Genesis Coupe's power-to-weight ratio in a league with some seriously impressive and expensive machinery.

Understanding the 6 PSI Boost Configuration

The Remnant Performance turbo kit is designed to operate at 6 PSI of boost by default, controlled by a semi-custom wastegate. This wastegate automatically opens at 6 pounds of boost to regulate turbo speed and pressure. While the kit ships with a 6 PSI spring, you are also provided with 3.0 PSI and 4.5 PSI springs, which can be combined or used with a boost controller to achieve higher pressures (up to 2.5 times spring pressure).

The choice of 6 PSI is rooted in safety and reliability. The OEM pistons and their surrounding rings and ringlands are designed to accommodate thermal expansion and contraction within a specific temperature range on a stock engine. A turbocharger significantly raises both pressure and temperature, narrowing the spacing between these rings. Excessive pressure and heat can cause the rings to overpower the ringlands, leading to piston damage or even engine failure.

Years of testing have shown that the OEM rings and pistons in the Genesis Coupe 3.8L can reliably tolerate boost in the 6-8 PSI range with turbos of the RP kit's size. While some owners may cautiously push towards 10 PSI, the default 6 PSI configuration prioritises engine safety and long-term durability on a stock block. For those seeking more power, professional engine building assistance is highly recommended.

Is an Engine Build Necessary?

A common concern among enthusiasts is whether boosting the Genesis Coupe 3.8L necessitates a complete engine build. In short, with the right kit and tuning, the answer is absolutely not for the Remnant Performance setup.

Historical misconceptions often stem from the early days of 3.8T conversions. At that time, understanding of the Genesis Coupe's ECU was primitive, leading to dangerous tunes with incorrect air/fuel ratios, disabled safety limiters, and other fatal flaws. These failures were mistakenly attributed to the engine's inability to handle boost, rather than the fundamentally flawed tuning practices.

Today, knowledge of the Hyundai Lambda II engine and its ECU has vastly improved. Advanced tuning networks, notably AlphaSpeed (which played a pivotal role with Remnant Performance), offer levels of control and safety previously unimaginable. These modern tunes ensure appropriate air/fuel ratios and maintain crucial safety parameters, allowing the stock motor to reliably handle the boost provided by the RP kit.

When you invest in a Remnant Performance kit, you're also gaining access to a knowledgeable network of passionate individuals who are dedicated to the Genesis Coupe platform. This community provides invaluable support, answering questions and contributing to ongoing research and development, ensuring you're never left in the dark.

Installation and System Overview

Installing a turbo kit is a significant undertaking, typically requiring 20-60 hours depending on your mechanical skill. While step-by-step video series are often available, preparedness and a willingness to improvise are key.

Piping Overview: Cold Side and Hot Side

A turbo system has two main sides:

• The Cold Side: Air enters through a conical filter near the passenger side headlight, is drawn into the turbo's compressor (cold side), then routed downwards to the intercooler at the front of the car. Once chilled, the air travels back upwards on the driver's side, crosses over to the passenger side engine bay, and connects to the throttle body and intake manifold.
• The Hot Side: Exhaust gases, instead of simply exiting through the catback, are collected from the engine and fed into the turbo's turbine (hot side) to spin it. This spinning generates boost on the cold side. After passing through the turbine, the exhaust gases exit the vehicle as normal.

Do You Need a Boost Controller or Aftermarket ECU?

For the Remnant Performance kit, a boost controller is not required, as the included wastegate manages the 6 PSI boost level. However, for those planning to build their motor and push beyond the kit's scope, manual boost controllers like Grimmspeed are an option.

Similarly, an aftermarket ECU is not necessary. The AlphaSpeed tuning, developed in conjunction with the RP kit, provides excellent control. For highly modified, built motors, options like Haltech Platinum Pro/Elite 2500 (BK1) or MoTeC M142 / AlphaX (BK2) are available, offering advanced features like flex fueling and multiple maps.

Gauges: An Absolute Must

Running any forced induction setup absolutely necessitates gauges. The Plug & Play Turbo Gauge Kit, specifically designed for the Genesis Coupe with the Remnant Performance kit, is highly recommended. It provides crucial information such as Boost PSI, air/fuel ratio (AFR), oil temperature, and oil pressure, allowing you to monitor your engine's health and performance in real-time. These gauges often feature customisable backlighting and warning thresholds for critical parameters.

Essential Fluids and Components

Proper fluid maintenance and component selection are vital for the longevity of your turbocharged engine.

Oil Recommendations

It is strongly recommended to use AMSOIL SAE 5W-40 FS Synthetic European Motor Oil. This slightly thicker oil offers superior resistance to thinning at higher temperatures and against fuel contamination, providing enhanced protection for your engine under increased thermal load. For immediate needs, Quaker State Full Synthetic 5W30 is a viable alternative. Always remember that for built blocks, your engine builder's oil recommendations should take precedence due to different internal tolerances.

Spark Plugs

Your kit will include 6x NGK 93819 (1-step colder) spark plugs. It is crucial to manually gap these to 0.028" using a gap feeler gauge, regardless of factory claims, to ensure optimal performance and prevent issues.

Crucial Engine Protection Habits for 3.8T Drivers

To ensure the long and healthy life of your turbocharged Genesis Coupe, adopt these five critical habits:

1. Idle Before Shutdown: After driving, let your car idle for 30-60 seconds before turning it off. This prevents "oil coking" (burnt oil) and ensures your turbo and oil remain healthy.
2. Disable TCS: Immediately after starting the car, disable the Traction Control System (TCS) by pressing the button to the left and below your steering wheel. Driving with TCS enabled can lead to a lean condition and catastrophic engine damage.
3. Oil Every 3K: Change your engine oil every 3 months or 3000 miles. This frequent oil change schedule is your new religion for a turbocharged engine.
4. Warm Your Motor: Never go to full throttle and boost until your oil temperature reaches at least 150°F (ideally 190°F operating temperature).
5. Get a MAP-Enabled Tune: Ensure your tune is MAP Sensor-enabled. This significantly enhances reliability and safety for your turbocharged vehicle.

Installation Tips and Tools

While a basic set of metric socket wrenches and screwdrivers can get the job done, several additional tools and consumables will make your installation significantly smoother:

• O2 sensor socket (shallow and long)
• Permatex copper anti-seize
• Vibra-Tite Blue Gel threadlocker (easier than Loctite)
• Extra PTFE thread sealing tape
• Pentosin CHF 202 for power steering refill
• 7 quarts of cheap 5W40 oil for the 300-mile break-in period
• Plastic paint scrapers for cleaning the oil pan
• Assorted t-bolt and worm gear clamps
• Tesa 51036 tape and quality 3M electrical tape
• Assorted zip ties
• Permatex assembly lubricant (red)
• Adjustable AN fitting wrenches
• DEI Reflect-A-Gold thermal tape
• Asian blue formulation coolant
• Brakleen cans
• Shop rags and paper towels
• Extendable 3/8" drive socket wrench with flexible head
• Aerokroil thread penetrating fluid
• ATF (if automatic transmission)
• Large prybar for shifting the motor
• Brake caliper hangers
• Exhaust wrap
• A reliable impact driver (e.g., Milwaukee)

Common Installation Hurdles and Solutions

• Improvisation is Key: You'll encounter OEM components (brackets, hoses, tabs) that need to be moved, bent, trimmed, or cut to make space for the new piping. Take a deep breath and assess how to free up the necessary room.
• Engine Movement: Some Genesis Coupes have a shifted front subframe. A large prybar can help shift the motor enough to clear hot side piping.
• 2014+ A/C Line: If you have a 2014+ BK2, the A/C line will likely interfere with cold side piping. You'll need to purchase and install a UAC HA112532C A/C line and have your A/C recharged.
• Checking Torque: Regularly confirm that blowoff valve and wastegate hex bolts are snug. Use Loctite 243/Vibra-Tite Blue or Loctite 567 on all NPT fittings. AN fittings do not require tape or sealant. V-band clamps need specific tightening procedures with a rubber mallet.
• New Noises: Expect some new rattles or noises. Well-placed exhaust wrap, secured with zip ties or metal zip ties for hot areas, can often resolve these.

Remember, the Remnant Performance community is a valuable resource; many have faced similar challenges and can offer assistance.

The Robustness of the Genesis Coupe Engine

The 3.8-litre Lambda engine in the Hyundai Genesis Coupe is widely regarded as a robust powerplant. Experts like Bisi Ezerioha of Bisimoto Engineering have praised its potential for development, even for the rigorous demands of competitive motorsport. This inherent strength, combined with a well-designed turbo kit and diligent maintenance, makes the Genesis Coupe an excellent platform for forced induction.

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